Pulse Modulation Video Feedthrough Test - HP 8340B Manual

4-14. PULSE MODULATION VIDEO FEEDTHROUGH TEST

THIS TEST IS NOT APPLICABLE TO INSTRUMENTS EQUIPPED WITH
OPTION 006, DELETE PULSE MODULATION
Specification
For CW mode and frequencies only:
Video Feedthrough
0.4 <2.3 GHz (Band 0):
to 26.5 GHz (Bands
2.3
1. Band 4 (>20.0 to 26.5 GHZ) only applies to the HP 8340B.
Description
Video feedthrough is any component of the pulse generator signal that
appears at the DUT's RF output connector.
The DUT is set to a CW frequency at 0 dBin and is pulsed using a pulse generator. The pulsed RF
output signal is fed through a 10 dB attenuator and a low pass filter that will pass only the low
frequency (video feedthrough) component of the modulation envelope. The video feedthrough is
measured using an oscilloscope. The measured voltage is related to the RF power by:
10 log (V 2/R/1 mW)
P
=
Where:
P DUT RF output level minus 10 dB, and
=
R SO Ohms.
=
Equipment
Pulse Generator
Oscilloscope
Adapters
APC 3.5 (f) to APC 3.5 (f)
(1 required if DUT is HP 8340B)
Type N (in) to APC 3.S (f)
(1 required if DUT is HP 8341 B)
SMA
BNC Tee
10 dB
Low Pass Filter (LPF)
Procedure
1. Connect equipment as shown in Figure 4-17. Attach the BNC tee directly to the DUT's PULSE
input connector. Allow a one hour warm up time.
HP 8340B/41B
Table 4-27. Pulse Modulation Video Feedthrough Test Specification
(VF/VP):
<5% for output power levels =-i-8dBm
=0.2%
1~4)1:
to BNC (f)
(in)
(f) (f)
(in)
Attenuator
NOTE
NOTE
HP 8012B
HP 1741A
HP/PN 5061 -5311
HP P/N 1250-1 744
HP P/N 12S0-1200
HP P/N 12S0-0781
HP 8493C Opt. 010
HP P/N 913S-0260
Performance Tests 4-67