Signal To Quantization Noise - H Heuer Instruments UMDT51A User Manual

Signal to Quantization Noise

1. Make the connections between the Test circuit and the LT51 as in Fig. 3.1.
2. Turn the LT51 ON. [after Reset: Ztx = 600, Zrtx = HiZ 600, TX Source =
OFF, TX Freq =10 kHz, Mode = TX-RX (4W)]
3. Press the
LT51 RTX (input) impedance is now 600  terminated.
4. Press the
Use the knob to set the span to 4.5 kHz.
Press the [f3] soft-key to set BW to 'PSOPH' to make psophometric
5.
weighted measurements.
6. Press the
'SINE'.
Press the [f4] soft-key to set the TX Freq to 1014 Hz using the Knob or
Keypad, and press the
[fx] soft-key if using keypad.
7. Press the
'S/ND' (Signal to Noise and Distortion) measurement, which is equivalent to
the S/Nq measurement.
8. Repeat for all levels at the steps in the Specification template.
9. The display will show the Psophometric weighted Signal to Quantisation
Noise ratio measured at the LT51 RTXab input terminals. Press
(Spectral) or
LT51 User Manual
button, then the [f2] soft-key to set Input to 'Term'. The
key, followed by the [f1] soft-key to set the frequency Span.
key followed by the [f3] soft-key to set the TX Source to
button to clear the Dialog box, or appropriate
key, followed by the [f1] soft-key to set Level to make a
(Numerical) to toggle between displays of the signal.
Testing VF-PCM Multiplexers
15