PERFORMANCE TEST
4 - 19
4.3.16
Vertical deflection; common mode rejection ratio at 1 MHz
The common mode rejection ratio (CMRR) is a measure of susceptibility to
common mode signals. This susceptibility is verified in this test.
Test equipment:
Fluke 5500A mode: levsine (Alternative: HF constant amplitude sine wave
generator SG 503).
Power splitter
Test set up:
Settings/procedure:
1
-
Use a power splitter and two cables of equal length to CH1 and CH2.
Apply a 2 MHz sine-wave signal of 1.6 V(pp into 50
Ω
) to inputs CH1 and CH2.
2
-
Press the AUTOSET key.
3
-
Use 50
Ω
terminations. Use the internal terminations when available (via
VERT MENU key).
4
-
Set CH1 and CH2 to 0.1V/div and adjust the generator voltage for a
deflection of 8 divisions.
5
-
Set CH1 and CH2 to DC input coupling.
6
-
Press the CH1+CH2 key to activate the ‘added’ mode.
7
-
Press the INV key of CH2; the result is the display of CH1-CH2.
8
-
Press the ON keys of CH1 and CH2; this switches CH1 and CH2 off and
only the differential signal (CH1 CH2) is now visible.
9
-
Readjust the VAR function of CH1 or CH2 for minimum amplitude.
Requirements
-
Verify that the trace-height of the CH1-CH2 differential signal is less than 0.08
divisions.
Repeat the above settings and procedure for CH3 and CH4 (for PM3384B and
PM3394B only).