Lectrosonics UCR211 - Manual (Page 5)

UHF Compact Receiver
identify the desired signal and mute all others. (If the
transmitter frequency differs from the receiver by as
much as one “notch” or 100kHz, the pilot tone indicator
on the receiver will drop out and the receiver audio will
mute.)
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.
SMART SQUELCH TM
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.
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
and a lithium in the same unit.
Standard or “heavy duty” batteries are not recom­
mended.
POWER SUPPLY
The UCR211 may be operated from an external DC
source (see Specifications and Features section for
allowed voltages.) The receiver has a built-in Poly-Fuse
to protect the unit. This fuse resets if the power supply is
disconnected for about 15 seconds. The power section
Attenuation
IF
FILTER
50
50
2K
2K
uP
LCD
Display
Panel
PILOT TONE
DETECTOR
FILTER FILTER
uP uP
AMP
2nd
VCO
2:1
EXPANDER
TREBLE
2:1
EXPANDER
BASS
23 KHZ
LP
FILTER
XLR
OUT
HI-LEVEL
MIXER
RF MODULE
3RD MIXER
AND
IF AMP
50KHz
LP FILTER
XTAL
CONTROLLED
3rd
OSCILLATOR
SAW
FILTER
244 MHz
IF AMP
COUNTING
DETECTOR
AUDIO
AMP
UCR211
BLOCK DIAGRAM
VARIABLE
CUT-OFF
LP FILTER
ANTENNA
SWITCHING
FILTER
E PROM 2
1st
VCO
Smart Diversity
Smart Squelch
2ND
MIXER
10.7 MHZ
FILTER
SYNTHESIZER
LC
Filter
Digital
Squelch
Output
Level
Adjust Squelch
Digital
Attenuator
2 (HI)
1 (COMMON)
3 (LO)
Rio Rancho, NM – USA 5