Keysight U8903B, Service Manual

Page: 79 / 165

Performance Verification for Digital Generator and Digital Analyzer 4
Keysight U8903B Service Guide 79
– SINE waveform amplitude: 1 FFS
– Digital output state: ON
4 Configure the U8903B digital input channel to be tested as follows:
– Digital input type: Unbalanced
– Digital input impedance: 75 Ω
– Digital measurement sample size: 16384
– Input coupling for both channel D1 and D2: DC
– Voltage detector for both channel D1 and D2: RMS
– AES audio format: LPCM
– Channels D1 and D2 FUNCTION1 to measure frequency
– Channels D1 and D2 FUNCTION1 to measure Voltage AC
5 Set the U8903B calibration digital output mode to BCOM mode for AES/SPDIF.
6 Set the digital output sampling rate F
SR
as given in “ Test record for unbalanced input
sampling rate accuracy verification ” on page 155 .
7 Set the frequency counter to measure the frequency of the output signal and record the
measurement as F
measure
.
8 Compute the sampling rate, F
SR_FC
based on the frequency counter measurement value
using the following equation.
F
SR_FC
= F
measure
/ 64
9 Record the F
SR_FC
values in “ Test record for unbalanced input sampling rate accuracy
verification ” on page 155 .
10 Repeat step 6 to step 9 for the rest of the F
SR
as given in “ Test record for unbalanced
input sampling rate accuracy verification ” on page 155 to complete the verification of
the different output sampling rates.
11 Connect the U8903B unbalanced digital output to its own balanced digital input using
the SPDIF or 75
Ω
impedance cable as shown in Figure 4-8 .
Figure 4-8 U8903B unbalanced digital output to its own unbalanced digital input for unbalanced input
sampling rate accuracy verification
U8903B
Unbalanced
digital output
Unbalanced
digital input
SPDIF or 75 Ω
impedance cable