LeCroy WaveSurfer 400 Series User Manual

4-6 Theory of Operation
HAM631
CH1b SIG
CH2b SIG
20RL2
CH1 signal
CH4a SIG
Differencial
HAM631
20RL1
2
CH2a SIG
CH3a SIG
21RL2CH4 ADC
21RL1
Channel combine mode
(CH1 & CH3)
CH3 signal
CH2 ADC
CH4 ADC
4 channels mode
CH2a SIG
CH1a SIG CH1a SIG
CH3b SIG
CH2 ADC
21RL2
2
CH1
Front
End
CH1 ADC CH1 ADC
CH4
Front
End
HAM631
CH3
Front
End
20RL2
CH3 signal
HAM631
CH4
Front
End
CH3 signal
CH4a SIG
CH2
Front
End
CH2
Front
End
CH1 signal
2
HAM631
21RL1
CH1b SIG
CH3
Front
End
CH2 signal
CH4 signal
2
HAM631
CH2b SIG
CH1 signal
CH3 ADC
20RL1
HAM631
CH3b SIG
Differencial
CH4b SIG
CH1
Front
End
CH4b SIG
CH3 ADC
CH3a SIG
HAM631
Figure 4-6 4 & 2 Channel Mode
4.2.3 Trigger
HTR420
The main function of HFE420 are:
• Generation of trigger signal (analog input and digital output) with comparator
• Setting of trigger level (TRIG,VALIDATE)
• Setting of trigger coupling (DC,AC,LFREJ,HFREJ,HF)
• Setting of slope (+,-,WINDOW)
The different trigger couplings using HTR420 are :
• DC
• AC : cut off frequency is almost 7.5 Hz.
• LF REJ : single pole high pass filter with a cut off frequency at 50 kHz.
• HF REJ : single pole low pass filter with a cut off frequency at 50 kHz.
• HF : frequency divider by four for high frequency signal.
TV Trigger
Each channel has a pick-off after the HTR420. Selected trigger source goes to
commercial chip (LM1881) via AGC amplifier and provides three outputs
(Composite Sync. Output, Vertical Sync. Output, and ODD/EVEN output) to the
MST429A.

LeCroy WaveSurfer 400 Series Specifications

General

Brand	LeCroy
Model	WaveSurfer 400 Series
Category	Test Equipment
Language	English