User manual

Appendix A: Specifications
AM700 Audio Measurement Set User Manual
A-9
Table A-1: Analog Analyzer Specifications (Cont.)
Capabilities Description
THD + N Measurement
High Resolution Mode Residual THD + N (cont.)
On –4 dBu Input Range
400 Hz to 6.6 kHz
100 Hz to 400 Hz
20 Hz to 100 Hz
On –10 dBu Input Range
400 Hz to 6.6 kHz
100 Hz to 400 Hz
20 Hz to 100 Hz
At Full Scale At Full Scale –6 dB
0.003% 0.006%
0.0075% 0.006%
0.0125% 0.0075%
0.005% 0.010%
0.0075% 0.010%
0.015% 0.011%
THD + N is limited by the A/D distortion (primarily
3rd harmonic) near full-scale at frequencies
below 200 Hz. At –6 dB relative to FS, the
increase in distortion at low frequencies is much
less, typically 0.003% versus 0.0075% (FS) at
20 Hz. Under some conditions (measurements
below 200 Hz), it may be desirable to manually
set the input range one setting higher, sacrificing
6 dB of noise floor for better distortion readings.
The autorange circuitry optimizes dynamic range,
somewhat compromising distortion near full
scale.