Service manual

166 8
Theory of Operation
SOURCE THEORY
• 8MHz (for A/D converter clock): is supplied to the A8 through the A20.
• 10MHz: is routed to the INT REF Output connector on the rear panel.
A2 Hc Amp.
The A2 Hc amp. produces a stable and accurate test signal. This signal is a CW or swept
signal between 40 Hz to 110 MHz, with a OSC level from 5 mV to 1Vrms/200 μA to 20
mArms. The 240 MHz signal from the A7 is applied to the mixer of the A2. It is then
converted to the CW or swept signal (40 Hz to 110 MHz) by mixing with the CW or swept
local signal ( 240MHz + fm : 240.00004 MHz to 350 MHz) from the A7.
The A2 Hc amp. has a DC bias source that provides constant bias voltage up to 40 V, and
bias current up to 100 mA.