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S:\Hp8960\E1962B CDMA 2000\Pi Release\Reference Guide\Chapters\cdma2000_meas_afan_desc.fm
Audio Analyzer Measurement Description
Audio Analyzer Measurement Description
How is an analog audio measurement made?
The Audio Analyzer can measure Audio Level (V), SINAD (dB), Distortion (%), and Audio Frequency.
Measurements are made through the test set’s front panel AUDIO IN connectors. When measuring a mobile’s
audio output, the audio signal may come from either an acoustic coupler or from a test interface connection to
the mobile’s audio circuitry.
See “Audio Analyzer Block Diagram” on page 41.
The AUDIO IN connectors feed the inputs to a floating-input differential amplifier, with each input having an
impedance of about 100,000 ohms to chassis ground. For best noise immunity, connect the audio signal and its
ground reference to the two input ports through shielded coaxial cables, or input the signal to the AUDIO IN
HI connector and ground the AUDIO IN LO connector’s center contact.
None of the analog audio measurement results are affected by the Amplitude Offset setting.
SINAD/Distortion State
Select On or Off to enable or disable the SINAD and Distortion measurements. When On, these measurement
results are displayed below the Audio Level measurement and the SINAD/Distortion Fundamental Frequency
must be entered to specify the audio frequency for the measurement (range: 100 Hz to 10 kHz). When Off, four
dashes are displayed in place of the measurement results.
Audio Frequency State
Select On or Off to enable or disable the Audio Frequency measurement.
Filter Type
• None - no filtering is provided (default).
• 100 Hz BW Band Pass Filter (Tunable) - The 100 Hz BW BPF Center Frequency setting is available when
this filter is selected, and can be set in the range of 300 Hz to 15 kHz.
• C-Message
• 50 Hz to 15 kHz
• 300 Hz to 15 kHz
Detector Type
Select either Peak or RMS (default) for making and displaying an Audio Level measurement (does not affect
other measurements). The type of detector selected is displayed next to the Audio Level measurement results.
A 1-volt rms sinewave input signal would measure 1.414 V
Peak
when the Peak detector is used. A 1-volt peak
input signal would measure 0.707 V
RMS
when the RMS detector is used.
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