HP 437B - Page 17

HP 437B
11. Disconnect the DVM negative input lead from the Vrf connector on
the test power meter and reconnect it to chassis ground.
12. Press the PWR REF (SHIFTed (7_)) key to turn the reference oscillator
on.
13. Record the indication observed on the DVM as Vcomp.
Vcomp
14, Disconnect the DVM negative input lead from chassis ground and
reconnect it to the Vrf connector on the rear panel of the test power
meter. The DVM is now set up to measure V1 which represents the
power reference oscillator output level.
15. Calculate the value of V1 equal to | mW from the following equation:
Vi — Yo = Voomp — V (Vcomp)? — (10-8) (4R) (EFFECTIVE EFFICIENCY)
Where:
Vo = previously recorded value
Vcomp = previously recorded value
10-3 = 1 milliwatt
R = previously recorded value
EFFECTIVE value for thermistor mount at 50 MHz
EFFICIENCY (traceable to the National Bureau of Standards).
16. Remove the Power Meter’s top cover and adjust A4R114 (LEVEL) until
the DVM indicates the calculated value of V1.
ADJUSTMENTS 5-1]