Shure UC2 Service Manual page 17

Deviation Reference Voltage, Using a UC4 or U4S Receiver
UC4 RECEIVER (BACK)
AUDIO ANALYZER
UC4 Receiver
Output: Unbalanced
Gain: Maximum
Squelch: Mid
Tone Key (S501): OFF
Group switch: See Table 2
Channel switch: See Table 2
25A1044 (RI)
Deviation must be set to make sure the companding systems be-
tween the transmitter and receiver correctly track each other. The level
coming out of the transmitter's audio compressor must match the level
going into the receiver's audio expander. A fixed gain structure does not
ensure an exact match, primarily because of variations in voltage-
controlled oscillators (VCOs).
This test requires a UC4 or a U4S receiver and is designed to tune
the transmitter regardless of the accuracy of the receiver's tuning. It is,
however, recommended that a properly-tuned receiver be used to per-
form the transmitter deviation adjustment.
DC BLOCK
RF SIGNAL GENERATOR
Audio Analyzer
Measurement: AC level
Filters:
Low-Pass (30 kHz): ON
High-Pass (400 Hz): ON
Figure 9. Deviation Reference Voltage Test Set-Up,
Using a UC4 or U4S Receiver
1. Connect the rf signal generator to one of the receiver's
antenna port B.
2. Turn the UC4 or U4S receiver ON.
3. Set the receiver frequency to match the transmitter frequency.
4. Set the rf signal generator frequency to match the transmitter
frequency.
5. Modulate the generator frequency with 1 kHz audio at a
–60 dBm output level. See Table 2 for deviation.
6. Set the tone key switch (S501 for the UC4, S201 for the U4S)
to the OFF position.
7. Connect the ac voltmeter to the unbalanced output of the
receiver.
8. Read the ac voltage.
Record this voltage. This is the deviation reference voltage .
17
Shure UC2 Hand-Held UHF Transmitter
UC4 RECEIVER (FRONT)
A B
SQUELCH
NOTE: DC VOLTAGES ARE PRESENT
AT MOST RF TEST POINTS. USE A
DC BLOCK ON THE RF SIGNAL
GENERATOR TO PROTECT
TEST EQUIPMENT.
Rf Signal Generator
Output amplitude: –60 dBm
S501
(TONE KEY SWITCH)
TK ON TK OFF
INT: FM
INT: 1 kHz
Frequency: See Table 2
Modulation: See Table 2
Service Procedures