Lectrosonics UCR195 User Manual
UCR 195
COMPACT UHF RECEIVER
OPERATING INSTRUCTIONS
and troubleshooting guide
LECTROSONICS, INC.
Rio Rancho, NM
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Compact UHF Receiver
Table of Contents
INTRODUCTION TO THE 195 SYSTEM ................................................. 4
GENERAL TECHNICAL DESCRIPTION
UCR195 RECEIVER ............................................................................ 6
FRONT PANEL CONTROLS AND FUNCTIONS .................................... 8
REAR PANEL CONTROLS AND FUNCTIONS ...................................... 9
ANTENNA USE AND PLACEMENT ...................................................... 10
OPERATING INSTRUCTIONS ............................................................... 11
CR195 REPLACEMENT PARTS and ACCESSORIES ........................ 11
TROUBLESHOOTING ............................................................................. 12
RETURNING UNITS FOR REPAIR ........................................................ 13
SPECIFICATIONS AND FEATURES ..................................................... 14
LIMITED ONE YEAR WARRANTY ........................................ Back cover
Rio Rancho, NM – USA
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INTRODUCTION TO THE 195 SYSTEM
The 195 Series system was designed for the most critical
studio and sound reinforcement applications. The
system design represents a significant step forward in
wireless microphone technology. Every stage in the
entire audio/radio chain from transmitter input to receiver output was evaluated and analyzed to produce the
operating parameters and performance requirements for
this entirely new design. The audio system provides the
lowest distortion and best signal to noise ratio of any
wireless mic system ever built. The RF link is extremely
stable, providing the highest reliability and freedom from
drop outs and interference.
The UCR195 employs the most advanced circuit and
mechanical design ever applied to a wireless microphone
receiver. The audio processing is the finest quality
system ever developed for wireless microphone systems.
The UCR195 re-defines the state of the art in high end
wireless microphone receivers.
The entire radio/audio system was designed from a “cold
start,” utilizing all that has been learned thus far. Many
new types of IC’s and semi-conductors are available now
that were only ideas a few years ago. The UCR195
design takes advantage of these new devices.
UT195 TRANSMITTER
The UT195 hand-held transmitter design was the result
of considerable research. The RF and audio performance
of the transmitter was considered first, followed by an
analysis of the typical user’s needs and the practicality of
various design possibilities. The basic circuitry had to
accommodate any frequency in the VHF or UHF spectrums. The mechanical design had to provide a comfortable “feel,” yet be rugged, foolproof and easy to operate.
The operating features and functions faced several
contradictions in the needs of different types of users.
This led to the development of a very versatile design
wherein the transmitter can be configured for either “fool
proof” operation or to provide user control of the audio
level, metering and indicators. The final UT195 design
combines the benefits of superior performance, ruggedness, user convenience, and flexibility.
UM195 TRANSMITTER
The UM195 is a small belt-pack style transmitter which
can be clipped on the belt, slipped into a pocket, or even
taped to the user's body under clothing. It offers the
same high performance and wide deviation as the UT195
and is compatible with all of Lectrosonics' 195 series
receivers. The UM195 comes with a standard lavalier
microphone but practically any mic can be adapted to
work with this transmitter. The transmitter audio level
can easily be monitored and set from the from panel.
DUAL-BAND COMPANDOR
Compandors have long been a source of audible distortion in wireless microphone systems. The basic problem
is that when the full bandwidth of the audio signal is
processed by a single compandor, the attack and decay
times will always be a compromise. If the time constants are fast, high frequency transient distortion will be
low, but low frequencies will be distorted. If the time
constants are slowed down, low frequency distortion will
be low, but high frequency transients will then be distorted. The
195 system introduces a new approach to solving
this basic problem with compandors, called “dual-band
companding.”
There are actually two separate compandors in the 195
system, one for high frequencies and one for low frequencies. A crossover network ahead of the compandor
separates the frequency bands at 1kHz with a 6dB per
octave slope, followed by separate high and low frequency compandors. The attack and release times in the
high frequency compandor are fast enough to keep high
frequency distortion at an extremely low level. The low
frequency compandor uses slower time constants,
reducing low frequency distortion to well below that of a
conventional compandor.
75kHz DEVIATION
Wideband, 75kHz, of deviation improves the capture
ratio, signal to noise ratio, and AM rejection of a wireless system dramatically.
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Compact UHF Receiver
NO PRE-EMPHASIS/DE-EMPHASIS
The signal to noise ratio of the 195 system is high
enough to preclude the need for conventional preemphasis (HF boost) in the transmitter and de-emphasis
(HF roll off) in the receiver. Pre-emphasis and deemphasis in an FM radio system usually provides about
a 10dB improvement in the signal to noise ratio of the
system, but the high frequency boost in the transmitter
must be removed in a purely complementary manner or
else the frequency response of the original audio signal
will be altered.
Pre-emphasis can also cause distortion in the IF filtering
stage in the receiver, since the high frequencies have
been boosted, which increases the level of the harmonics
in the FM signal. As this signal is passed through the IF
filters in the receiver, distortion can be produced, most
noticeable at full modulation. De-emphasis cannot be
applied until the signal is converted into audio, so there
is no way around this problem short of eliminating preemphasis altogether. Neither of these problems occur in
the 195 system. The dual-band compandor in the 195
Series system essentially provides a dynamic preemphasis/de-emphasis function with extremely low
distortion.
EXCEPTIONAL THERMAL STABILITY
If temperature shifts cause the oscillators to drift, or
values to change in the detector, serious distortion will
result. The components in the 195 Series systems meet
very stringent tolerances for thermal drift. System
distortion in the 195 series remains at very low levels
over a very wide temperature range. This is especially
important in applications where the receiver and/or
transmitter must be operated near heat generating
devices, outdoors in direct sunlight, or with the receiver
mounted in an equipment rack.
Rio Rancho, NM – USA
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