Solidyne 2600 serie, Owner'S Manual

Page: 40 / 45

 If the “A- weighted” filter is not available, a simple RC filter
will be used, that attenuates 3 dB in 15 KHz. The mea-
sured noise will be between 5 and 7 dB above to the real
one.
5.1.12 Signal/Noise ratio
In the same outline of the previous point, connect the
audio generator at 1 kHz / + 4 dBm to the line input.
Connect to the output an audio level meter with “A”
weighting filter and an oscilloscope. Load the output
with 600 ohms.
Move the fader to -10dB position. Adjust the line level
preset until get +4dBm output and use this value as
reference for the measurement of noise. Replace the
generator by a resistor of 600 ohms and measure the
new output level. This value plus + 4dBm is the S/N
ratio.

This measurement result is the noise level in dBA.
5.1.13 Crosstalk
Connect the audio generator (+4 dBm; 1kHz), to an
left channel of a line input. Connect an audio level me-
ter with “A” weighting filter, an oscilloscope and a load
of 600 ohms to the left AUD output. Connect another
load of 600 ohms to the left PGM output. Select all
buses (LIN, PGM and AUD) in the module. All buses
in others modules must be out. Enable the module
pressing AIR. Move the fader to the maximum.
Change the level of the generator until obtaining
+15dBm in the AUD output. Change the position of
the audio level meter from AUD to PGM output. Verify
that the audio level is +15 dBm +/- 0,5 dB. Release
the PGM button and measure the residual level of
the signal. This level, referred to +15 dBm, is the
crosstalk between left audition and left program. Re-
peat for all the combinations of left and right program
with left and right audition. In the same way, the
crosstalk on PGM bus can be measured. Check it with
the console specifications.
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