R.V.R. Elettronica PTRL-NV/S3, Техническое руководство

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R.V.R. ELETTRONICA S.r.l. (BO) Pag. 39
PTRLNV/S3 - Technical and Maintenance Manual
1) Connect an audio frequency generator to the MONO or STEREO inputs.
2) Connect a 50 Ohm dummy load with a power rating of at least 10W to
the R.F. output.
3) Connect the R.F. input of the FM modulation meter to the output of
the wattmeter connected to the output of the PTRL-NV/S3.
4) Remove jumper J4 from the Main card.
5) Inject a 400 Hz signal at a level of -10 dBm (0.775 V
RMS
or 2.2 V
PP
peak to peak for american versions) into the MONO input (trimmer
R42 at maximum).
6) Set the STEREO/MONO-MPX selector (2 Fig.1) to MONO.
7) For american versions, inject the Mono signal at 0 dBm into the Mono
"+" and Mono "-" of the U.S.A. audio input card. Set the STEREO/
MONO-MPX switch to MONO and adjust R8 to annul the signal on
pin 14 of U2 (cmrr Common Mode Rejection Ratio).
Now, inject the mono signal at 0 dBm into the Mono "+" only (Mono
"-" is connected to ground).
8) Connect an oscilloscope to pin 14 of U1 (with R8 in a central
position) and adjust R40 for a reading of 8 V
PP
.
Set the STEREO/MONO-MPX switch (2 Fig.1) to STEREO, insert pilot
tone (5 Fig.1) and make the same adjustment using R37.
9) Configure the FM modulation meter to measure deviation with 75KHz.
If this is not the case, adjust trimmer R8 on the VCO for the right
value.
10) Inject a 400 Hz signal at a level of -10 dBm (0.775 V
RMS
or 2.2 V
PP
peak to peak for american versions) into the L and R inputs (trimmer
R41 at maximum).
11) Set the STEREO/MONO-MPX switch (2 Fig.1) to STEREO, insert pilot
tone (5 Fig.1) and fit jumper J3 to the Main card.
12) Connect an oscilloscope to pin 14 of U1 (with R8 in a central
position) and adjust R28 for a reading of 8 V
PP
.
13) Now remove jumper JP3 and fit it to JP4. Adjust R35 for 8 V
PP
.
NOTE: The audio generator used for this test must have a distortion level
of better than 0.001%.
Carry out this procedure at the normal operating frequency of the
transmitter