Lectrosonics R400A User Manual

R400A

Digital Hybrid Wireless™ Diversity Receiver

SmartDiversity™

Microprocessor controlled antenna phase combining keeps
the receiver small, yet still able to deal effectively with multi­path dropouts. SmartDiversity™ analyzes both the incoming
RF level and the RF level’s rate of change to determine the
optimum timing for phase 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

• Digital Hybrid Wireless Technology

™

• SmartTune

• SmartDiversity

auto frequency selection

™

enhanced reception

• 256 selectable UHF frequencies

• Low Noise, High Gain RF Front End

• Independent Balanced XLR and Unbalanced
1/4 inch audio outputs

• Compatibility with analog transmitters

The R400A is a high performance table-top UHF receiver fully
compatible with all Lectrosonics 400 Series Digital Hybrid
Wireless™
transmitters and IFB transmitters, plus some analog transmit­ters from other manufacturers (call Lectrosonics for details). It
features 256 user selectable frequencies, and its proprietary
audio processing includes a digital signal processor (DSP) for
very low distortion, a superior signal to noise ratio and two
independent audio outputs, one balanced and one unbal­anced.

The receiver features a menu-driven graphic LCD display as a
convenient means of viewing and altering user settings.

transmitters, 200 Series and 100 Series analog

SmartTune™

A major problem facing wireless microphone users is finding
clear operating frequencies, especially in RF saturated
environments. SmartTune™ effectively overcomes this
problem by automatically scanning all the frequencies
available in the receiver's frequency block and tuning the
receiver to the frequency with the lowest RF interference,
significantly reducing setup time.

Digital Hybrid WirelessTM is a patent-pending, revolutionary

new design that combines digital audio with an analog FM radio
link to provide outstanding audio quality and the extended
operating range of the finest analog wireless systems. The
process eliminates a compandor and its artifacts.

The design overcomes channel noise in a dramatically new
way, digitally encoding the audio in the transmitter and decoding
it in the receiver, yet still sending the encoded information via an
analog FM wireless link. This proprietary algorithm is not a
digital implementation of an analog compandor. Instead, it is a
technique which can be accomplished only in the digital
domain, even though the audio inputs and outputs are analog
signals.

analyze and then latch the phase in the best position during
brief squelch activity.

SmartSquelch™

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 R400A delivers acceptable audio quality from
otherwise unusable signals.

Compatibility Modes

The R400A receiver was 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 unit is also able to operate with
Lectrosonics 200 Series, Lectrosonics 100 Series and
certain non-Lectrosonics transmitters in special compatibility
modes.

SmartNR™

In order to increase the effective dynamic range of the
system, the R400A 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 that 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 not affected.

TECHNICAL DATA

Rio Rancho, NM, USA
www.lectrosonics.com

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 elimi­nated.

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 tones also
eliminates fragile crystals, allowing the receiver to survive
shocks and mishandling much better than older analog­based pilot tone systems.

Specifications

Independent Audio Outputs

The R400A offers both Balanced (XLR) audio output and
Unbalanced (1/4-inch jack) Line Out and Monitor output for
the ultimate in flexibility. Both outputs operate independently
and are each controlled by their own digital attenuator.

Because the Unbalanced Output can drive Low-Z head­phones to a modest level, it can can also be used for system
monitoring.

Operating Frequencies (MHz):

Block 21: 537.600 - 563.100
Block 22: 563.200 - 588.700
Block 23: 588.800 - 607.900

Block 24: 614.400 - 639.900
Block 25: 640.000 - 665.500
Block 26: 665.600 - 691.100
Block 27: 691.200 - 716.700
Block 28: 716.800 - 742.300
Block 29: 742.400 - 767.900
Block 944: 944.100 - 951.900

Frequency Adjustment Range: 25.5 MHz in 100 kHz steps

Channel Separation: 100 kHz

Receiver Type: Triple conversion, superheterodyne, 244 MHz ,

Frequency Stability: ±0.001 %

Front end bandwidth: ±30 MHz @ -3 dB

Sensitivity

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

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

Antenna inputs: Dual BNC female, 50 Ohm impedance

Audio outputs Rear Panel XLR adjustable from -50 dBu to +5 dBu

614.100 - 614.300

10.7 MHz and 300 kHz

(Undetectable after processing)

™

300 kHz

in 1 dB steps. Calibrated into a typical 10 k Ohm
balanced load. Can drive 600 Ohm load.

Rear Panel 1/4 inch jack adjustable from -55 dBu
to +0 dBu in 1 dB steps.

Specifications subject to change without notice

FRONT PANEL CONTROLS AND INDICATORS

Rotary Control Knob: Combined push/rotate switch combination for menu

Pushbutton: Press and hold several seconds for POWER OFF.

LCD Main window: Pilot tone; antenna phase, transmitter battery

Audio output level adjustment: -50 dBu to +5 dBu, XLR and 1/4 inch connectors

Battery level tracking: Receiver and transmitter (9 V battery) in 1/10th volt

Scanning mode: Coarse and fine modes for RF spectrum site

Audio test tone: 1 kHz, -50 dBu to +5 dBu output, < 1% THD

Transmitter battery type selection: 9 V alkaline, 9 V lithium, AA alkaline, AA lithium,

Phase invert: Audio output phase normal or inverted

Smart NR (noise reduction): OFF, NORMAL, FULL modes

Audio Performance:

(These specs apply to 400 Series mode only.)

Frequency Response: 30 Hz to 20 kHz (+/- 1 dB)

THD: 0.2% (typical)

SNR at receiver output (dB):

Input Dynamic Range: 125 dB (with full Tx limiting)

Rear Panel Controls and features: XLR and 1/4-inch phone audio output jack;

Power, Ext DC: Minimum 8 volts to maximum 18 volts DC;

Weight: 13 oz.

Dimensions: 5.50" (14 cm) wide, 1.75" (4.5 cm) high,

selection and system configuration.

Momentary press (if unit is powered up) for return to
previous window

status; audio level, RF level; Battery timer;
Frequency; and Transmitter switch setting

independently adjustable

steps, accuracy +/- 0.2 V.
Transmitter (AA battery), accuracy +/- 0.05 V.
Timer option available.

scanning

TIMER

(avail in 400 Series mode only)

(Overall system frequency response will vary
depending on transmitter used)

SmartNR No Limiting w/Limiting

OFF

NORMAL

FULL

External DC input; BNC antenna connectors.

1.6 W, 200 mA maximum.

6.25" (16 cm) deep

103.5

107.0

108.5

108.0

111.5

113.0

581 Laser Road NE • Rio Rancho, NM 87124 USA • www.lectrosonics.com
[phone] • [phone] • fax [phone] • [e-mail]

November 9, 2005