Audio Tests; Units That Pass; Verify The Matching Receiver; Check The Transmitter - Shure T2 Service Manual

Shure T2 Vocal Artist Microphone Transmitter

Audio Tests

Units That Pass

Preliminary Tests
A: Verify the Matching Receiver
1. Make sure that the receiver is turned off. Connect the signal
generator to the receiver through a 50 Ω cable. Tack-solder the
center conductor to the antenna input and ground the shield of
the cable to pcb ground. Turn on the receiver.
2. Set the signal generator as follows:
RF
Amplitude: –50 dBm
Modulation: 1 kHz
Deviation: 15 kHz
Frequency: T2 operating frequency
3. Connect the audio from the unbalanced output to the audio ana-
lyzer with a 3.3 kΩ load. Turn the Volume control all the way up.
4. Engage the 400 Hz and 30 kHz filters on the audio analyzer.
Verify the following:
S
For the T3 and T4 the audio level is 400 mVrms ("90 mV)
S
For the T4N the audio level is 626 mVrms ("120 mV)
S
thd = <0.75%
B: Check the Transmitter
1. Disconnect the signal generator from the receiver. Monitor the
receiver's unbalanced audio output with a 3.3 kΩ load and the
audio analyzer. Make sure the receiver's Volume control is at its
maximum setting.
2. Replace the microphone cartridge on the T2 with the test head.
Set the unit's Gain control to minimum and unmute the audio.
3. Inject a 775 mV, 1 kHz signal from the audio analyzer into the
adapter cable and verify the following:
S
the amplitude from receiver's unbalanced output equals
400 mVrms ("90 mV)
S
thd = <0.75%
4. Change the frequency of the audio generator to 100 Hz and dis-
engage the 400 Hz high-pass filter from the audio analyzer.
Verify that the audio level is –1.0 dB ("0.7 dB) relative to the
level measured in step 3.
5. Change the frequency of the audio generator to 10 kHz and re-
engage the 400 Hz high-pass filter. Verify that the audio level,
relative to that measured in step 3, is –3.5 dB, "2 dB.
If the system components pass these tests and the microphone is
good, then the system is functioning as expected and shouldn't require
tuning and alignment. Inform the customer that the product has retested
within specifications.
8 25C1018 (CC)