B
–2
Appendix B
FIR Enhanced-Resolution-Filter Parameters
Resolution Increase
(Enhancement)
–3 dB Bandwidth
(
×
Nyquist)
Filter Length
(Samples)
0.5
0.5
2
1.0
0.241
5
1.5
0.121
10
2.0
0.058
24
2.5
0.029
51
3.0
0.016
117
With low-pass filters, the actual SNR increase obtained in any
particular situation depends on the power spectral density of the
noise on the signal. The improvement in SNR corresponds to
the improvement in resolution if the noise in the signal is white
— that is, if it is evenly distributed across the frequency
spectrum. If the noise power is biased towards high frequencies,
the SNR improvement will be better than the resolution
improvement. Whereas the opposite may be true if the noise is
mostly at lower frequencies.
SNR improvement due to the removal of coherent noise signals
— feed-through of clock signals, for example — is decided by
the fall of the dominant frequency components of the signal in
the passband. This is easily ascertained using Spectral Analysis.
The filters have a precisely constant zero phase response. This
has two desirable properties. First, the filters do not distort the
relative position of different events in the waveform, even if the
events’ frequency content is different. And second, because the
waveforms are stored, the delay normally associated with
filtering (between the input and output waveforms) can be
exactly compensated during the computation of the filtered
waveform.
All the filters have been given exact unity gain at low frequency.
Enhanced resolution should thus not cause overflow if the
source data is not overflowed. If part of the source trace were to
overflow, filtering would be allowed, but the results in the vicinity
Содержание 9300C Series
Страница 1: ...Operator s Manual LeCroy 9300C Series Digital Oscilloscopes Revision A January 1998 ...
Страница 8: ...1 3 billed for parts and labor related to the repair work and for shipping ...
Страница 18: ...4 1 4 Introduction to the Controls Two Channel Front Panel ...
Страница 19: ...4 2 Introduction to the Controls Four Channel Front Panel ...
Страница 92: ......
Страница 111: ...11 3 Dual Quad ...
Страница 112: ...11 4 Display Parameter s XY only ...
Страница 113: ...11 5 XY Single XY Dual ...
Страница 127: ...12 10 UTILITIES Protected will be displayed on the upper part of the grid whenever the medium is accessed for writing ...
Страница 138: ...12 21 Ø FLASH UPDATE Offering the Update from and Update Program menus illustrated next page ...
Страница 139: ...12 22 UTILITIES The full screen warning message shown when FLASH UPDATE has been selected ...
Страница 142: ...13 2 WAVEFORM STORE RECALL ...
Страница 182: ......
Страница 189: ...A 15 9344C Series 9350C Series 9354C Series 9354CTM 50 000x 9344CL 9350CL 9354CL 100 000x ...
Страница 200: ...A 26 Specifications FourChannelsCombined by PP094 Adapter Peak Detect OFF 4 GS s 400k 2M 8M One PP094 input ...
Страница 252: ...E 6 Appendix E ...
Страница 275: ...Index 9370C 9374C Series A 18 9384C Series A 24 Zoom menu 10 7 Zoom of Math Functions 10 1 ...