 The first of the two which I was talking was digital to analog converters also called D slash A converter or simply as in your terms everything you want to shorten that essentially I have a digitized I have a digital word generally it can be coded in number of ways one the most standard coding is binary codes or BCD codes sometimes what else code I do gray code or some excess codes excess 3 excess some specific applications but generally most case the digital data is binary. Okay, so any analog voltage which is equal to equivalent of that digital data is shown here let us say I have a digital number a binary number n bit number. So what is the way we write in the case of digital numbers the 1010 essentially give the coefficient of 2 to the power and whatever we are writing. So first is 2 to the power 0 to the power 1 2 to the power 2 2 to the power 3 and a 0 a 1 a 2 are essentially 1 0s if this term occurs then a 1 is 1 if this does not occur a 0 0 okay that is what the number essentially we are talking if you have a n bit number from 2 to the power 0 to 2 to the power n minus 1 this is how I will represent digital number is that correct standard way of converting n l decimal to binaries or other any code then I say with this digital number I will multiply by some constant V okay as I repeat this can be 1 this can be 0 this can be whatever the actual digital number you have accordingly 1 0 1 0 will appear okay. So I write I take 2 n minus 1 out so I write V 0 is now a n minus 1 half n minus 2 half 1 upon 2 to the power n minus 2 a 1 2 n minus 1 a 0 into so now I see so if these are the numbers and these are the coefficient now with age I if I can make a circuit which does this job then I am converting given data into analog voltage this is constant V is my fix I am fixing it so this is constant so given a digital number it is coefficient in this form 1 0 whatever I write and write in this form and I get I get equivalent if I add all these terms I will get equivalent analog voltage that is what we are trying to so depends on a a 0 a 1 a 2 this V will be varying V 0 will be varying if this is 1 this is 1 this is 1 all all 1 let us say so 1 plus half plus 1 by 4 plus 1 by 8 plus 1 keep doing till n and then this is 2 to the power say 8 7 that is into V so you just write add all of it and you get the volt analog voltage you change some numbers are zeros so there will be different V 0 is that clear if I age are not once then there will be some other V 0 will appear so proportionally whatever is your digital number I can create equivalent analog voltage so we are converting a digital data into analog data if it is not so trivial but we will see how will you do it this is the principle I am using typically what DAC does therefore if you see a block diagram you have a DAC which has a voltage which we call reference voltage V refer it receives a digital word which is n bit wide so I have in a data like d 0 d 1 d 2 d 3 d n minus 1 the first one down is least significant bit the uppermost is most significant bit what that does uses the digital data input does some tricks with this V reference this is that proportionately constant I was talking to this V reference is something which we are decide how much voltage I want and then I will get an output what we say the V output is somewhere related to fraction of the reference voltage and this fraction of course is a function of digital data okay is that correct fraction is a function of digital data 1 0 1 0 whatever total you get f will be different V reference is my reference voltage so f times V reference will be V out as I already said these the word which is n bit wide so how many combinations it can give at the input possible 2 to the power n let us say I have a 4 bit number so how many input combinations possible 16 combinations 0 0 0 0 0 0 0 0 1 1 keep doing 1 1 1 4 1 so 16 combinations so larger the bit width of the word larger input combinations will come is that clear to you now my problem start something like this so for example a 4 bit DAC needs 4 bit resolution and what does that mean the word which I am now saying first time is the word resolution now what is the resolution I am saying since I have 16 input combinations okay for each input combination there will be some V 0 let us say V o 1 V o 2 V o 3 and I must be able to separate this V o 1 from V o 2 from V o 3 V o 4 sufficiently accurately so that each input combination has a discrete value of V 0 which is different from other V o's is that resolution word clear to you I want to resolve all 16 input combinations at the output independently which can be separated as if and they will be separated equally because each bit changes only by 1 so for each this it will shift by equal amounts so I want to see what is essentially in mechanical what do we say least count so what is the smallest this I can do which will separate the 2 words or 2 bits okay 2 different input words please remember this word as a 8 combination let us say or 4 combinations 2 to 4 bit word that means D 0 D 1 D 2 D 3 so there will be possible 16 combinations for you and these 16 each should give me V 0 which is distinctly separate from the last is that clear this word is called resolution if I make 8 bit DAC so what will be its resolution related to 2 to the power how many combinations I can get 2 to the power 8 which is 256 input combinations so one can see now the same this number if I reduce into 256 separation will be smaller is that correct separation will be smaller the smallest accuracy which I can create so I say what is the advantage of earlier last time I showed you some graph you recollect that graph I was trying to discretize something last time I showed what is the game I say as close I discretize I will actually replicate digital to analog or vice versa as close the digital data is as close will be my similar thing will be the analog equivalent so is that word clear why resolution should be higher because it will give you more accurate conversions so one of the major feature of any A to D or D to A converter is its resolution how much it results is that clear smallest number is related to what LSB least significant bit so for that least significant bit what is the next possible number which I can resolve next bit is what I am looking that is called the resolutions so I am interested in so if I have why not make say 24 bit DAC or 32 bit DAC what will have what will happen the hardware which will require to create larger resolution will be larger in actual value itself. So typical ADCs what size can be for resolutions 8 bits most DAC or ADCs are 8 bit resolution if you want more accuracies you have 10 bit 12 bit of course you pay something if you increase bits which this I am not going to tell you there are many many problems in increasing the resolutions there are many errors some of them are called differential errors some are integrated errors some are aperture errors some are quadrature errors so there are to gain errors there are missing bits so there are large problems in conversions is also another ADC which we use very often is called Sigma Delta modulators is very important modulation in whole of the analog circuit area it is a actually a one bit modulator or converter but we can do 8 bit collection 16 bit 32 bit many things we can do which is what we will see later that why Sigma Delta's but right now assume whatever simple things I am talking just for the heck of information I gave you okay so this fact is understood by you that I am looking for better resolution if I want to have accuracies of my choice so fair enough so I define a term F which is fraction which is given by D which is the word digital word divided by 2 to the power n I give you definition so that you understand if D is a 4 bit word 4 bit wide what is the 4 bit number smallest 4 bit number smallest 4 bit number which has the one at the MSP so 1 0 0 otherwise what will be next 1 0 0 1 1 0 1 1 1 1 0 1 and 1 1 these are 4 possible numbers smallest among them is 1 0 0 0 so what is this 1 0 0 essentially in decimal 8 8 so we define the weight of D is whatever is the smallest this number 8 divided by 2 to the power 4 because n bit you said n is 4 so 2 to the power 4 8 by 16 is called the fraction which we are looking for how much is the fraction here half is that so we out will be how much we reference by half we reference by 2 okay take another case if you have a 3 bit wide DAC what is the smallest 3 bit numbers I can create 1 0 0 so it is 4 2 to the power 3 is 8 4 by 8 F is again half is that clear let us say if we reference is 5 volt then V0 will be half into 5 by this 2.5 it is a fraction of a reference is the word the bit size word bit width you are talking if you have a 4 bit word the smallest 4 bit is 1 0 0 0 and then next number is 1 0 0 1 no no no because the yeah you have a point then I will not use the first 2 are only I will use only 2 bit numbers so 4 bit width has a resolution which is at the MSB what is the minimum number I can create because I am going for the 0 to MSB so I want to look at MSB what is what number I am going to resolve okay the smallest MSB I am looking is 1 0 0 0 so if we have a resolution of 2.5 volt each of them so every bit will now go to next will be 2.5 volt away from it so 5 volt next will be 7.5 fraction of that now there is something that is the reference I am creating which can be any value I put 5 volt it can put 1 volt yeah that is the maximum up to which I will go that is the fraction of that only I am looking how much I will go so for the just look at the figure then you will I will come back to it if you are saying here is more in things which will be clear to you this is my 3 bit wide number okay what are the numbers 0 0 0 0 0 0 0 1 up to 1 1 1 is that correct these are the 8 possible combination of 3 bit wide numbers so I say okay I plot here V out by V reference okay I plot here V out by V reference the ratio okay then I say what I am really looking is at 0 I want 0 0 0 0 for 0 0 0 output voltage should be 0 because all bits are 0 so output is 0 the next time when I come with 0 0 1 okay then I say it should be 1 by 8th of fraction should be 1 8th for 1 1 1 what should be the fraction therefore this is 1 2 8th 3 8th at 1 1 1 which is the highest 3 bit number how much it will be 7 by 8 so at 7 by 8 and beyond this it will not be 4 3 bit number is that correct so the maximum number which I can create using a 3 bit deep DAC is 7 8th of V out by V reference or 7 8th of V reference is the maximum voltage I can create and how much is the resolution I am creating 1 8th of V reference correct 1 8th is the resolution that is what I said you so if you are 3 bit number 1 by 2 to the power 3 is the resolution f is the fraction resolution is 1 8 smallest number which I can separate on the output is 1 8th of reference so what is the full scale reflect this for the 3 bit code full scale is the how much was full scale here 7 by 8 generally what should I write 2 to the power n minus 1 divided by 2 to the power n put n is equal to 3 8 minus 1 is 7 2 to the power 3 is 8 so 7 by 8 is that clear so in general for any n bit code the maximum BFS which I can get the full scale as it is called is 2 to the power n minus 1 upon 2 to the power n times V reference in our case for 3 bit it is 2 to the power 3 minus 1 by 2 to power 3 which is 7 8 that is the now this something which I am assuming what is this curve looks like straight line is that correct the problems which I said in real life this achieving the proportionality is a cause of error there so we may not get the kind of steps we are getting and there is an issue how much we can tolerate okay so what is the smallest reference this V reference is that resolution is clear smallest resolution is 1 LSB which is V reference divided by 2 to the power n in our case if it was 8 1 8th of V reference is the smallest voltage I can separate is that correct if I want better one than what should I do I want this to be better than 5 what should I do I go from 3 bit wide DAC to 4 bit wide DAC then I will get V reference by 16 is that clear if I make 12 bits I will get 1 upon 2 to the power 12 into V reference so smaller the resolution I am asking for larger is the bit size of the DAC I will have to use and larger the size of bits will say hardware you will start proportionately increasing is that point clear is that okay so this is an issue which DAC people have to attain to that is you can see what we said at 1 0 0 it is the see I want to have 3 values at which I am looking whether I am in straight line 0 0 0 full scale and the midpoint so I looked into half I looked into 7 by 8 I looked into 0 and I joined this curve I say I believe that linearity is maintaining myself that means equal spacing of 1 8th is possible is that clear okay now how do I implement this a output voltage proportionate k input Nikola just minus R2 by R1 or 1 plus R2 by R1 times VIN can be transferred to V0 but VIN what should be the case digital word here is the first circuit which is the easiest circuit called binary weighted DAC okay before okay before this just see the switch a switch which I am going to show in my this is the second switch don't this we are already used in sample hold this is another switch which I am going to use in by the next DACs representation what is the first thing I am putting here an inverter a CMOS inverter receive an input C bar which is my control okay so how much is here C it is a follower so that is C but can you think if C bar is 0 what is the output here 1 so what will be output here 1 is that followed if it is 1 what will be output here 0 so what will be output here 0 so its input is that clear is that clear if I give 0 here I get 1 if I give 1 here I get 0 if it is 1 I have 1 here if it is 0 so why in this in between I did because I want to buffer it up okay this is my inverter and I am creating 1 0 from an inverter depending on the input I give I can create input to this this is input of opium I should write okay this is the line which I am showing the input to the opium now I will show you but we are anyway looking for 1 and 0 so let it saturate so only thing is that 0 is not minus VSH but it is single ended power supply so the lower end is only 0 no why should you 50 5 volt is sufficient for almost every circuit in opium most opiants are 5 volt supply the experiment which you give me 741 which we give you is essentially we are using it 15 to show you good working of opium all opiants 8576 ILM 321323 any numbers you talk they are mostly 5 volts and these days even lower than that 2.5 volts there is a circuit which is a 2.1 volt we are looking for 1.8 volt supply now okay so there are power supply I told you what is day before I started all this power supply which allow sub power ke upar hai to one to ka but abhi to have a 5 volt man we have analog circuit me abhi sub 5 volt ka supply leke chal nahi yeh kaya rahe hain ki yeh digital ke saad nahi jod nahi maha baad me jod nahi to dekli me we will see kya switch in the sense either it transfers 1 or it transfers 0 switch 1 and 0 what else which does no no no whenever it is 0 it is transferring 0 whenever it is I am switching actually whenever it is 0 I am transferring 1 whenever it is 1 I am transferring 0 it is controlled because depend on the control I will create 1 or 0 no no just do not do that this is the different circuit this is what I am I am going to use some circuit and I thought what is that block inside is this here is what let us see what I am here is that switch okay this all square blocks are switches the switch receives 2 inputs one is minus vr the other is ground 1 and 0 and it is controlled by bit which you are bit n minus 1 that is msp to lsp is that clear how many of them will be as many bits deck you want those many will be this is msp this is lsp or each such switch first switch has a resistance or second has 2r third will be 4r 2 to the power and finally n n 1 will be or 0th bit will be 2 to the power n minus 1r please remember the highest msp will get only r and lsp we get 2 to the power n minus 1r these are the resistances they are connected here this is that line is that man okay this line this line is this line each r is connected at this line each switch is connected at this which is the input to the p bar is this individual control 1 and 0 are the bits and a number voltages I am entering through this switch that is the vdd or ground only thing is I am putting vr as minus why did I put minus can you think why minus so the way I am doing it if this is this bit is zero the upper one passes is that okay if this bit is zero what is the switch performance input is zero output becomes one so this one is transferred this is like a equivalently what is it looking like so what is doing it if this bit is zero it transfers one if this or maybe vice versa sorry I mean I can do otherwise I can put a opposite of that okay if it is zero let us say it transfers zero if it is one it transfers one okay sorry I made a mistake because that is why I did some others I will do for all such bits you have there are a number of such switches now depending on the zero or one on this which is your bit data okay either voltage or either this volt or zero will appear at this so is that okay the since which allows either this or ground to pass at this depending on the bit availability zero or one I can pass voltage or zero volt okay if it is zero it does not add anything if it is one it that is a voltage it adds to that number is that correct so this into r dash upon r is that correct this into say minus vr r dash upon r into minus vr if this is one I get a v zero because of this as r dash upon r times v that is 10 volts b reference is that clear to you if this bit is one I will also get only thing is now why why it is r dash upon 2r you see my first figure which I showed you is that clear half half create karnathana r dash upon 2r yeah one fourth create karnai to r dash upon 4r n karnai the 2 to the power n minus r dash upon that so is that this equation now clear what is that equation this is a summer is that correct so may actually summer heat are karniya or yeh jo value he may be may be minus 10 is that clear to you yeh jo hai yeh minus 10 meh adjust kar diya aur is that correct yeh term nahi hai sanjo to yeh half nahi hai to yeh mere circuit meh bhi yeh so it does not add to the output so I now represent a output voltage which is corresponding to let us say give some numbers say let us say one zero and one and let us say all others are zero so yeh to minus 10 aya yeh zero aya aur yeh minus 10 aya so sum kitna hoga r dash upon r into minus 10 minus sign plus ho jaige to r dash upon r into 10 plus r dash upon r 1 upon how much let us say it is a 8 bit number so how much 2 to the power 4 minus that is 8 so r dash upon 1 upon 8r iska contribution meh is that clear but that can be opposite also it is a only a normand nature I can always put what you are saying is valid I am not denying I should not have shown that because that was switched somewhere else I just copied all that I need is this irrespective whether I call it C bar what I am going to get is zero will transfer to one is that correct all that I should do therefore I should put another one to create C C bar so that I will transfer exactly zero zero here one one here because that is what my switch is asking ah drive kone karega us a drive kone karega one zero ke levels kone dega signal source aap ke paas jo hai wo kuch bhi ho sakta hai kyuki bits to kahin aur circuits yaha so usko dry kone karega yeh driver se us yeh buffer hai yeh driver send you cannot connect direct aisa toh fir siv register se pura world banjata na ek khel hai aapko ek power electronics padaya ho ka kabhi there is a circuit called dc to dc converters so there is something which we do when we put in between them Prasoch ho okay you have point but there is not a correct point in circuits you must drive current provide kone karega piche wale circuit ko umin mat karo which I don't know which circuit is going to come from the piche se jo bits aare hai wo kish circuits aare hai mujhe nahi pata mujhe drive kar nahi patega is that clear to you buffer does not really give currents buffer buffer actually gives impedance match iska impedance or iska impedance match kar da ye are kuch bhi ho sakta aap I am least interested in other part of the circuit because this r is now is not going to load anything now because yeh r1 ke ho sakta hai 10 ke ho sakta hai 50 ke bhi ho I don't want this to connect with the my inputs okay so this is buffering only the impedance high impedance to low impedance states okay this is driving the input itself okay this is digital okay so yeh isko yeh to standard i2v converter bultein isko ek opam meh ne i2v converter hi hota hai nahi yaan se aane wala karan yaan jaar hai okay is that summer clear to you ek yeh hai ek yeh hai yeh sum ho raha hai aare ka jo bits zero hai uska zero sum ho ka jo one hai uska one ho ja uska proportionately wo term aha mil jai yaar aur function kya bataya meh ne what I am implementing is this is that clear so a DAC essentially can be created by putting some switches as I showed plus supplies plus a current to voltage converter or opam and actually it converts d to a at the output is that clear abhi aapko kya wala tha hai sum jo hai 8 bits hai to kitne yeh switches aur yeh lagenge 8 eksteen hoa to you can see because so many input kam nahin hai to 16 blocks lag jain jeetne jada ridhall karne ke baat karenge utna cost bhatata chara accuracy to bhedegi but cost bhi utna hi is that okay so how much accuracy you want you decide and then put money for that okay ek aur circuit hai iska then we will stop on this isko boltein dosara paehla to binary weighted DAC this is R2R DAC yeh bhi vada majedan hai ushi circuit ko thoda modify kiya hai deko isko bolte R2R usme switch hata diya meh ne thode indirectly isme ek normal switchi diya isko bolte SP DT kya boltein kya full form ho ka bola nahi single pole double throw so ek hi isme 2 connection deta hai hoa pole means yeh jo switch mechanical hai yeh pole boltein no not the our pole zero normal switch jo dikhata hai na aapko wo single pole single throw hi hai hoa ek connection deta hai bus ab ek issa 2 connect on off bhi kare aur 2 ko connect drive kare usko bolte single pole double throw it's much easier circuit than the one which you have a normal switches yeh aan dot laga hai wo hi connection hai yeh aan dot nahi hai woa connection nahi hai yeh you need not want to draw all nine of them you will draw at least three one two and n okay you first forget this R2R only look for this right side simple opam dikhaya gaya aapko current to voltage converter hai okay if P plus is grounded virtual ground but no current can sink here is that correct no current can sink here there is no if there is no connection on this line so it is floating if this has no input no connection to this line output remains zero no current I out because remember I out cannot flow if this is at virtual ground there is no sink path so one this is I am looking for a case when in which this floats that means output is zero the second time I want this to really go to through R2V reference some value of me essentially me kya bolu nahi aapko firs li kaya gaya gaya gaya gaya gaya gaya gaya two cases I am looking for one is this is my ground and floating nothing here okay so I out is zero no input output is zero and therefore V0 is also zero second case positive that no negative a virtual ground but virtual ground does not sink anything this is floating so current cannot flow there so if current can't flow output is zero okay now second case V minus ek resistance se ek V par raya oh yeah yeah you are you are right if there is no current the output voltage is I times R but if there is no current here the current is output is zero so output will go to zero initial condition if there is nothing there oh you are saying if there is a last capacitor there it will pre-charge yes it retains last charge but initially it will always be at zero it doesn't float it remains at floating at zero output remains at zero okay no nothing is going there if there is a V and this is R whatever I am going to get if this is the circuit then what is the output current going from here will pass through there and V0 will be essentially I out minus I out times this R R dash or calling isn't it so if I and I out will be proportional to total path it is going to see total I I will be decided by this and this values is that correct from a source V by R plus so much will be I out V minus this is R equal to R V minus this is equal to that so we find out how much is I out so if I out is a function of this is that correct I out is a function of this if this value changes V out will change if I out which is a function of this R if that R changes or this voltage changes then I out will change and therefore V0 will change is that correct if this combination allows me a different values a different equivalent of a digital bit then different outputs will be available is that correct similarly now what I can do I can do number of such resistances with number of V1 V2 sum here also again so I can have different VR VR combination as I did in the last case I can sum all such coefficients with different V and different R to get V0 sum of everything is that correct so that is the output voltage which is sum of each bit is that correct now how do I create this I repeat the two cases I am interested in in which negative is floating the other is it is connected through R to some reference value so what I do is there are the D is the date each each the bit if the bit is 0 okay I want please remember bit is 0 how much V0 I should get 0 is that correct 0 so depending on the bit I have either I will connect here or I will connect here is that correct if it is a 0 bit I will connect here if it is a 1 bit I will connect here is that clear this is what SPDT does we will not go into detail how I do it this switch but this is what switching we do so if I put R2R network R2R R2R R2R R2R and additional 2R to the ground I can say when they are floating this voltage will be re-referenced by 2 ratio of the 2 then it is further each will give re-reference by 2 of half of that half of that half of that half of that 2 to the power each will be half every time R by 2R V plus is always ground V plus is always ground so when this goes to connection here actually I am giving 0 potential to every one of them this is floating so obviously nothing is getting transferred from the data side is that correct so if corresponding to a data's either I will connect here or I will connect here if I connect here what does that mean I am transferring reference voltage part of the reference voltage at the output if I am connecting to the ground I am not transferring anything that is 0 so if it is 0 I connected to the ground if it is 1 I connected to the V minus point is that correct so depending on the value whether it is 0 1 0 0 either it will go to V reference by 2 plus V reference by whatever bits are once each will come on V minus through R to R combinations is that correct and correspondingly I out is n minus k k is the bits number I am talking k is equal to 0 to n minus 1 which bit number 0 1 to the dk V reference upon 2 to the power n minus k into 1 upon 2R okay a 2R this is the output current if d 0 okay 0 which term will go that is if this is 0 then I out is 0 corresponding plus next term is 1 this is 1 and this is n minus 1 whatever that value by 1 upon 2R will be transferred at the output keep transferring plus plus 0 plus 0 plus 1 whatever constant you have and you will get output voltage which is sum of all 1 bits at their position why this number is coming what is this actually going to give me that whole expression you keep remembering all that I am doing I am still doing this n minus 1 half n minus 1 1 upon 2 n minus 2 why same summer have you I am using is that correct same summer I am using by this circuit and this is essentially it is much easier to implement because only two kinds of registers are required no switches directly of that kind this single pole double throw is slightly interesting switch some other day I will show you how SPDT works okay is that clear so which this is what is this DAC is called it is called R2R R2R so it is called R2R DAC okay very famous it is got a the output voltage has something through with R I can adjust the value of V0 by adjusting V reference and the R value I choose is that correct so resolution can be adjusted by choice of R as well as V reference together so for a smaller number of resolution bits I can still get voltages separated by small numbers is that correct by adjusting R values is that clear to you this is slightly modification over binary weighted DACs that is why they are used last but not few two figures and we end it two minutes we will only show two of them and not discuss read in the this is not given in sedra smith not given in the books which I refer to you as analog books why because they are mixed signals so they are not but you can read any digital book any digital book they will have like a sterling ka kitab hai ya koi phi digital hardware ka kitab vijayi where ADC DACs are there so why is it being read in this course because it is not read in that course there they say opium is not our we do not mind how much digital is shown in our course we do not mind but they always mind and why are analogs not there so that is why we cannot show you details and you can come to our mixed signal course you can see 16 50 type a to d gd actually mixed signal ka major component a dc a DAC are four kinds of popular a chad duos lab mein ikor is ka version b hai bhi hai single slope ekor bhi hai multi step ekor bhi hai pipeline these are the easiest to show and this one is used maximum flash the what is the word flash mean instantaneously you know flash over the flash ram ram mein kya hota hai what the white is called fly flash there but i don't need but i rama ko flash ram mein kya hai what is the advantage over e proms or e square proms why it's flat flash is so important in e prom you have to put ultra wallet light for long time 30 minutes to erase the data okay it's also all erase e square prom you erase bitwise each bit is erased one by one electrically flash allows electrically erase like a e prom in one go all of it okay that's why it's called flash all gone and it is electrical so you don't need any light etc to be actually use light cup problem catch it has to be taken out put it below you this and first erase and then use it back in e square in flash you don't do electrically you erase everyone that's the only problem is e proms are much longer life than flash but abhi itna flash technology aksha hai okay so here this dekh liya abhi mein iska ek quickly 2 ADCs dikhatao aksha chala sabse pehle yei dekhatao ek poli pharatni pehle counting please draw this circuit very interesting simple circuit nothing great happening here okay i have clocks pulses which is my input to AND gate and the other input to AND gate is coming from a comparator okay the output of AND gate is given to binary counter as an input binary counter mein kya aksh type ka counter use karna chatao mein itne type ka up ko bata what is the triple counter means output of the first flip flop the second flip flop okay there is no common clock this not synchronous it is a asynchronous counter okay so yeh synchronous counter nahi asynchronous a clock ek paile ish mein clock input derain next time output of the first ffq is given to clock of the next stage okay what does that mean if you have 16 pulses the next will show you one in 8 pulses 8 wala next third flip flop four pulses ke baan aisa kyon bholtein usko kyon ki flip flop only triggers at either positive age or negative so negative age 8 ke baat 4 mein milega 4 ke baat 2 mein milega 2 ke baat so 8 pulses after 8 pulse you count only 1 that's why it is called counter 8 pulses counted as 1 through 4 flip flops okay 0 0 0 1 aaske aapko milga final 1 aate ke di aat count hoga otherwise o 0 0 0 chaltarate 1 0 0 0 0 1 0 0 finally ja 1 aate maa par shift okay then we say you are counted 8 pulses okay so here is a counter I repeat clock is one input pulses this this is a comparator which is receiving an analog input okay the other input of a comparator is coming from d2a converter abhi baat aan d2a converter which is essentially binary counter ka output jo hai wo a d2a converter ko diya gayain kyunki binary counter digital the digital ispe aur yahi se unka bits b bahar nika laga MSB to LSB kyunki a digitized data hi aar hai aur ye jo digital d2a converter e jo digital word yaha aar hai usko convert karke wo analog banar hai aur ye bd jo hai wo vs a compare karna ho is that correct aur usko output mein and get ko ye kya karna ho bata laga hai aapko idea 0 hai to yaha kya ho gaha 0 ja 1 hai to nee clock clock aiga to abhi aisa karenge ki jitna chahiye aitab tab to ye 1 raha hai aur jab ban karna hai to ye 0 aaj hai is that correct when it becomes 0 after time I decide then the clocks will not go okay and wo hi pulse jo ye 0 create kar rahe hai wo ye se clear ko bhi de sakte hai to flip clock can be reset to 0 0 0 okay otherwise it remains small so it always it does not participate remember we said does not participate when one when it is 0 it is called reset bar in karna and get a under to ulta karne 3 wo clear karne okay abhi daco kya kya if I start first pulse come the counter ka first flip flop jo hai wo 1 aega baki 0 0 rahenge okay to ye 1 LSB 1 hai 0 0 1st flip flop ka LSB last MSB hai anyway does not matter very much but for the sake of it to ye jo aapko mila pahela bit 0 0 0 1 samjo aaya 4 bit hai samjo to iska d2a convert kya main uske proportionate leh voltage create kya is that clear aur usse main a analog ko compare kya jo kya aapka data analog data since it is only one bit VD is always smaller than VA to VA if it is this this remains one and if it is remains one the next clock is allowed okay as long as this is one next pulse then what is the new bits will appear 0 0 1 1 samjo 4 bit ka hain 0 0 1 0 aega fir is ka d2a convert kya fir is ko VD nikala fir compare kya please remember ye the second bit one hota hai to power 2 to the power 1 ke power par 1 hora hai to jay se d2a converter main voltage extra ho jaila is that correct now start looking here number of pulses at 0 the analog output see output at this step which is coming through VD is 0 till the second pulse come this remains one jyotha hoi rahega second pulse aega to fir d2a convert fir se karega do uske le number ke le to jump karega second point pe chalaga till third pulse aane tak wohi rahega asha woh upar upar staircase se jaata rahega as long as you keep increasing pulses so ye VD jo hai ye baddha jaara staircase se is that clear why it is staircase bit was when the clock is there is still the next clock age the voltage is retained ye constant reta hai second clock aane ke baadi woh fir step karega 7 step par woh kareeb kareeb VA ke pass hai jaa jab ye 8th clock anner aaya ye isko cross kar let us say that is how the VA was as soon as it clock what does that mean VD is now higher than VA comparator output 0 and output 0 reset binary counter stops at the last value whatever before it sets bits shows you whatever the last bits here which allows VD to be higher than this when the next clock starts before that you start clear and recount the next VA you can give another VA and you can start counting is that correct 8 aane kithne bits 8 bits aane kithne 2 to the power 3 so 3 bit kahi ADC dekhaya jaara this is a 3 bit ADC 2 to the power 3 is 8 8 pulses will create 8 possible combinations therefore it is a 3 bit ADC is that what we learn every clock pulse D to A ka voltage badega aur woh compare karta rahega japta ghe 1 hain ne ne class aate rahin finally jab b VA ko cross karega whatever MSB to LSB data you are seeing is equivalent of that because uske aage to wo cross kar ghaan uske aage to wo reset karega isko 0 kar dega to no clocks so iss point ke upar jo bhi aapko MSB dikhega MSB to LSB aapka digital word hain equivalent of VA so chaar counter sain to iss main khatam ho jaata to 2 rha number 0011 main khatam ho jaata ya 0010101 main khatam ho jaata to each bit output will be proportional to the analog which you are giving is that correct chitna yeh jada ho gha utne bits kure bharin yeh 111 hote jain is that clear is that point clear chitne analog bada ho gha utne kap aapko aapko poshne ko lagega utna aapko bada na badega baki yaha kain ho gha to jaldi se it will show the bits this is called A to D converters and it is called counting why it is called counting yeh counter hain na pulse count karta rit hain aur usk main MSB LSB dikhaga rit hain as soon as it process VA it stops here is the digital number okay this is called counter accounting ADC last but not the least sapsay important ADC jo use hote hain jo ki one of the fastest available ADC is shown here ki jo TC word likha hain kya hote aapko kya boon bhai normaly codes kya vete digital ke binary binary coded gray excess codes ekor code hain temperature code kya hote hain thermometer code kya hote aapko yeh di yeh one number zero number hain core bit ka binary hain to char zero hain dcd na vete hote one hain digital two hain aap isko aadi thermometer code hain to iski theory yeh hain ki pahela to zero zero zero yeh kyuki usme zero yeh core bit thermometer code yeh hain next be same hain gray meh be kya karthe alternate chage karne na zero one one zero one one bhesa yaa aisa nahi aas thoda sa gray ka modify hain aap jitne jaisi man mein jitne yeh number hain utne ones thermometer code meh hote LSP ke nara this is yeh actual use hota isli aapko dikhaan and so on and so on. So saat meh kitne hain humge seven ones humge is that correct this is called TC yeh ADC jo flash use karthe mo TC kreate kar hain isli aapko batadaya ke TC skya hain thermometer codes essentially now you must remember we hain talked about decoders encoders everything usme hum boltein ki 2 to the power n yeh the 8 bit to 3 bit gaya to decoder hote 8 to 3 decoder but actually decoder ka aisa koi meaning nahi from lower bits to higher bits is called encoding from higher bits to lower bits is called decoding it need not be in the binary form that is 2 to the power 3 nahi 2 to the power 3 minus 1 b kar ka any code to any code yeh left side meh input rakhoh right side meh output rakhoh or koi b soft function se aap humesh aap left to right jaisat hain truth table is basically that so anything to anything from lower bits if you go to higher bits it is called encoding from higher bits you go to lower bits it is called decoding however in our digital course we keep saying 8 to 3 3 to 8 because we want to keep binary values but aisa koi definition hum nahi bana hain aur wo karik nahi bhi yeh baat samaj me hain bhi hain doko if higher bits to lower bits are shaped I say it se decoding if going from lower bit to higher bit I call it encoding okay code so meh aapko sir yaa itne comparators lagi hu hain this one of them is my analog input which is my analog each is a comparator and yaaapar r ka ek series string laga rakhah hain each tap ke upar isko voltage taps se ek example dettein each tap hain voltage 3 bit ke liya kitna yeh hoga 1 upon 8 so r upon 8r into v reference is 1 8 whatever the reference is each tap has this voltage which is the tap voltage I am saying if this is my reference potential r upon 8r is the voltage here is that correct so this voltage is essentially r upon 1 8r into v reference so this is essentially what do we say it is tap voltage so reference paach hain to 0.625 volt uska tap voltage so paela jo v1 hoga yaaapar sorry vulta baata main yaaapar yaaapar r upon 8r means 0.625 yaa 1.25 and to keep putting as many bits like for example v7 will be 7 by 8 into 5 which is 4.375 volts let us say v in is 3 volt let us say v in is 3 volt then what is the temperature code we are looking for 0s 8 bit 7 bit code by the way temperature codes are 7 bit code 2 to the power n minus 1 bit codes so it is 0 0 why it is 8th is not because 0 0 is always 0 0 so 8th is never used so 0 0 1 1 1 3 volt okay no sorry coded to binary see equivalent by code ka hoga 1 0 0 is 4 okay okay and this is essentially equal to 0 0 jitni yaa onge utnay once yaaapar yaaapar yaaaapar okay. So correspondingly C1 will be how much? 3 0 1 1 1, C2 as a, every time, as you are going to get VIN, it will compare and data will do 1 0 1 0, the 1 0 1 0 will come decode I repeat this each is a tap of 0.625 volt compared with VIN input, you will create 1s and 0s at the output, these data corresponding to VIN is then decoded out to a smaller value of data which is d 0 to dn minus 1 n bit code which you can create, this is called flash ADC. What is the why it is called flash? Anything which does simultaneously some things we call it flash okay, we call it flash. Any parallel circuit is therefore acting like a flash, anything in serial it acts like very slow because the output of first has to wait to become input of the next okay, so it will always be slow. So here we have flash ADC, only thing I must tell you the outputs you get here are temperature cores, this finishes analog circuit cores as I envisage for secondary class, I hope I have I tried my level best to enthuse you. So we finish whatever is required for opans, so what we started with basic circuit basic transistors, their models, then we say okay basic amplifiers theory of amplifications, we did discuss frequency response, then we say use it, can we increase gains or different this, so put an integration of that, so I fuse defants and I say why not use defam and other amplifiers I use to create even better amplifier which we call opans and then I say okay opans can be used in varieties of these linear and non-linear circuits, then I say okay if opans then I discuss much about feedbacks, then using feedback and this opans we say okay we can create oscillators and we say okay if we use opans with digital or some parts of this networks we can also create A to D and D to A converters, exactly.