Smart squelch, Output level adjust, Test tone – Lectrosonics UCR211 User Manual

Page 5: Batteries, Power supply, Ucr211 block diagram, Uhf compact receiver, Rf module, Rio rancho, nm – usa

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

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

FILTER

LCD

Display

Panel

PILOT TONE

DETECTOR

FILTER

uP uP

AMP

2nd

VCO

2:1

EXPANDER

TREBLE

2:1

EXPANDER

BASS

23 KHZ

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

1st

VCO

Smart Diversity

Smart Squelch

2ND

MIXER

10.7 MHZ

FILTER

SYNTHESIZER

Filter

Digital

Squelch

Output

Level

Adjust

Squelch

Digital

Attenuator

2 (HI)

1 (COMMON)

3 (LO)

Rio Rancho, NM – USA