Am Signalmeter Calibration - Rotel Rt-925 Technische Anleitung

AM SignalMeter Calibration

1. Connect AC VT VM to Tape Out jack. And apply
1,OOOkHz signal (400Hz
Coil from AM Signal Generator,
input level until output
Eichun g desMW-Feldstärke-Messinstruments
1. Wechselstrom-Röhrenvoltmeter
gang anschließen. 1.000kHz-Signal (mit 400Hz 30%
mod.) vom MW-Meßsender in die MW-Antennenspule
einspeisen und den Antenneneingangspegel erhöhen,
bis das Ausgangssignal den Sättigungspunkt
Etalonnagedu S-métreAM
Brancher le voltmétre
1.
OUT. Appliquer un signal de I.OOOHz (400Hz 30%
mod,) å la bobine d'antenne AM
teur de signal AM et augmenter le niveau d'entrée de
I 'antenne jusqu'ä ce que le signal de sortie atteigne
Fig. 1-2. AM SignalMeter Calibration
Abb. 1-2. Eichung des MW-Feldstärke-Meßinstruments
Fig. 1-2. Etalonnage du S-måtre AM
FM IFandRFAlignmentProcedure
Instruments: FM Signal Generator, Oscilloscope and HD
Analyzer
Set Function Selector to FM AUTO position.
A. FM IF ALIGNMENT
1. Connect oscilloscope and HD Analyzer to Tape Out
jack (Left or Right). And tune the Dial to a position
where no broadcasting signal is coming in and receive
clean noise. Keeping this position, adjust the bottom
core of FM IFT L 103 so that pointer
the center of FM Tuning Meter.
2. Connect FM Signal Generator (FM SG) to FM antenna
terminals and receive 90MHz
Adjust the top core of L 103 to minimize distortion.
Receive weak signal at reduced FM antenna input
levels, and adjust FM IFT Tl (on Front End) so that
wave form on oscilloscope
form) is symmetrical.
B. FM RF ALIGNMENT
Note: To align this phase, FM Ant input level must be
kept -3dB of limiter Saturation.
1. Receive 90MHz (Mono
Stereo Signal Generator with receiver set at 90MHz
on dial scale. And adjust FM OSC coil LO (on Front
End) to obtain maximum
the same time adjust coil LR2, LR I and LA (on
Front End) to obtain maximum
Mod.) into AM Antenna
and raise antenna
signal reaches saturation
an den Tonbandaus-
erreicht.
électronique AC au jack TAPE
partir du généra-
needle rests at
signal from FM SG.
(noise appearing on wave
Modulation) signal from
deflection on scope. And at
sensitivity.
point. See fig. 1-2.
2. While in state of 1, adjust potentiometer
IF pcb (See fig. 1-1) so that Signa: Meter reads "91'
Siehe Abb. 1-2.
Nach dieser Einstellung das Potentiometer VR201 auf
2.
der ZF-Leiterplatte
das Feldstärke-Meßinstrument
le point de saturation.
Dans le méme temps, régler Ie potentiométre
2.
du pcb Fl (voir fig. 1-1) de facon que le S-métre
affiche 9
AM
Next, switch frequency to 106MHz and adjust FM
2.
OSC trimmer capacitor TCO (on Front End) for cor-
rect reception with the dial tuned to 106MHz. At the
same time, adjust TCR2, TCRI
maximum sensitivity.
Repeat steps 1 and 2 to obtain correct tracking and
3.
balanced sensitivity.
Caution: Bandpass Filters
porated in FM IF circuit are classified into 5
divisions according to their center frequencies.
It is thus necessary to use the same frequency
division
Divisions of bandpass frequencies are indicat-
ed by colored dots as shown in the following
chart.
Color
Red
Blue
Orange
FM
Black
White
6
(siehe Abb. 1-1) so justieren, daß
„9" anzeigt.
Voir fig. 1-2.
AT THE SATURATION
POINT, ADJUST VR201 SO
THAT THE NEEDLE
THE SIGNAL METER
CATES 9
ANT INPUT LEVEL —
and TCA to obtain
(X 101, 102 and 103) incor-
when replacing Bandpass Filters.
Center Frequency
10.70MHz
10.67MHz
10.73MHz
10.64MHz
10.76MHz
V R201 on
VR201
OF
INDI-
Tolerance
±30kHz