Specifications

2.69

Applications Manual

Revision 1.11Prism Sound dScope Series III

Specification

Across the amplitude range, the THD+N for line outputs should be less than –60dBr and for

headphone or speaker outputs, less than –57dBr. Typically, the THD+N will decrease slightly for the

first 10 or 20dB and then reach a low, constant level.

5.2.1.9 Signal-to-Noise

dScope Configuration:

Signal to Noise Ratio Track 35.dsc

Track Number:

Corresponding AP Test File:

5_dnr

Duration:

60 sec

Test Signal Description:

200Hz, -60dBFS

Channels:

L, C, R, Ls, Rs

Description

This test measures the noise floor of the

EUT

relative to a notional nominal –20

dBFS

signal

amplitude. This is done in the presence of a small signal (200Hz at –60dBFS) so that the EUT cannot

mute its D/A converter.

Method

Play track 35 and then click the

[OK]

button to start the test.

The dScope measures the residual amplitude of all channels, after a 200Hz notch filter, band-limited

between 22Hz and 22kHz, and using a CCIR–2k weighting filter. N

ote that this test is performed as a

sweep against track time (even though it could actually be a single spot measurement) for

consistency with the Dolby test procedure.

The first part of the test measures the noise level for each channel with the Sub turned On and all

speakers set to "small". The second part repeats the measurements with the Sub turned Off and the

front speakers set to "large".