ZHCU772 December 2021
Synchronized clocks are critical for multichannel systems. This section shows the multichannel synchronized clocking performance while measuring the channel-to-channel skew between the transmitter and receiver of the two AFE7950EVMs, respectively. The time-skew test is performed between the two channels of AFE7950EVMs at different frequencies operating in L and S band RADAR applications.
The skew of the transmitter channel is evaluated by measuring skew between the generated outputs of the DAC of each AFE in a high-speed oscilloscope. Table 2-5 shows the channel-to-channel skew at 8847.36-MHz DAC sampling frequency and the achieved skew was less than 5 ps for each output frequency.
| Operating Frequency | Measured Time Skew (ps) |
|---|---|
| 850 MHz | 4.4 |
| 1800 MHz | 5.3 |
| 2600 MHz | 5.4 |
The skew of the receiver channel is evaluated by calculating the phase difference between signals captured from each ADC of the AFE. Table 2-6 shows the channel-to-channel skew at a 2949.12-MHz sampling frequency. The measured time skew was less than 10 ps for each input frequency.
| Operating Frequency | Measured Time Skew (ps) |
|---|---|
| 840 MHz | 4.4 |
| 1750 MHz | 0.31 |
| 2610 MHz | 0.18 |
| 3700 MHz | 3.56 |
| 4910 MHz | 3.84 |