4-14.
PULSE MODULATION VIDEO FEEDTHROUGH TEST
NOTE
THIS TEST IS NOT APPLICABLE TO INSTRUMENTS EQUIPPED WITH
OPTION 006, DELETE PULSE MODULATION
Specification
Table 4-27.
Pulse Modulation Video Feedthrough Test Specification
1. Band 4 (>20.0 to 26.5 GHZ) only applies to the HP 8340B.
Description
NOTE
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:
P
=
10 log (V2/R/1 mW)
Where:
P
=
DUT RF output level minus 10 dB, and
R
=
SO Ohms.
Equipment
Pulse Generator
HP 8012B
Oscilloscope
HP 1741A
Adapters
APC 3.5 (f) to APC 3.5 (f)
HP/PN 5061 -5311
(1 required if DUT is HP 8340B)
Type N (in) to APC 3.S (f)
HP P/N 1250-1 744
(1 required if DUT is HP 8341 B)
SMA
(in)
to BNC (f)
HP P/N 12S0-1200
BNC Tee
(in)
(f) (f)
HP P/N 12S0-0781
10 dB
Attenuator
HP 8493C Opt. 010
Low Pass Filter (LPF)
HP P/N 913S-0260
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.
For CW mode and frequencies only:
Video Feedthrough
(VF/VP):
0.4 <2.3 GHz (Band 0):
<5% for output power levels =-i-8dBm
2.3
to 26.5 GHz (Bands
1~4)1:
=0.2%
HP 8340B/41B
Performance Tests
4-67