 Hello! In this video I will introduce you to the RED certification requirements for Bluetooth or energy devices and show you practical examples of RF measurements. All of these demonstrations are performed in conducted mode. I hope this video helps you to prepare your BLE device for true RED certification. At the beginning I will briefly introduce you to the RED requirements that must be met by the BLE device. I will show you the measurement of RF parameters of the transmitted signal and the signal in the received mode, as required by the standard. Based on the values found, you can assess whether your device achieves such properties that allow the device to be subjected to a real test in a certified laboratory. Based on the test performed, you can issue a statement that your device complies with the RED requirements. So, what parameters do we measure? It is the RF output power of the signal, power spectral density, which is the power distributed over a unit of frequency band. Furthermore, it is the occupied channel bandwidth that indicates whether the signal remains in the reserved band. In addition, besides the wanted signal, the device also produces its interfering emissions. These are measured in two categories, in the out-of-band domain and the spurious domain. As for the receiver, it is also found out spurs when the device is in received mode. Now I will introduce you to the basic requirements set by the Etsy for the evolution of equipment transmitting in BLE technology. The use of the radio device is regulated by RED directives in EU. The EU-European standardization body is Etsy. It deals with standards for testing and type approval of transmitters and receivers. So, BLE device must be compliant with European standard to could be sold in European markets specified by the document Etsy EN 300328. This standard defines two categories of equipment based on the modulation scheme. Frequency Hoping Spread Spectrum and other types of wide spectrum modulation. Etsy defines BLE device as DSSS, Direct Sequence Spread Spectrum, technology with adaptive system. Concurrently, BLE is classified with maximum power plus 10 dBm EIRP. Etsy defines different receiver categories based on maximum output power. According to this division, the receiver is considered as category second. It is non-adaptive equipment with a medium utilization factor greater than 1% and less than or equal to 10% or adaptive equipment with a maximum RF output power of 10 dBm EIRP. The devices must fulfill following requirements to be compliant with the Etsy. Maximum permitted output power is defined as mean equivalent isotropic radiated power during a burst and it is limited to a value plus 20 dBm. Power spectral density is mean equivalent isotropic radiated power spectral density during a burst and its value is limited by plus 10 dBm over MHz. Occupied channel bandwidth is bandwidth containing 99% of the signal. It must be completely inside the Bluetooth band 2400 MHz to 2483.5 MHz. Transmitted unwanted emissions in out-of-band domain are emissions appearing close to the allocated band when the device is transmitting. The band is specified by appropriatable. Transmitted unwanted emissions in spurious domain are emissions appearing farther from allocated band and the device is transmitting. The band and its limit is specified by a table. Receiver unwanted spurious emissions are emissions at any frequency that exceed given limit when device is in receiver mode. Receiver blocking is a measure of the ability of the equipment to receive a wanted signal on its operating channel without exceeding a given degradation in a presence of an unwanted signal. The minimum performance criterion is PER less than or equal to 10%. This parameter is not covered by this video. Here are listed the basic parameters we will deal with. First, a couple of remarks here. It is important to set the input of the spectrum analyzer, especially the input attenuator before each measurement. It is also necessary to set the signal display parameters correctly, because incorrect configuration will lead to incorrect conclusions. All measurements will be made at 1 Mbps, but similarly can be applied to 2 Mbps. The first set of measurements will concern the parameters of transmitter. We will start with measurement of RF output power. We will use spectrum analyzer and measure in conducted mode. We perform the measurements on three channels, low, middle and high. The signal must be a single tone modulated and analyzer must be capable of a minimum 1 Mbps. The output power limit is defined to be less than plus 20 dBm. Set reference level to 10 dBm and input attenuator to 20 dB. Enter center frequency, in this case 2402 MHz. We set a span at 4 MHz. Then we enter RBW at 1 MHz and VBW at 1 MHz as well. Detector to auto peak and trace on max hold. Sweep time will be auto, and we place the marker to peak. Because of conducted measurement, we need to add an attenuation of the cable and maximal gain of antenna. We get the EIRP value. The output power is therefore easily met by requirements. The next step is power spectral density. We will use a spectrum analyzer and measure in conducted mode. Measurements are again performed on three channels. Marker shows the spectral density just in 1 MHz, but we need to add cable loss and antenna gain to get EIRP value. Only then we can compare this with limit 10 dBm over the MHz. Enter center frequency 2402 MHz. We set a span at 3 MHz. Enter resolution bandwidth as 1 MHz and VBW at 3 MHz. Sweep time to auto. Detector to auto peak and trace on max hold. And placing the marker to peak, we can read its value. We write down the results in a table and compare them. We can see there is enough margin to the limit. Now we measure out occupied channel bandwidth. It is bandwidth that contains 99% of the signal. We will use again spectrum analyzer and measure in conducted mode. Measurements must be performed on two outer channels. Activate the function of occupied bandwidth and set 99%. Read the markers delimiting occupied bandwidth. We will use them to determine if signal comply with the Etsy requirement. I show you how to do it for low channel. Enter center frequency at 2402 MHz. Span is on 4 MHz. Resolution bandwidth put in 50 kHz. View bandwidth to 200 kHz. Sweep time must be slow. We put it to 1 second. Then we change detector to RMS and trace on max hold. Activate function occupied bandwidth. And after stabilization we can read 99% bandwidth and both markers. We write down all the markers and compare them with outer frequencies of Bluetooth band. We will now deal with unwanted radiation in out of band domain. Those are emissions in close to allocated bandwidth. They are resulting from modulation process. It is measured on zero span. It means in time mode. But before we look at the analyzer setting we need to understand following table. The Etsy defines two limits depending on frequency distance from allocated band. Emissions that falls within 2 MHz bend below and above allocated band with the limit of minus 10 dBm over MHz. And emissions that falls within 2 MHz bend below and above allocated band extended by 2 MHz on both sides with the limit of minus 20 dBm over MHz. This table also defines another band related to the spurious domain we will talk about later. Measurements are performed always on two outer channels. We put the spectrum analyzer to appropriate middle frequency. Let's see a table we will mention further. Span must be zero. We also need to set the sweep points and trigger mode to determine the value for comparison the marker to be set on maximum. Don't forget to cable loss and antenna gain. Here we go for center frequency 2396.5 MHz but similarly for the others. Resolution bandwidth to 1 MHz. View bandwidth at 3 MHz. Sweep point we set to 5000 and span must be zero. Detector to RMS and trace on max old. Then hit a trigger button and set the video trigger to show the running. Then place the marker to peak. Here are two pictures from previous measurements. As we set the RBW to 1 MHz we measure power spread out in 1 MHz. That's why we need to make two measurements bend by bend for each side and for each limit value. We always read out the maximum value found by peak marker. And this is how the resulting table looks like. They are stated also value 2.5 dB as sum up of attenuation of cable and antenna gain. Cause this value should be compared with the limits. The second part of unwanted emissions are spurs. These are unwanted frequencies outside the allocated bend when device is transmitting. As we will see on the following table there are several frequency ranges. Let's say from 30 MHz to 1 GHz and from 1 GHz to 12.75 GHz. There are different limits and different resolution bandwidth setting for own measurement. It should be sufficient to measure only for the outermost channel. However others may also produce spurs outside the allocated bend. Therefore it is good to check the remaining channels as well. So if we start with lower bend we perform it on two channels. Set the start frequency to 30 MHz and stop frequency to 1 GHz. We set the resolution bandwidth to 100 kHz and the view bandwidth is then 300 kHz. Set the detector to peak and trace to max hold sweep point should be larger than 19400. After the signal has stabilized we put the markers to all spectral lines that exceed or are close to the limit. Enter start frequency 30 MHz and stop frequency 1 GHz. Resolution bandwidth at 100 kHz. View bandwidth at 300 kHz. To add dynamics for reading let change the input attenuator to 10 dB. We put the detector to auto peak and trace on max hold and also sweep point to 20 000. Now we can place marker to peak. We see that in lower subband there are some GSM frequencies getting to the RF signal. The reason is that we are not operating in undisturbed environment but even these peaks are under the limit. Let's calculate nominal levels of these products although they weren't caused by a Bluetooth transmitter. So just for example it was measured in 100 kHz RBW. When adding cable loss and antenna gain we get EIRP value. All are deeply under limit of minus 36 dBm over 100 kHz. Now we focus on spores above 1 GHz. This measurement is very similar to previous one just in difference of frequency range from 1 GHz to 12.75 GHz. RBW is now equal to 1 MHz and VBW is 3 MHz. We had to modify C points accordingly to be equal or larger than 23 500. The limit is for all frequencies the same minus 40 dBm over 1 MHz. We have RBW at 1 MHz and VBW at 3 MHz. Enter start frequency 1 GHz and stop frequency 12.75 GHz. We enter sweep points as 24000. We put the detector to auto peak and trace on max hold. Now we can place all markers to each peak to read their levels. Ok here are some charts. The level of each spectral line that could reach the limit is measured by marker. In next step we will evaluate their real levels. The limit is defined as an absolute value. The results are in the following table. The EIRP value is already known value with cable loss and antenna gain. We identified several frequencies as harmonics. And so I marked them as multiplies of fundamental frequency. The rest are non harmonics. We assess only frequencies in spurious domain. It means under 2396 MHz and above 2487.5 MHz. So the products marked with stars are not our concern. Similarly we can do the same evolution on transmitter products for high channel. There is no surprise and nothing goes above the limit. We are getting to receiver parameters. The very similar measurement as for transmitter spurious emissions is this one. Actually with the same settings the device is only need to be in receive mode. Again it can be divided into two sub bands. So for the band below 1 GHz as mentioned the same settings. But the limit is now minus 57 dBm over 100 kHz. And all emissions close less than 6 dB. To the limit must be recorded and subsequently measured in time domain. Enter start frequency 30 MHz and stop frequency 1 GHz. And also sweep points to 20 000 resolution bandwidth at 100 kHz. View bandwidth at 300 kHz. And put the detector to auto peak and trace on max hold. We can place marker to peak now. Also in this case we have measured some GSM frequencies but let's evaluate them according to Etsy. We have to determine EIRP value and then to compare with limit minus 57 dBm but with a given margin 6 dB. In our case we don't need to do additional measurement due to we are under the limit even with 6 dB margin. Here are the plots we measured. The measurements should be made in such environment where no disturbing signals appear. We can see there is no other interfero on either GSM one. And for the second subband it means for band from 1 GHz to 12.75 GHz there is the same setting as for transmitter. The device is only needs to be in receive mode. The limit is defined as minus 47 dBm over 1 MHz. Enter starch frequency 1 GHz and stop frequency 12.75 GHz. We set RBW at 1 MHz and VBW at 3 MHz. We put the detector to auto peak and trace on max hold. Don't forget to set sweep points to 24 000. Hit the marker button and read the peak value. In the plots we can see a clear spectrum but when measuring the peak it sits on quite high level. Let's find out its level. Although it doesn't reach limiting value but it is inside 6 dB range. This product should be exactly evaluated by measurement in time domain. And that is all for the session. Thank you for watching, hope you enjoyed the video and see you next time. Bye!