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adc2:simulations:fft_freq_mismatch [2009/11/20 23:11]
szymon.kulis
adc2:simulations:fft_freq_mismatch [2019/03/08 14:08] (current)
Line 39: Line 39:
 | -1.22  |  -0.10  |  -60.0  |  -60.0  |   ​54.8 ​ | -113.2 ​ |   ​54.8 ​ |   ​60.0 ​ |  | -1.22  |  -0.10  |  -60.0  |  -60.0  |   ​54.8 ​ | -113.2 ​ |   ​54.8 ​ |   ​60.0 ​ | 
 | -0.61  |  -0.05  |  -66.0  |  -66.0  |   ​60.8 ​ | -119.2 ​ |   ​60.8 ​ |   ​66.0 ​ |  | -0.61  |  -0.05  |  -66.0  |  -66.0  |   ​60.8 ​ | -119.2 ​ |   ​60.8 ​ |   ​66.0 ​ | 
-| -0.37  ​| ​ -0.03  |  -70. ​| ​ -70. ​| ​  65. | -123. ​| ​  65. ​| ​  70. ​| ​+| -0.38  ​| ​ -0.03  |  -70. ​| ​ -70. ​| ​  65. | -123. ​| ​  65. ​| ​  70.2  |  
 +| -0.21  |  -0.02  |  -75.4  |  -75.4  |   ​70.2 ​ | -128.6 ​ |   ​70.2 ​ |   ​75.4 ​ |  
 +| -0.12  |  -0.01  |  -80.0  |  -80.0  |   ​74.8 ​ | -133.2 ​ |   ​74.8 ​ |   ​80.0 ​ |  
 +| -0.06  |  -0.01  |  -86.0  |  -86.0  |   ​80.8 ​ | -139.2 ​ |   ​80.8 ​ |   ​86.0 ​ ​| ​
  
 +{{:​adc2:​simulations:​fsim_diff_log.png|}}
 +
 +**remark** : 1%@20Mhz@16kp = 12.7 Hz
 +
 +**conclusion** : if we want to achive resonable measurement resutls for 10-bit ADC working @ 20 Mhz (and with 16k FFT len) input signal freq should not differ from ideal one more then ~1 Hz. 
 +
 +**conclusion 2 ** : reducing lenght of FFT (fbase is becoming larger) should relax this requirement (but also degrade precision of measurement)
/services/www/http/wiki/data/attic/adc2/simulations/fft_freq_mismatch.1258755095.txt.gz · Last modified: 2019/03/08 14:06 (external edit)