Lectrosonics UCR211 User Manual
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UCR2
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DIVERSITY UHF RECEIVER
OPERATING INSTRUCTIONS
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LECTROSONICS, INC.
Rio Rancho, NM
www.lectrosonics.com
UCR211
LECTROSONICS, INC 2
UHF Compact Receiver
TABLE OF CONTENTS
GENERAL TECHNICAL DESCRIPTION............................................................. 4
DIVERSITY RECEPTION ................................................................................ 4
RF FREQUENCY TRACKING FRONT-END AND MIXER ............................... 4
MICROCONTROLLER, PLL AND VCO
CIRCUITS ........................................................................................................ 4
IF AMPLIFIERS AND SAW FILTERS .............................................................. 4
DIGITAL PULSE COUNTING DETECTOR ...................................................... 4
TRI-MODE DYNAMIC FILTER ......................................................................... 4
PILOT TONE MUTE ....................................................................................... 5
SMART SQUELCHTM ..................................................................................... 5
OUTPUT LEVEL ADJUST ............................................................................... 5
TEST TONE ...................................................................................................... 5
BATTERIES ...................................................................................................... 5
POWER SUPPLY ............................................................................................. 6
LCD DISPLAY .................................................................................................. 6
POWER UP SEQUENCE ................................................................................. 6
POWER OFF .................................................................................................... 6
FRONT PANEL CONTROLS AND INDICATORS ............................................... 7
LCD SCREEN .................................................................................................. 7
MENU BUTTON ............................................................................................... 7
SELECT UP/DOWN BUTTONS ....................................................................... 7
POWER ON/OFF SWITCH .............................................................................. 7
REAR PANEL FEATURES ................................................................................... 7
XLR AUDIO OUTPUT JACK ............................................................................ 7
POWER INPUT JACK ...................................................................................... 7
MAIN WINDOW (LCD) .......................................................................................... 8
MENU SELECTIONS FROM MAIN WINDOW .................................................... 9
FREQUENCY WINDOW .................................................................................. 9
BATTERY LEVEL WINDOW ............................................................................ 9
SETUP WINDOW ............................................................................................. 9
LEVEL ........................................................................................................ 9
TONE ......................................................................................................... 9
TTXBAT...................................................................................................... 9
FREQUENCY SCAN MODE ............................................................................... 10
SCAN AND VIEW WINDOW ELEMENTS ..................................................... 10
FINE VIEW WINDOW ELEMENTS ................................................................ 10
ANTENNA USE AND PLACEMENT.................................................................. 11
INSTALLATION AND OPERATING INSTRUCTIONS ...................................... 12
FINDING CLEAR FREQUENCIES ................................................................ 12
LOCKING AND UNLOCKING THE UCR211 FRONT PANEL CONTROLS .. 13
REPLACING THE BATTERY .............................................................................. 14
UCR211 REPLACEMENT PARTS and ACCESSORIES ................................. 15
TROUBLESHOOTING ........................................................................................ 16
SPECIFICATIONS AND FEATURES ................................................................. 17
SERVICE AND REPAIR ...................................................................................... 18
RETURNING UNITS FOR REPAIR.................................................................... 18
LIMITED ONE YEAR WARRANTY .................................................... Back Cover
Rio Rancho, NM – USA
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UCR211
GENERAL TECHNICAL DESCRIPTION
The UCR211 is a portable, high performance, tripleconversion, frequency synthesized, UHF receiver fully
compatible with all Lectrosonics 200 series transmitters.
The RF performance is extremely stable over a very
wide temperature range, making the UCR211 perfectly
suited to the rough environmental conditions found in the
field. The proprietary audio processing includes a dualband compandor for very low distortion and a superior
signal to noise ratio. The Smart Squelch system is
operated by a pilot tone and mutes the audio output
directly at the output connector.
The UCR211 features a menu-driven LCD graphic
display and a three button control panel as a convenient
means of viewing and altering user settings. The Main
Window, for example, shows the pilot tone indicator,
antenna diversity phase, RF level, audio level, receiver
battery status and transmitter battery status. It is also
possible to bypass the pilot tone from the Main Window.
Other display windows show operating frequency, audio
output level, battery status in tenths of volts, test tone
status and provide for selection of levels or functions
using the select buttons. The frequency scan mode
provides a graphical means of observing all signals “on
the air” within the frequency range of the receiver in
order to find operating frequencies that are free of
interference.
DIVERSITY RECEPTION
The UCR211 antenna phase diversity technology with
SMART DiversityTM minimizes dropouts in situations
where multi-path reflections can cause serious problems.
The phase diversity network and PIN diode RF switches
are controlled by the microprocessor using a sophisticated algorithm. This design keeps the receiver compact
enough for camera mounting or shoulder bag applications.
RF FREQUENCY TRACKING FRONT-END
AND MIXER
The receiver is frequency agile and can be set to operate
on any one of 256 frequencies within the tuning range.
To significantly reduce unwanted interference and
intermodulation problems, the UCR211 has a frequency
selective front-end section that tracks and tunes to the
desired signal frequency and rejects or “tunes out”
unwanted interfering signals. The design consists of four
varactor tuned ceramic transmission line resonators
controlled by the microprocessor to provide good selectivity. The low noise high current RF amplifier was
designed with feedback regulation for stability and
precise gain in order to handle stronger RF signals
without output overload. The first mixer is of new GaAs
technology that has a very high third order intercept
point. This produces a robust front-end that is as selective as fixed single frequency designs and is suitable for
use in close proximity to other receivers and transmitters
commonly used in field production “bag” systems.
MICROCONTROLLER, PLL AND VCO
CIRCUITS
The 8-bit microprocessor is truly the “heart” of the
UCR211 receiver. It monitors user command inputs from
the front panel control buttons and numerous other
internal signals such as RF level, audio levels, pilot tone
levels and external/internal power voltages. Outputs
from the microcontroller operate the front-end tuning,
PLL/VCO circuits, antenna phase switch, drive the LCD
display and backlight, and control the squelch and audio
output attenuator. The microcontroller also generates an
audio test tone used to adjust input levels of the equipment being fed by the receiver. The UCR211 design and
the advanced technology of the microprocessor control
arguably set a new standard in wireless microphone
development.
IF AMPLIFIERS AND SAW FILTERS
The first IF low noise amplifier is controlled with feedback regulation and drives the first of two quartz SAW
(Surface Acoustical Wave) filters. The 244 MHz SAW
filters combine sharp tuning, constant group delay, wide
bandwidth and excellent temperature stability, far superior to conventional LC filters. The 244 MHz first IF
signal is converted to 10.7 MHz, filtered through two
ceramic filters for sharp selectivity, then converted to 300
kHz in one integrated circuit.
DIGITAL PULSE COUNTING DETECTOR
The UCR211 receiver uses an elegantly simple, yet
highly effective digital pulse detector to demodulate the
FM signal, rather than a conventional quadrature detector. This unusual design eliminates thermal drift, improves AM rejection, and provides very low audio
distortion.
TRI-MODE DYNAMIC FILTER
The audio signal is passed through a “dynamic noise
reduction circuit” that automatically controls the audio
cutoff frequency. The cutoff frequency of this filter is
varied automatically by measuring the amplitude and
frequency of the audio signal and the quality of the RF
signal. The audio bandwidth is held only to that point
necessary to pass the highest frequency audio signal
present at a given moment. This results in a dramatic
reduction of the higher frequency “hiss” normally present
particularly with low RF signal levels. During passages
of high frequency audio content, this filter dynamically
passes the signals with no decrease in high frequency
content. This filter has proven very effective and is
totally transparent.
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
LECTROSONICS, INC 4
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 acceptable 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 recommended.
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
RF MODULE
ANTENNA
SWITCHING
uP uP
LCD
Display
Panel
Smart Diversity
FILTER
SYNTHESIZER
UCR211
BLOCK DIAGRAM
2:1
TREBLE
AUDIO
AMP
2:1
BASS
Output
Level
Adjust
Digital
Attenuator
Squelch
Digital
Squelch
XLR
OUT
50
2 (HI)
2K
1 (COMMON)
2K
3 (LO)
50
5
HI-LEVEL
MIXER
IF
FILTER
2ND
MIXER
10.7 MHZ
3RD MIXER
AND
IF AMP
XTAL
CONTROLLED
3rd
OSCILLATOR
COUNTING
DETECTOR
50KHz
LP FILTER
23 KHZ
LP
FILTER
VARIABLE
CUT-OFF
LP FILTER
PILOT TONE
DETECTOR
EXPANDER
EXPANDER
SAW
FILTER
244 MHz
IF AMP
AMP
LC
Filter
FILTER
uP
2
E PROM
FILTER
1st
VCO
Attenuation
Smart Squelch
2nd
VCO
FILTER
Rio Rancho, NM – USA
UCR211
also has protection circuits that prevent damage to the
receiver if a positive ground power source is applied.
LCD DISPLAY
The display has four main windows. Pressing the MENU
button rotates through each of these windows.
If the battery gets low on either transmitter or receiver, a
message will interrupt the display every few seconds and
flash a “LOW BATTERY” warning.
After power is turned off and back on again, the unit
defaults to the main window and to the most recent
frequency, audio level, transmitter battery type and
locked/unlocked status settings. These settings are
retained even if the batteries are removed.
POWER UP SEQUENCE
The power-up sequence consists of four messages that
appear automatically over a period of a few seconds
after the power is switched on.
1) LOCKED or UNLOCKED status
2) The name LECTROSONICS
3) The model number and firmware revision
4) The frequency block of operation
After these introductory messages are displayed, the
main window will appear.
The UCR211 is fully operational during the power up
sequence and will immediately respond to button pushes
made before the automatic sequence is completed. If a
valid transmitter signal is already present when the
receiver is turned on, the audio output will typically be
engaged somewhere in the middle of the power-up
sequence, following a brief delay to allow the audio
circuits to stabilize.
(See LOCKING AND UNLOCKING THE UCR211
FRONT PANEL CONTROLS.)
POWER OFF
When the power switch is moved to the OFF position the
audio output is instantly muted (squelched) and the
message “POWERING OFF...” is displayed briefly before
switching off.
LECTROSONICS, INC 6
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