Thd+N Test; Analog In To Analog Out Thd+N Test; Crosstalk Tests; Analog In To Analog Out Crosstalk Test - Lexicon MPX 500 Service Manual

MPX 500 Service Manual
3. Connect the Left Output to the Distortion Analyzer.
4. Set the Analyzer for a 0dB reference (@1kHz).
5. Sweep the Oscillator from 20Hz to 20kHz and verify the level to be within +/- 1.0dBr through out the
sweep.
6. Move the cables to the Right Input/Output connections and repeat step 4 & 5.

THD+N Test:

These tests will verify the THD+N specifications of the MPX 500's Left and Right input to output circuitry.

Analog In To Analog Out THD+N Test:

1. Apply a 1kHz sinewave signal to the MPX 500 Left Input @ 6.904Vrms.
2. Connect the Left Output to the Distortion Analyzer.
3. Set the Distortion Analyzer to measure THD.
4. Enable the Low pass filters on the Analyzer (30kHz, 20kHz).
5. Verify the Left output, THD+Noise level on the Analyzer is < 0.005%.
6. Move the cables to the Right Inputs/Outputs connections and repeat step 5.

Crosstalk Tests:

These tests will verify the crosstalk specifications of the MPX 500's Left and Right input to output circuitry.

Analog In To Analog Out Crosstalk Test:

1. Apply a 1kHz sinewave signal to the MPX 500 Left Input @ 7.746Vrms.
2. Connect the Right Output to the Distortion Analyzer.
3. Enable the Low pass filters on the Analyzer (30kHz, 20kHz).
4. Sweep the Oscillator from 20Hz to 20kHz and verify the level to be >.245mVrms throughout the sweep.
5. Move the Input cable to the Right side and the Output cable to the Left and repeat step 4.

Dynamic Range Tests:

These tests will verify the Dynamic Range specifications of the MPX 500's Left and Right input to output
circuitry.

Analog In To Analog Out Dynamic Range Test:

1. Apply a 1kHz sinewave signal to the MPX 500 Left Input @ 7.746Vrms.
2. Connect the Left Output to the Distortion Analyzer.
3. Set the Distortion Analyzer for a 0dB reference
4. Remove the Input cable from the Left input.
5. Enable the Low pass filters on the Analyzer (30kHz, 20kHz).
6. Verify the Noise level at the Left Output is > -97dBr (.218mVrms); (-101 dBr typical).
7. Connect the 1kHz-sinewave signal to the Right Input of the MPX 500.
8. Move the Left Output cable to the Right Output.
9. Set the Distortion Analyzer for a 0dB reference.
10. Remove the Input cable from the Right input.
11. Enable the Low pass filters on the Analyzer (30kHz, 20kHz).
12. Verify the Noise level at the Right Output is > -97dBr (-101 dBr typical).
Repeat Tests @ 48K
Select Internal 48k Clock Source from System mode and repeat all of the above tests.

Digital I/O Functionality

This test will verify that the MPX 500 will pass a valid S/PDIF digital audio signal through its digital input and
output circuitry.
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