Shure UC1L Service Manual page 19

Deviation Reference Voltage: Using a Modified SC4 IF Receiver
NOTE: DC VOLTAGES ARE
PRESENT AT MOST RF TEST
POINTS. USE A DC BLOCK
ON THE RF SIGNAL GENERATOR
TO PROTECT TEST EQUIPMENT.
SC4 IF Receiver
Output: Unbalanced
Gain: Maximum
Squelch: Mid
Tone Key switch: OFF
Operating freq: See Table 2
Figure 10. Deviation Reference Voltage Test Set-Up,
Use the same Zad-1 mixer connections for the next adjustment test.
25A1043 (RI)
.
Deviation tests can also be performed using a modified SC4 IF
receiver. For instructions on modifying an SC4 receiver, consult the
Shure Service Equipment manual.
ZAD–1 MIXER
R
I
ANTENNA INPUT B
L
DC BLOCK
RF SIGNAL GENERATOR
Audio Analyzer
Measurement: AC level
Filters:
Low-Pass (30 kHz): ON
High-Pass (400 Hz): ON
Using a Modified SC4 IF Receiver
1. See Figure 10 for equipment test set-up and equipment settings.
2. Connect the rf signal generator output to the input port L (local
oscillator) of a Zad-1 mixer
3. Connect the output port I (intermediate frequency) of the Zad–1
mixer to antenna input B of the SCR IF receiver.
4. Turn the SC4 IF receiver ON and set the tone key switch on the
front panel of the SCR IF receiver to OFF.
5. Connect the audio voltmeter to the receiver's unbalanced output.
6. Measure the output voltage.
Record this voltage. This is the deviation reference voltage .
19
Shure UC1 Body-Pack UHF Transmitter
MODIFIED SC4 IF RECEIVER
TONE KEY SWITCH: OFF
AUDIO ANALYZER
Rf Signal Generator
Output Amplitude: + 7 dBm
AUDIO OUT
INT: FM
INT: 1 kHz
Frequency: 10.7 MHz
Modulation: See Table 2
Service Procedures