 Hello everyone, this is Dr. Rupali Shalke working as an Associate Professor in Electronics Department at Wolchen Institute of Technology, Sholapur. In this video lecture, we are going to discuss on Moving Target Indicator Radar System. Learning outcomes, after completion of this video lecture, students are able to draw and explain a block diagram of Moving Target Indicator Radar System. Also, examine the parts and working of each block of the MTI Radar System. Before starting with the explanation of the Radar MTI Radar System, let us recall what is Doppler Effect, which we have discussed in the previous lectures. Doppler Effect, when a target is moving relative to the radar, it will result in an apparent shift in the carrier frequency. This effect is known as a Doppler Effect. Carrier frequency is nothing but a transmitting frequency, which is transmitted from the radar system towards the target. If there is a change in this transmitted frequency, that frequency change is given known as a Doppler Effect. When using this Doppler Effect, we can utilize in a pulse radar system by the combination of some special delay line and a new technology or improved radar system is developed, which is known as an MTI Radar System, in which the advantage or a feature of the MTI Radar System is that they can identify the velocity of the target, which is moving as well as they are able to distinguish between the stationary target and the moving target. Let us see, this is a block diagram of the MTI Radar System, which is consist of a transmitter and receiver. There are different components in this block diagram. There are the two oscillator, STALLO and COHREN. The STALLO stands for a stable local oscillator and COHREN stands for coherent oscillator. The STALLO generates a frequency known as F0 and COHREN oscillator generates the frequency known as FC. Here it is using the two mixers, mixer 1 and mixer 2. The characteristics of the mixers are same. The mixer 2 is used for the summing the signals and mixer 1 is used for differentiating the signal. There are two amplifiers, amplifier 1 and amplifier 2, which are having the same characteristics. Also it consists of IF amplifier, phase detector circuit, delay line, radar display, suppressor circuit, castron amplifier, duplexer and antenna. Now let us see how the working of this MTI Radar System takes place. The signal generated from the two oscillator that is STALLO and COHREN oscillators are given as an input to the mixer 2, where it sums the two signals and gives the output as F0 plus FC. This F0 plus FC generated signals will acts as a transmitting signal from the transmitter. This is fed to the multi-cavity castron amplifier, with this amplifier increase the power strength of the signals to the high power and then it is fed to the duplexer to the antenna. The signals are then transmitted into the free space towards the target through this antenna. The received ECO signals are received in a form of duplex antenna and then fed to the duplexer to the mixer 1. The function of the mixer 1 is to superheterodyne the received ECO signals with the signal generated from the STALLO amplifier. The mixer 1 differentiates the two signals and gives the output as an FC. The FC is fed again to the IF amplifier which amplifies the received signal. The amplified output is a FC output which is fed to the phase detector circuit. The one more input to this phase detector is from the COHRENT local oscillator. The phase detector output compares the two signals that is received signals and the signals receiving from the COHRENT oscillator. The COHRENT oscillator frequency is similar to the IF frequency therefore, it is also known as the COHRENT oscillator. The output of the phase detector depends upon the difference of these two frequencies or to these signals. Then all the received signals the detector circuit will use the signals or gives the output depending upon the changing of this received signal and the input signal. The output of the phase detector gives the output in a form of change in the phase as well as the change in the amplifier. The change both fixed as well as the moving target. If it is output of the fixed target then there is a no change in the phase and the amplitude of the signal. While as if it is the output of the received eco signal then or a received moving signals then there is a change in the frequency. That frequency change is due to the Doppler effect. That Doppler frequency change will change the change in the amplitude as well as a phase of the signal compared with the transmitted signals. And the shift in the frequency is of a half of the wavelength is a circuit whose time duration is related to the PRF that is pulse repetitive frequency which is a width of the pulse which depends upon the width of the pulse and that duration delay is been placed. The output of the phase detector depending upon the change in the phase are fed to the delay line circuit. The output of the phase detector is fed from the delay line to the amplifier 1 and then to the suppressor circuit. And similarly at the same time a undelayed output is fed to the amplifier 2 and then it is also connected to the suppressor circuit. The output of the suppressor circuit compares the 2 input signal. If you let us explain this for the fix as well as for the moving target. Now if you see the signals of the waveforms this is a waveforms which is a width on a y axis it is representing the amplitude on the x axis it is representing the time duration. The pulses which are being fed are the transmitted pulses. Now the pulses indicated by the numbers 1 and 2 are this are due to the fix target therefore when these 2 signals are fed to the suppressor circuit the output of the suppressor will cancel out because at they give the same input to the suppressor at with the same duration of time and therefore they get cancel out at the suppressor circuit this indicate that these 2 pulses are received from the fix target further if we observe that the pulses received from the at a 3 and 5 are delayed by the 4 at the delayed by delayed by the delayed line at a 4 and 6 respectively there is a delay in the signal when that 2 signals are fed to the suppressor circuit the output of the suppressor circuit will be in the change in the phase which indicate that this received signal is from the moving target indicator. This this effect or output of the suppressor circuit is then fed to the radar display circuit. Now if we see that we are already discussed with the continuous radar systems and the moving target indicator which both are working on the principle of the Doppler effect. Think for pause the video think for a while what is the difference between the continuous radar systems and the MTI radar system these are the reference book. Thank you.