HP 8901B Operation And Calibration Manual page 121

5-5
Modulation and Audio
Modulation
and Audio
___ _ _ _ _ _ ~ ~ ~
~
If
you need
to
know:
~~
Refer
to:
e
A
way t o measure
FM
bursts
.......
Tone Burst FM (5-5)
e
An easy way to measure the residual
modulation of a transmitter
........
Residual Modulation (5-6)
e
A
way t o measure S I N A D on
internally demodulated or external
audio signals..
......................
SINAD
(5-7)
e
A quick way to measure signal-to-noise Signal-to-Noise (5-7)
e
A
way to use the Ratio Mode to check
modulation flatness
.................
Modulation Flatness (5-8)
e
A way to measure frequencies above
1300
MHz using a spectrum analyzer
as a fixed-tuned receiver
............
SA Down-Conversion (5-8)
Tone Burst FM This procedure enables you to configure the
HP
8901B as a
Tone Burst receiver by setting a time delay between when the
HP 8901B senses an
RF
signal at its INPUT and when it enables
the output at the MODULATION OUTPUT/AUDIO INPUT port.
1.
Connect your transmitter (modulated source) to the
HP
8 9 0 1 B ' s
INPUT. Connect an audio counter to the MODULATION OUTPUT/AUDIO
INPUT port.
2.
Press the FM key on the
€IF'
8901B.
3. Select a detector, and if desired, Audio Filters, and
an FM
4.
Key on the transmitter. Allow the HP 8901B to range and
5. Press the RANGE HOLD key to hold
all ranges and tuning.
6. Key in 18." SPCL to set the time delay. Where NN equals the
De-emphasis filter.
tune automatically.
desired delay in milliseconds (from 1 to 99). (fir instance, if a
5 ms
delay is desired, enter 18.5 SPCL, if a 50 ms delay is desired, enter
18.50 SPCL.) The special function value will remain in the display.
7.
Key on the transmitter. The audio counter should display
the modulation rate present at the end of the delay period.