Solidyne D 816, Руководство пользователя

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CHAPTER 5
- Specifications and testing -
5.1 Testings
The radio stations that have their own Technical De-
partment sometimes needs to carry out measurements
when receiving the console. Also some engineers esti-
mate convenient to make a general inspection every
some years, to verify if the specifications continues
being perfect.
The methods and comments that are given next refer to
the Technical Specifications that figure at the end of this
chapter.
Before starts any measurement, make sure that all
modules present the following conditions: PAN POT
controls must be at the center position. PGM, AUD,
and SEND buttons must be released; and AIR and
CUE must be off. Be sure the console is
properly
grounded and no RF is present at the measurement
Laboratory.
5.1.1 Microphone
Connect an audio generator to a microphone input.
Connect an audio level meter and an oscilloscope to
the PGM left output (then repeat with the right). Connect
a 600 ohms charge to the output.
Set the audio generator to 1 kHz -80 dBm. Select MIC
and PGM on this channel. Move the main fader to the
maximum. Increase the gain of the module until obtain
+4dBm at the output.
Move GAIN to the minimum. Change the generator to
-45 dBm. Move the fader until you verify that can obtain
+4 dBm without clipping at the output.
Change to the right input of this channel (or to another
channel) and repeat the procedure.
5.1.2 Line
Connect the generator to left input of a line channel,
with a level of -20 dBm at 1 KHz. Verify that the oscillos-
cope and audio level meter are connected to the left
PGM output. Select LIN and PGM in the channel under
test; move to the maximum the GAIN knob and move
the main fader until you verify that can 4 dBm at
the output.
Change the gain control to the minimum; and increase
the input level up to +18 dBm; move the fader until ob-
tain +4 dBm at the output without visible clipping.
Increase the gain with the main fader until obt15
dBm at the output. Use this value like reference. Con-
nect the balanced input in common mode joining both
signal terminals. Then, verify that the output level decre-
ase at least 40 dB. Change the test frequency to verify
the common mode rejection specification.
Repeat for the right input of this channel or for another
channel.
5.1.3 Aux Input
Connect the generator to the AUX left input. Select
AUX and repeat the procedure explained for the line
channels, with levels of -25 dBm and +4 dBm. Take in
mind that the common mode rejection isn’t applicable
for this input.
5.1.4 Balanced Outputs
All the measurements must be carried out in the same
way that the unbalanced outputs, but disconnecting of
GND the instrumental used and connect it between the
two balanced terminals.
Another possibility is to measure all in unbalanced
mode (only one pin),
adding 6dB to the results.
5.1.5 Gain
Connect a microphone input to an audio generator.
Connect the audio level meter and the oscilloscope to
the output. Charge this output with 600 ohms.
Adjust the generator to -80 dBm @ 1 KHz. Select MIC
and PGM in this channel. Move the main fader and the
gain knob to the maximum position. The difference
between the obtained output level and -80 dB is the
gain of the console.
5.1.6 Frequency Response
Connect the generator to a microphone input. Connect
an audio level meter and an oscilloscope to the output.
Load it with 600 ohms.
Change the audio generator to 1 kHz / -50 dBm. Select
MIC and PGM in the channel. Move the main fader to
the value -10 dB. Change the gain of the module or the
generator output until obt4 dBm at the output.
Swap the frequency between 20 and 20.000 Hz and
verify the frequency response.
SOLIDYNE D·816 broadcast console Page 27