Advertisement
Model 8902A
Operation
Audio Distortion and Level
FUNCTIONS
AUDIO DISTN, 1 kHz DISTN, 400
Hz
DISTN, RMS, AUDIO INPUT, Special Function 30 (External
Audio RMS Level)
DESCRIPTION
Measure distortion on either internally demodulated audio signals or externally input signals with
fundamental frequencies of 1 kHz or 400
H z .
(The fundamental frequency must be within &5%
of the nominal 1 kHz or
400
Hz for accurate measurements.) Once selected, the measurement
frequency remains unchanged and is automatically activated each time the audio distortion (or
SINAD) measurement is selected.
Special Function
30.0
enables the instriiment to measure the true rms level
of
an external
signal applied to the MODULATION OUTPUT/AUDIO INPUT connector. (The connector is
automatically switched to fiinction as an input upon selection of Special Function 30.0. The true
rms level of the internal demodulated audio cannot be measured.) Connector input impedance is
nominally 100 kR. The maximum measurable input level is
4
Vrms.
PROCEDURE
To measure distortion on the demodulated audio signal, select AUDIO DISTN (Shift, FM).
To measure distortion on an external audio signal applied to the MODULATION OUTPUT/AUDIO
INPUT, select AUDIO DISTN (Shift, FM) and AUDIO INPUT. (Only the true rms detector can be
used for these measurements.)
To change the measurement bandwidth of the internally demodulat.ed audio signal, Select the desired
filter keys. (Refer to Audio Filfiir.s on page 3-207.)
If measurements are to be made on a
1
kHz audio signal, select
1
kHz DISTN (Blue Key, PEAK+). If
measurements are to be made on a 400
Hz
audio signal, select 400 Hz DISTN (Blue Key, PEAK-).
To measure the true rms level of an audio signal applied to the MODULATION OUTPUT/AUDIO
INPUT, select 30.0 SPCL.
HP-IB PROGRAM CODES
AUDIO DISTN=S2
AUDIO INPUT
=
AI
MODULATION OUTPUT
=
A0
1 kHz DISTN
=
D5
400
H z
DISTN
=
D6
LIN results
=
LN
LOG results
=
LG
mV units
=
M V
uV
units
=
UV
VOLTS units
=
VL
SPCL
=
SP
3-229
Advertisement
Chapters
