Figure 9. Connections for final testing.
a. Adjust the AMPLITUDE control on
20,000 cps and repeat the above procedure
the audio oscillator to obtain a reading of
f o r distortion measurement at this fre-
quency. Distortion should measure below
b. Set the spectrum analyzer function
1 percent. If distortion is below 1 per-
s w i t c h to SET LEVEL and the meter
range switch to 100% (10 volts). Adjust
spectrum analyzer (20 cps -20 kc), pre-
the spectrum analyzer signal INPUT con-
sume that is is low at higher frequencies.
trol to obtain a full-scale reading on the
e. Disconnect the audio oscillator from
0-1 scale of the spectrum analyzer volt-
t h e rf amplifier INPUT terminals, and
s h o r t the INPUT terminals on the rf
c. Set the spectrum analyzer function
a m p l i f i e r together with a wire jumper.
switch to DISTORTION and tune the FRE-
f. Set the spectrum analyzer function
switch to SET LEVEL and set the signal
R e d u c e the setting of the meter range
I N P U T control to MAX; set the meter
switch as necessary and tune the spec-
range switch to the .03 R.M.S. VOLTS
t r u m analyzer FREQUENCY and BAL-
range. The actual voltage input is now only
A N C E controls for a minimum meter
0.1 (one-tenth) of that indicated on the
reading. The distortion indicated by the
meter. The measured noise voltage should
meter must be less than 1 percent. If it
not exceed 3 millivolts.
is higher, measure the distortion in the
g. Set the amplifier GAIN switch to 20 db.
The spectrum analyzer meter should indi-
be less than 0.5 percent.
cate less than 2.5 millivolts.