Specifications

2.24
Applications Manual
© 2003-2005 Prism Media Products Ltd
Revision 1.11Prism Sound dScope Series III
3.2.7.4 Power-line (mains) related products
Applies to:
EUTs with analogue or digital inputs and analogue or digital outputs.
Aim:
To measure power-line (mains) related products in the output noise of the
EUT
.
Method
If the EUT has a digital input, it is fed with a digital-zero signal; if the EUT has an analogue input it is
terminated with 50R (or 25R if unbalanced). The operator nominates either 50Hz or 60Hz power-line
frequency.
The RMS summation of the signal components in the EUT output at the power-line (mains) frequency
and its second through fifth harmonic is reported for both channels, in
dBFS
(in the case of an
analogue measurement, this is equivalent to dB below the specified
D/A line-up
).
Note: only components at the power-line (mains) frequency and its second through
fifth harmonics are included in this test. Artifacts from a high-frequency switching
power supply are classified as spurious components.
3.2.8 Cross-talk and separation
The Cross-talk and separation tests are arranged in the following subsections, which correspond to
the equivalent subsections of the AES17 standard:
Inter-channel cross-talk and separation
Non-linear inter-channel cross-talk
Input-to-output leakage
3.2.8.1 Inter-channel cross-talk and separation
Applies to:
EUTs with analogue or digital inputs and analogue or digital outputs.
Aim:
To measure the inter-channel cross-talk between the channels of the
EUT
at a range of
frequencies.
Method
This test is configured to measure interchannel cross-talk between the two
channels of a two-channel or stereo EUT. It can easily be adapted to measure iinter-
channel cross-talk for a larger number of channels, or separation between a number
of alternative inputs.
The input of the EUT's driven channel is fed with a sinusoidal stimulus at –20
dBFS
which is swept in
octave steps from 10Hz to the
upper band-edge frequency
. The input to the un-driven channel (if
digital) is fed with a digital-zero signal or (if analogue) is terminated with 50R (or 25R if unbalanced).
At each frequency, the ratio of the RMS amplitude of the output of the un-driven channel (measured
through a 1/3 octave band-pass filter at the stimulus frequency) to the RMS amplitude of the output of
the driven channel is measured, and displayed graphically in dB against frequency. The un-driven
and driven channels are reversed and the test is repeated. The two channels are overlaid on the
same axes so that worst-case cross-talk can be easily seen.