OPTIMOD-FM OPERATION
4-13
Frequency THD+N Typical THD+N Maximum
50 Hz 0.015% 0.03%
100 Hz 0.015% 0.03%
400 Hz 0.015% 0.03%
1 kHz 0.015% 0.03%
2.5 kHz 0.015% 0.03%
5 kHz 0.015% 0.03%
7.5 kHz 0.015% 0.03%
10 kHz 0.015% 0.03%
15 kHz 0.015% 0.03%
H) Repeat the above measurements for the right channel. Connect the oscillator to the
right analog input and the distortion analyzer to the right analog output.
I) Disconnect the oscillator and THD analyzer from the 8400.
6. Test Digital Sample Rate Converter (Receiver).
A) Verify 8400 software controls are set to their default settings. (Refer to page 4-9.)
B) Be sure you are still in BYPASS mode [see step (3.F)].
C) Navigate to Input/Output. On screen Input/Output 1, Set Input To: Digital.
D) Connect the digital source generator to the AES/EBU Digital Input XLR connector
of the 8400.
E) Set the frequency of the digital source generator to 400 Hz and its output level to 6
dB below full scale.
F) Inject the Digital Input with a sample rate of 32 kHz, 44.1 kHz and 48 kHz. Use
24-bit words.
G) Listen to the analog outputs of the 8400 and verify that the output sounds clean and
glitch-free regardless of the input sample rate.
H) Leave the digital source generator connected to the 8400.
7. Test Digital Sample Rate Converter (Transmitter).
A) Set the sample rate of the digital source generator to 48 kHz.
B) Navigate to Screen Input/Output 2.
C) Connect an AES/EBU analyzer (like the Audio Precision System 2) to the 8400’s
AES/EBU digital output.
D) Change the Samp Rate to 32 kHz, 44.1 kHz and 48 kHz, and verify that the fre-
quencies measured at the 8400’s AES/EBU output follow the chart below within
given tolerances:
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