Shure Computer Headset User Manual page 7

USING THE AUDIO MUTE/ON SWITCH
When set to MUTE, the transmitter does not transmit audio signals from the
microphone to the receiver. Use the mute switch for brief pauses in dictation or
when you don't want the computer to receive voice commands.
NOTE: The audio mute/on switch does NOT turn off the transmitter. When set
to MUTE, the transmitter continues to transmit a carrier signal and draw power
from the battery. Always turn the transmitter off when not in use to conserve
battery power.
TRANSMITTER AUDIO GAIN ADJUSTMENT
The audio gain control on the transmitter allows you to decrease the audio
signal level coming from the headset. It is factory preset at the maximum set-
ting (full clockwise). In most circumstances, this control should not require ad-
justment.
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To decrease Audio Gain: Rotate the transmitter gain con-
trol counterclockwise with the supplied screwdriver. See
Figure 11.
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To Return Gain to the Factory Setting: Rotate the trans-
mitter gain control clockwise as far as it will go.
TRANSMITTER GAIN ADJUSTMENT
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R
FIGURE 11
RECEIVER SQUELCH ADJUSTMENT
Squelch is a circuit in the receiver that mutes audio output in the absence of
the desired transmitter signal. The squelch control on the TC3 receiver is
factory preset for optimum performance. No further adjustment is nor-
mally required. It is possible to adjust the squelch control setting to empha-
size either signal quality or system range. Adjusting the squelch control pro-
duces the following results:
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Turning the squelch control clockwise causes the receiver
to demand a higher quality signal (less noise before mut-
ing), but decreases operating range.
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Turning the squelch control counterclockwise allows a low-
er quality signal through (more noise before muting), but
increases operating range.
To return the receiver squelch control to the factory setting, rotate it to the
mid-range position (so the slot is vertical).
How the Shure Noise Squelch Improves System Performance
Conventional squelch circuits work on the basis of received rf (radio fre-
quency) signal strength. However, such circuits cannot discriminate between
noise and desired signals. When the wireless system is used in an environ-
ment where lots of rf noise is present, conventional squelch circuits can "open"
unexpectedly, sending loud bursts of noise through the receiver when the
transmitter signal is weak or turned off.
Unlike conventional wireless systems, all Shure Headset systems use a
noise squelch circuit that analyzes signal quality along with signal strength. A
special detector monitors the level of high frequency noise. When the transmit-
ter signal is strong, the noise level is low and the receiver sends audio through.
When the transmitter signal is weak or absent, the noise level is high and the
squelch circuit mutes the receiver. This virtually eliminates the possibility of
annoying bursts of noise coming through your receiver.
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