Audio Alignment - Shure U2 Service Manual

Shure U2 Hand-Held UHF Transmitter

Audio Alignment

Deviation Reference Voltage
RF SIGNAL GENERATOR
U4 Receiver
Output: Unbalanced
Gain: Maximum
Squelch: Mid
Tone Key (S201): OFF
Service Procedures
S201 (INSIDE U4)
DC
BLOCK
Audio Analyzer
Measurement: AC level
Filters:
Low-Pass (30 kHz): ON
High-Pass (400 Hz): ON
Figure 5. Deviation Reference Voltage Set-Up
1. Turn the U2 transmitter OFF.
2. Remove the cover of the U4 receiver to expose the pcbs.
3. Connect the rf signal generator to antenna port A or B on a U4
receiver. Make sure the dc block is on the rf signal generator.
4. Set the rf signal generator to the same frequency as the U2.
5. Set the rf signal generator internal FM tone to 1 kHz modulation.
6. Set the rf signal generator deviation to 45 kHz for UA, UB, MA,
MB, MC, and MD models; 40 kHz for KK models; and 5 kHz for
II models.
7. Set the rf signal generator amplitude to –50 dBm.
8. Turn the U4 receiver ON and set switch S201 inside the U4 to
the OFF position. This will disable the tone key function.
9. Set the output level of the U4 receiver to maximum.
10. Connect the voltmeter section of the audio analyzer to the
unbalanced output of the U4.
11. Verify that the voltage is 4.2 ± 0.5 dBu (1.26 ± 0.07 V) for UA, MA,
UB MB, MC, MD, and KK models, and –26.2 ± 0.5 dBu for II mod-
els. This is the deviation reference voltage.
12. Disconnect the rf signal generator from the U4 and move switch
S201 on the U4 to the ON position.
13. Turn OFF the rf output power from the rf signal generator.
16
U4 RECEIVER
AUDIO ANALYZER
Rf Signal Generator
INT: FM
INT: 1 kHz
Output Amplitude: –50 dBm
25B1022 (AG)