TB 9-6625-160-24
12. Distortion, Sinad and Signal to Noise Accuracy
a. Performance Check
(1) Press TI numerical key for 41.0 and then SPCL key to initialize TI.
(2) Connect equipment as shown in figure 3.
Figure 3. Distortion, Sinad and Signal/Noise Connection.
NOTE
For 8903B (S/N below 2742), use the impedance switch to set
the proper impedance. For 8903B (S/N 2742 and above),
47.0 SPCL sets impedance to 600 Ω and 47.1 SPCL sets
impedance to 50 Ω. Verify the IMPEDANCE light is either on
or off for 50 Ω or 600 Ω respectively.
(3) Set TI controls as follows in (a) through (d) below:
(a) INPUT/OUTPUT FLOAT
GROUND
(b) LOG/LIN
LOG
AMPTD
6V
(c)
50 Ω
(d) IMPEDANCE
(4) Set MULTIMETER to measure AC volts.
(5) Set RF REFERENCE SOURCE, FREQUENCY controls for first Applied Freq
listed in table 15 below.
(6) Set TI SOURCE FREQ (Hz) to first value listed in table 15 below.
(7) Set RF REFERENCE SOURCE, LEVEL to minimum.
(8) Record MULTIMETER indication.
(9) Set TI SOURCE AMPTD for 0 V.
(10) Set RF REFERENCE SOURCE, LEVEL for same MULTIMETER value
recorded in step (8) above (0.01 V).
