- Digital Hybrid Wireless™
- LCD with spectrum scanner
- Two AA Batteries or DC power
- SmartSquelch™ for noiseless muting
- 256 selectable UHF frequencies
- SmartDiversity™ for enhanced RF reception
- Compatibility with analog transmitters
- DSP-based pilot tone squelch
- Balanced XLR output
The UCR401 is a high performance compact UHF wireless microphone receiver for
mobile applications such as ENG and film production. The compact size, battery
and external power and rugged attached antennas are ideal for video camera
mounted. Unique DSP algorithms in the design provide full compatibility with all
Lectrosonics 400 Series Digital Hybrid Wireless™ transmitters and a variety of
analog transmitters from Lectrosonics and some other manufacturers. Power is
provided by two AA batteries, typically NiMH rechargeable types, or external DC
supplied via a jack on the rear panel.
Microprocessor control enables SmartSquelch™ and SmartDiversity™ advanced
reception techniques to minimize noise and dropouts in all conditions. The
receiver differentiates between close and distant operation and adjusts the
squelch threshold automatically. In environments with significant RF
reflections, the diversity switching activity optimizes the antenna combining
based upon an analysis of RF level and audio content.
Finding a clear operating channel is simplified with a choice of 256 frequencies
across a 25.6 MHz bandwidth. A built-in RF spectrum analyzer scans the entire
tuning range of the receiver and displays RF activity on the built-in LCD.
Signal strength of other signals in the vicinity is indicated and empty sections
of the spectrum are quickly identified with the graphical display. The analyzer
will scan the entire spectrum and display the results in about 25 seconds, so it
is very convenient to find a clear frequency in each new location.
The DSP generates a unique pilot tone frequency for each selected operating
frequency to simplify coordination in multi-channel wireless systems. This
eliminates the possibility of a valid pilot tone signal being passed to another
receiver via IM (intermodulation) products.
The UCR401 preserves compatibility with earlier Lectrosonics analog wireless
transmitters in addition to its native hybrid operating mode. The DSP emulates a
compandor when set for use with 100 or 200 Series, IFB transmitters and can even
be used with some models from other manufacturers. When operating in the native
hybrid mode with a Lectrosonics hybrid transmitter, there is no compandor in the
audio path, so audio quality rivals a hard-wired connection.
Conventional squelch design faces several compromises:
- Squelch too aggressively and audio may be lost.
- Squelch too little and excessive noise may be heard.
- Respond too rapidly and the audio will sound "choppy."
- Respond too sluggishly and entire words or syllables can be cut off.
SmartSquelch™ overcomes these problems by:
- Waiting for a complete word or syllable before squelching.
- Assessing recent squelching history and RF signal strength.
- Assessing audio content to determine available masking.
By adjusting squelching behavior dynamically under varying conditions, the
UCR401 delivers acceptable audio quality from otherwise unusable signals.
Microprocessor controlled antenna phase combining keeps the receiver small, yet
still able to deal effectively with multi-path dropouts. SmartDiversity™
analyzes both the incoming RF level and the RF level's rate of change to
determine the optimum timing for phrase switching and the optimum antenna phase.
This adaptive technique operates over a wide range of RF levels to anticipate
dropouts before they occur. The system also employs "opportunistic switching" to
analyze and then latch the phase in the best position during brief squelch
In order to increase the effective dynamic range of the system, the UCR401 is
equipped with a Smart Noise Reduction algorithm, which removes hiss without
sacrificing high frequency response. SmartNR™ works by attenuating only those
portions of the audio signal the fit a statistical profile for randomness or
"electronic hiss." SmartNR™ offers significantly increased transparency over the
sophisticated variable low pass filters used in previous designs. Desired high
frequency signals having some coherence such as speech sibilance and tones are
DSP-based Pilot Tone
The 400 Series system design uses a DSP generated ultrasonic pilot tone to
control the receiver audio muting (squelch). By sensing the pilot tone and
incorporating brief delays when the matching transmitter is turned on or off,
thumps, pops and other transients are successfully eliminat4ed.
The pilot tone frequency is different for each of the 256 frequencies in the
tuning range (frequency block) of a system, which simplifies the coordination of
multi-channel wireless systems. The DSP generated pilot tone system also
eliminates fragile crystals, allowing the receiver to survive shocks and
mishandling much better than older analog-based pilot tone systems. Coherent
signals such as speech sibilance and tones are not affected.
The UCR401 receiver is designed to operate with Lectrosonics 400 Series
transmitters and will yield the best performance when doing so. However, thanks
to the flexibility of digital signal processing, the CR401 can also be used with
Lectrosonics IFB, 200 and 100 Series and certain non-Lectrosonics analog
transmitters in special compatibility modes.
Digital Hybrid Wireless Architecture
This block diagram outlines the architecture of this Digital Hybrid
Wireless* receiver, starting with the front-end filter and ending with a
Front-end filters block high powered RF energy on nearby frequencies to
protect the receiver form interference from sources like television broadcasts.
After this filtering the signal is converted to the final 300 kHz IF frequency
though three stages.
A digital pulse counting detector recovers the encoded analog signal sent
from the transmitter. This signal is then filtered, converted into a digital
bitstream and sent to the DSP. The DSP then recovers the 24-bit digital audio
signal the was generated in the transmitter, which is then converted to analog
and delivered to the output stage.
*US Patent Pending
Front Panel and LCD Interface
Graphical icons indicate the status of all aspects of operation, including
RF and audio levels, diversity switching activity and the status of batteries in
the receiver and the transmitter being operated. Sub-menus and a variety of
screens provide access to all settings and adjustments.
The LCD is backlit for virility in dim lighting conditions and remains very
visible in direct sunlight. All menus and screens are accessed with three
buttons on the front panel.
RF Spectrum Analyzer
The RF spectrum for UHF wireless microphones and IFB equipment has become
increasingly crowded, due largely to the roll out of digital television
broadcasts and the reallocation of some spectrum for other services. More than
ever, it is critically important to able to find clear operating frequencies
wherever a wireless system is going to operated. A built-in RF spectrum analyzer
n the UCR402 addresses this situation.
An RF site scan and analysis can be conducted in less than a minute using the
LCD interface. Simply pressing all three white buttons on the control panel sets
the receiver into a scanning mode that sweeps the entire tuning range of the
receiver in just over 20 seconds. The results of the scan are graphically
displayed on the LCD showing the position and strength of RF signal detected,
and the clear sections of the spectrum.
A marker in the display is scrolled to an area where there is no activity and
the three buttons are pressed again. A message appears prompting the choice of
the new frequency selected by scrolling, or the return to the previous frequency
in place before the scan. When the frequency is selected, the display changes to
a screen showing the selected frequency and the switch settings used on some
transmitter models. The transmitter is set to the frequency and the system is
ready for operation.
Using the receiver itself to conduct a site scan is especially beneficial
because any RF signals that are the product of IM (intermodulation) that occurs
inside the receiver will also be displayed. An external spectrum analyzer can
accurately identify RF signals outside of the receiver but it will not include
A rugged, practical package
The receiver is powered by two AA batteries or from an external DC source
via a locking connector. NiMH rechargeable batters are economical and especially
effective because they provide extended operating time, which is consistent with
continuous or intermittent use.
Audio is delivered via a balanced XLR connector, adjustable from mic to line
level in 1 dB steps with the LCD interface on the front panel.
A machined aluminum housing and battery door are designed for heavy use in
field production. The battery door remains attached to the housing when opened.
Operating Frequencies (MHz):
614.100 - 614.300
||665.600 - 691.100
|Frequency Adjustment Range: 25.5 MHz in 100 kHz steps
|Channel Separation:100 kHz
|Receiver Type: Triple conversion, superheterodyne, 244 MHz,
10.7 MHz and 300 kHz
|Frequency Sustainability :±0.001%
|Front end bandwidth: 30 MHz @ -3 dB
20 dB Sinad: 1 uV (-107 dBm), A weighted
60 dB Quieting: 1.5 uV (-104 dBm), A weighted
|Squelch Quieting: Greater than 100 dB
|AM Rejection: Greater than 60 dB, 2 uV to 1 Volt (Undetectable
|Modulation Acceptance: 85 kHz
|Image and Spurious Rejection: 85 dB
|Third Order Intercept: 0 dBm
|Diversity Method: Phased antenna combining - SmartDiversity™
|FM Detector: Digital Pulse Counting Detector operating at 300
|Antenna Inputs: Two, fixed whip
|Audio Outputs: Rear Panel XLR adjustable from -50 dBu to +5 dBu
in 1 dB steps. Calibrated into a typical 10 k Ohm balanced load. Can drive
600 Ohm load.
|Front Panel Controls and Indicators:
LCD Control Panel
||Main Window: Pilot tone; antenna phase, receiver
battery level; transmitter battery status; audio level; RF level
||Frequency Window: Frequency, TV channel;
Transmitter Switch setting
||Audio Output Level Adjustment:
-50 dBu to +5 dBu
||Battery Level Tracking: 0.1V steps, accuracy +/-
0.2V, Timer option available for NiMH batteries.
|Scanning Mode: Coarse and fine modes for RF spectrum site
|Audio Test Tone: 1 kHz, -50 to +5 dB output in 1 dB steps; less
than 1% THD
|Transmitter Battery Type Selection: 9V alkaline, 9V lithium, AA alkaline, AA
|Phase Invert: Audio output phase
normal or inverted
|Smart NR (noise reduction): OFF, NORMAL, FULL modes
(available in 400 Series mode only)
|Audio Performance (overall system)
(These specs apply to 400 Series mode only.)
||Frequency response (Typical): 32 Hz to 20
kHz (+/- 1 dB) System frequency response varies depending on transmitter
THD: 0.2% (typical)
|| SNR at Receiver Output (dB):
Input Dynamic Range:125 dB (with full Tx limiting)
|Rear Panel Controls and Features: XLR balanced audio output jack; External DC
input; Battery compartment access.
|| External DC: Minimum 6 Volts to maximum 18
Volts DC; 1.6 W, 180 mA at 12V DC
|| Internal Battery: Two AA 1.5 Volt alkaline,
lithium or NiMH; 165 mA @ 9V, 240 mA @ 6V
||AA Alkaline: 5 hours continuous, up to 10 hours intermittent
||AA Lithium: Up to 20 hours (continuous and intermittent)
||AA NiMH (2500 mAH): 8 hours per charge typical (continuous
|Weight: 13 oz. (with
|Dimensions: 2.83" W x 1.25"
H x 4.64" D (2.83 mm x 32 mm x 118 mm)
Most users do not need a license to operate this wireless microphone system.
Nevertheless, operating this microphone system without a license is subject to
certain restrictions: The system may not cause harmful interference; it must
operate at a low power level (not in excess of 50 milliwatts); and it has no
protection from interference received from any other device. Purchasers should
also be aware that the FCC is currently evaluating use of wireless microphone
systems, and these rules are subject to change. For more information, call the
FCC at 1–888–CALL–FCC (TTY: 1–888–TELL–FCC) or
visit the FCC's wireless
microphone Web site.
If you're a licensed Part 74 operator, you may continue to use 50mW and greater
wireless systems under certain conditions. Eligible parties include a person or
organization engaged in the production or filming of motion pictures or
television, so, to the best of our knowledge, this includes below the line
More information on also can be found here.
To apply for a license, visit
If you have
any questions about these usage restrictions, please give us a call at
1-866-GOTHAM-8 or e-mail