Lectrosonics WM Specifications

WM

Watertight Transmitter

• Selectableoutputpowertomaximizebatterylifeor
operatingrange

• Machinedaluminum,corrosionresistanthousing

• Waterresistantsealsforuseinwetenvironments

• LCDinterfacewithlockoutoption

• Programmablecompatibilitymodesforusewitha
widevarietyofdifferentreceivers

• ServoBiasinputcircuitrywithselectablevoltage

Designed for wet or dusty environments, the WM trans­mitter features O-ring sealed battery compartments and
input jack, a compression sealed antenna port and gas­ket sealed control panel and back cover. Dual AA batter­ies provide twice the operating time of earlier watertight
transmitter designs. Larger membrane switches and
control panel and a highly visible, backlit LCD enhance
the user interface.

Digital Hybrid Wireless® is a revolutionary new design

that combines digital audio with an analog FM radio link to
provide outstanding audio quality and the exemplary RF
performance of the finest analog wireless systems.

This 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.

The process eliminates compandor artifacts, expanding the
applications to include test and measurement of acoustic
spaces and musical instruments.

TECHNICAL DATA

To meet the demand for both extended operating range
and extended battery life, the transmitter offers select­able output power of 50, 100 and 250 mW. With higher
power output, the operating range is improved at the
expense of battery life. When range is not an issue, the
power can be reduced to extend the battery life.

The transmitter can be controlled by the RM and RM2
remote control units for hands free setup and adjustment
using audible tones delivered into the microphone from a
tiny loudspeaker in the remote control unit. The transmit­ter can be put to sleep to conserve battery power during
setup when it is buried deep inside costuming, then
awakened for normal operation when the production
begins. Other adjustments include frequency, audio level
and control panel lockout.

The DSP-based design works with all Digital Hybrid re­ceivers, and is backward compatible for use with Lectro­sonics 200 and 100 Series and IFB receivers and some
other brands of analog wireless receivers.

The input section features servo bias circuitry with
voltages being selectable from the LCD to match the
requirements of a wide variety of lavaliere microphones.
The bias can also be turned off for use with dynamic
microphones. A line level setting is provided for use with
signal levels up to 5 volts. The low frequency roll-off can
be adjusted from 35 to 150 Hz.

A DSP-controlled analog audio limiter is employed ahead
of the first mic preamp to protect the entire audio chain
from overload. The limiter has a range of more than 30
dB for excellent overload protection and a dual release
envelope that makes the limiter acoustically transparent
while maintaining low distortion.

Rio Rancho, NM, USA
www.lectrosonics.com

Watertight Connections

The input connector is mounted in a recessed open­ing which provides a captive seat for the O-ring on the
microphone connector. This captures the O-ring allowing
it to be tightened firmly.

The antenna is mounted with a compressible strain
relief under a flange that presses the strain relief into a
tapered opening for a watertight connection.

Input Limiter

A DSP-controlled analog audio limiter is employed
before the analog-to-digital converter. The limiter has a
range of more than 30 dB for excellent overload protec­tion. A dual release envelope makes the limiter acousti­cally transparent while maintaining low distortion. The
limiter recovers quickly from brief transients, so that its
action is hidden from the listener, but recovers slowly

from sustained high levels, to keep audio distortion low
and preserve short term dynamic changes.

The bicolor LEDs on the control panel indicate limiter
activity accurately to assist in setting the input gain for
optimal signal to noise ratio and dynamic range.

DSP-Based Pilot Tone & Compatibility

The DSP generated pilot tone eliminates the need for
fragile crystals and allows a different pilot tone frequency
for each of the 256 carrier frequencies in the tuning
range of the wireless system. Individual pilot tones sig­nificantly reduce squelch problems in multichannel sys­tems where a pilot tone signal can appear in the wrong
receiver via intermodulation products.

The DSP also offers compatibility modes to allow back­ward compatibility with all Lectrosonics IFB systems,
100/200 Series systems and analog receivers from
some other manufacturers in addition to its native Digital
Hybrid operating mode.

Output Isolator

The transmitter RF output circuit includes a specialized
RF device called an isolator using a magnetically polar­ized ferrite to allow RF signals to pass through to the
antenna, but block them from coming backward into the
transmitter output section.

The isolator greatly reduces RF intermodulation produced
in the transmitter output stages when multiple units are
used in close proximity (a few feet apart). The isolator also
helps protect the output stage from electrostatic shock
delivered to the antenna. Isolators are common in broad­cast and commercial applications, but because of their
high cost it is unusual to find them in wireless microphone
transmitters.

+5V

5V

Regulator

+6V

Variable 1.8 - 4v

Remote Control

RM Remote Control

The RM gives you remote control of the WM transmitter
using an audible tone delivered to the microphone. Oper­ating parameters on the wireless transmitter can be set by
holding the speaker on the RM close to the microphone
and pressing the pushbutton. A “dweedle” tone will play
from the RM speaker into the microphone and the pa­rameter on the transmitter will be set immediately. Adjust­ments can be made to set:

• Audioinputgain

• Frequency

• LockorUnlockModes

• SleepModeON/OFF

Speaker

The flexible, intuitive interface on the RM makes setting
these parameters quick and easy. The dweedle tones that
control the transmitter are complex and can be detected
in the midst of noise, yet they cannot be mistaken for the
natural sound entering the microphone.

A single RM is capable of controlling a WM transmitter in
any frequency block. Since it can simultaneously control
multiple transmitters, the loudness of the tone is adjust­able to suit different situations. With the volume turned up,
changes can be made at a distance of up to 6 feet from
the microphone. The volume can also be turned down so
only microphones within a few inches of the speaker will
pick up the tone.

The RM eliminates the need to disturb wardrobe or talent
other than to make a quick, hands-free pause to send the
dweedle tone into the microphone. Since the microphone
is always positioned to pick up sound from the talker’s
voice, it is always accessible for setup changes using
the the RM. Even with the microphone concealed under
fabric, the tone will still reach the microphone. A remote
control system using an IR (infrared) signal would require
a line of sight between remote module and transmitter.

Input gain is adjusted by setting the desired value on the
LCD on the RM in the same manner as it is adjusted on
the transmitter. A single pushbutton press and a brief tone
burst then transfers the setting to the transmitter. Fre­quency is adjusted in the same manner, with the options
of setting it directly by hex switch code or adjusting it by
block and frequency in MHz.

SendButton

The RM is supplied with a quick-release lanyard

The Lock and Unlock functions on the transmitters are
used to safeguard the settings and prevent accidental
adjustment. When Lock Mode is enabled, the switches
on the transmitter control panel will not operate. The RM
can be used to unlock or lock the transmitter controls
with a brief dweedle tone. The only way to unlock the
controls with the transmitter itself is to remove the bat­tery.

The Sleep and Unsleep functions are used to extend
battery life during idle conditions. This is very use­ful when lengthy preparations are necessary or with
extensive costuming. The transmitter and microphone
can be placed and concealed early in the process and
the transmitter then put to sleep with the RM, which
reduces power consumption by a factor of 5. When
the production is ready to start, a quick dweedle tone
wakes up the transmitter and operation resumes.

The life of the single AA battery that powers the RM
itself is extremely long. A lithium AA battery may run
the unit for several years depending upon how often the
unit is used, how loud the tone is played and storage
conditions.

The machined aluminum housing and corrosion-resis­tant finish protect against damage from rough handling
and moisture. A membrane switch panel helps protect
the LCD and internal circuits from moisture and dust.

RM2 Remote Control

The RM2 is a lower cost alternative remote control with
a simple push button interface. Adjustments can be
made to:

• TurnthetransmitterSleep

Mode On and Off

• LockorUnlocktransmitter

controls

• AdjusttransmitterAudio

Input Gain

Specifications

z1

Operating frequencies:

Block 470 470.100 - 495.600
Block 19 486.400 - 511.900
Block 20 512.000 - 537.500
Block 21 537.600 - 563.100
Block 22 563.200 - 588.700

Channel Spacing: 100 kHz
Frequency selection: Control panel mounted membrane switches
RF Power output: Switchable; 50, 100 or 250 mW
Compatibility Modes (6) Digital Hybrid Wireless

200 Series, 100 Series, Mode 3, Mode 6, IFB
Pilot tone: 25 to 32 kHz; 5 kHz deviation

(in 400 Series Hybrid Mode)

Frequency stability: ± 0.002%
Deviation: ± 75 kHz max. (in 400 Series Mode)
Spurious radiation: 60 dB below carrier
Equivalent input noise: –125 dBV, A-weighted
Input level:

Dynamic mic: 0.5 mV to 50 mV before limiting.
Greater than 1 V with limiting.
Electret lavaliere mic: 1.7 uA to 170 uA before limiting.
Greater than 5000 uA (5 mA) with limiting.
Line level input: 17 mV to 1.7 V before limiting.
Greater than 5 V with limiting.

Input impedance:
Dynamic mic: 300 Ohms
Electret lavaliere: Input is virtual ground with servo adjusted
constant current bias
Line level: > 2.7 k Ohms

Input limiter: Soft limiter, 30 dB range
Bias voltages: Selectable; 2V, 4V and Off
Gain control range: 44 dB; panel mounted membrane switches
Modulation indicators: Dual bicolor LEDs indicate modulation of

–20, -10, 0, +10 dB referenced to full modulation
Controls: Control panel with LCD and four membrane

switches

Block 23 588.800 - 607.900

614.100 - 614.300
Block 24 614.400 - 639.900
Block 25 640.000 - 665.500
Block 26 665.600 - 691.100

®

(400 Series),

AA battery compartments are O-ring sealed

Low frequency roll-off: Adjustable from 35 to 150 Hz

Audio Frequency Response: 35 Hz to 20 kHz, +/-1 dB (The low frequency

roll-off is adjustable - see graph above)

Signal to Noise Ratio (dB):
(overall system, 400 Series mode)

(Note: the dual envelope “soft”
limiter provides exceptionally
good handling of transients
using variable attack and release
time constants. The gradual onset of limiting in the design begins below full modulation,
which reduces the measured figure for SNR without limiting by 4.5 dB)

Total Harmonic Distortion: 0.2% typical (400 Series mode)
Audio Input Jack: 2.5 mm locking micro; threaded for stainless

sleeve on WP connector

Antenna: Flexible, unbreakable steel cable.
Batteries: 1.5 Volt AA lithium

BatteryLife: Lithium

50 mW (2 AA): 14.5 hrs

100 mW (2 AA): 14 hrs

250 mW (2 AA): 7.5 hrs

Weight: 5.33 oz.. (151 grams) with lithium batteries
Housing Dimensions: 2.98 x 2.55 x 0.77 inches

75.7 x 64.8 x 19.6 mm
(including battery caps)

Emission Designator: 180KF3E

+6

+3

0dB

Mic in 35 Hz

-3

Roll-off

Line in

-6

-9

-12

Mic in 150 Hz

Roll-off

30

100

1kH

20k

0k

SmartNR No Limiting w/Limiting
OFF 103.5 108.0
NORMAL 107.0 111.5
FULL 108.5 113.0

Therecessinthebatterycompartment

trapstheO-ringforatightseal.

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

Specifications subject to change without notice.

03 July 2012