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PILOT TONE MUTE
The UCR211 uses a pilot tone muting technique in order
to protect against the reception of stray signals. The
Lectrosonics transmitter adds an inaudible signal, known
as the pilot tone, to the transmitted signal. The receiver
detects (and removes) the pilot tone, and is thus able to
identify the desired signal and mute all others.
When the receiver is powered up, receive audio is muted
unless a proper pilot tone is detected. The pilot tone
must be present for approximately one second before
the signal is accepted.
The PILOT TONE BYPASS mode is set from the main
window. In this mode, the received audio remains
unmuted regardless of the presence or absence of a
pilot tone. This mode is useful for locating a clear
frequency, since any potential interference may be heard.
It may also be used in situations where squelching
behavior is undesirable. The PILOT TONE BYPASS
disables the squelch, as described below.
TM
SMART SQUELCH
The UCR211 employs a sophisticated squelching
system in an attempt to deliver the cleanest possible
audio during marginal conditions of reception. Any
squelching system faces inevitable trade-offs: squelch
too much and valuable audio information may be lost,
squelch too little and excessive noise may be heard;
respond too rapidly and the audio sounds "choppy,"
respond too sluggishly and syllables or entire words can
be cut off.
RF MODULE
AMP
FILTER
ANTENNA
SWITCHING
uP uP
SYNTHESIZER
LCD
Display
uP
Panel
Smart Diversity
4
SAW
FILTER
244 MHz
IF AMP
FILTER
LC
Filter
HI-LEVEL
MIXER
1st
2nd
FILTER
VCO
VCO
FILTER
2
E PROM
Attenuation
Smart Squelch
The UCR211 combines several techniques to achieve an
optimal balance, removing distracting noise, without the
squelching action itself becoming a distraction. One of
these techniques involves waiting for a word or syllable
to complete before squelching. Another incorporates
recent squelching history and recent signal strength,
adjusting squelching behavior dynamically for the most
serviceable result under variable conditions. Using these
and other techniques, the UCR211 can deliver accept-
able audio quality from otherwise unusable signals.
In the PILOT TONE BYPASS mode, the squelch system
is disabled. Received audio remains unmuted at all
times with this setting.
OUTPUT LEVEL ADJUST
One of several setup screens is provided for adjusting
the audio output level in 1dB steps from -50 to +10dBu
using the UP and DOWN buttons on the front panel.
TEST TONE
The UCR211 provides a 1kHz audio test tone at the XLR
connector for level adjustment of connected equipment.
The level is adjustable from -50 to +10 dBu in 1 dB steps
to allow a precise match.
BATTERIES
The UCR211 operates on two 9V alkaline or lithium
batteries. Access to the battery compartment is gained
by lifting one end and turning the rear panel door. NOTE:
Do not use an alkaline
Standard or "heavy duty" batteries are not recom-
mended.
IF
FILTER
2ND
3RD MIXER
COUNTING
MIXER
AND
DETECTOR
10.7 MHZ
IF AMP
50KHz
LP FILTER
23 KHZ
XTAL
CONTROLLED
LP
FILTER
3rd
OSCILLATOR
VARIABLE
CUT-OFF
LP FILTER
PILOT TONE
DETECTOR
and
a lithium in the same unit.
UCR211
BLOCK DIAGRAM
2:1
Output
EXPANDER
TREBLE
Level
Adjust
Squelch
AUDIO
AMP
2:1
EXPANDER
BASS
Digital
Digital
Attenuator
Squelch
XLR
OUT
50
2 (HI)
2K
1 (COMMON)
2K
3 (LO)
50
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