Lectrosonics HMa Data Sheet

HMa

UHF Plug-on Transmitter

This unique plug-on transmitter design will ideally match
any microphone or line level source via a standard XLR
connector. Phantom power is selectable at 5, 15 and 48
volts, or can be turned off for use with dynamic micro­phones and line level signal sources.

The design includes a wide tuning range of up to 76
MHz, with tuning steps in increments of 100 kHz or 25
kHz for up to 3072 frequencies. The tuning range covers
three standard 25.6 MHz Lectrosonics frequency bands.
Each of the standard bands includes 256 different pilot
tone frequencies for compatibility with all Digital Hybrid
Wireless receivers.

DSP compatibility modes are also included to work with
legacy Lectrosonics analog wireless microphone receiv­ers and IFB receivers, as well as some receivers from
other manufacturers.

The transmitter is powered by two AA batteries, with
status indicated by a multi-color LED. A USB port is pro­vided for firmware updates. An IR (infrared) port is also
included to simplify setup with IR enabled receivers.

TECHNICAL DATA

• Accepts microphone or line level signals

• Selectable 5, 15, 48 volt phantom power

• 76 MHz tuning range in 100 kHz or 25 kHz
steps for up to 3072 frequencies

• Selectable 50/100 mW output power

• Adjustable low frequency roll-off

• Powered by two AA batteries

• USB port for firmware updates

• IR (infrared) port for fast setup

• Remote controlled “dweedle” tones (audio
tone set-up control)

• Solid machined aluminum housing

The input amplifier uses an ultra low noise op-amp for
quiet operation. It is gain controlled with a wide range
dual envelope limiter, providing over 30 dB of headroom
above full modulation. A 24-bit A-D converter digitizes
the audio, then filters supersonic noise above 21 kHz.
The resulting signal is encoded with a proprietary algo­rithm to produce an analog data signal for RF transmis­sion. The underlying RF link is an optimized FM system
with +/-75 kHz wide deviation for a high signal to noise
ratio.

The audio performance of the overall hybrid system is de­picted in the graph below. Distortion in the overall system
is extremely low over the entire audio bandwidth.

Digital Hybrid Wireless® is a revolutionary 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.

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.

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

*US Patent 7,225,135

The antenna is formed between the machined aluminum
housing of the transmitter and the attached microphone
or cable. It functions as a dipole radiator when attached
to a hand-held microphone and somewhat like a ground
plane antenna when connected with a cable or plugged
directly into a mixer. The conical shaped collar on the
input coupler is made of DuPontTM Delrin® to improve the
ERP of the antenna in the uppermost frequency bands.

Rio Rancho, NM, USA
www.lectrosonics.com

Specifications

Operating Frequencies:
Band A1: 470.100 - 537.575
Band B1: 537.600 - 614.375
Band C1: 614.400 - 691.175

Frequency Selection Steps: Selectable; 100 kHz or 25 kHz
RF Power output: Selectable 50/100 mW
Pilot tone: 25 to 32 kHz; 5 kHz deviation

(in the Digital Hybrid mode)
Frequency stability: ± 0.002%
Deviation: ± 75 kHz (max in Digital Hybrid mode)
Spurious radiation: 60 dB below carrier
Equivalent input noise: –125 dBV (A-weighted)
Input level: Nominal 2 mV to 300 mV, before limiting.

Greater than 1V maximum, with limiting.
Input impedance: 300 Ohms
Input limiter: Dual envelope “soft” limiter; greater than 30

dB range
Gain control range: 55 dB; panel mounted membrane switches
Modulation indicators: Dual bi-color LEDs indicate modulation of

-20, -10, 0, +10 dB referenced to full
modulation

Audio Performance (overall system):
Frequency Response: 35 Hz to 20 kHz (+/-1dB);

Low frequency Roll-off: Adjustable for -3dB @30, 50, 70 Hz)
THD: 0.2% (typ. 100 Hz to 20 kHz - see graph)
SNR at receiver output:
Note: The dual envelope “soft”

limiter provides exceptionally
good handling of transients using
variable attack and release time
constants.
Once activated, the limiter compresses 30+ dB of transmitter input range into

4.5 dB of receiver output range, thus reducing the measured figure for SNR
without limiting by 4.5 dB.

Input Dynamic Range: 125 dB (with full Tx limiting)
Controls & Indicators: • Power/Phantom “ON-OFF”

• Phantom voltage selector

• Audio input gain

• LCD w/membrane switches

• LED audio level indicators

SmartNR no limiting w/limiting

OFF 103.5 108.0

NORMAL 107.0 111.5

FULL 108.5 113.0

The battery compartment door is hinged to the housing
and remains attached to the transmitter when opened.
It securely latches in place and applies pressure to the
batteries when closed. The two AA batteries are con­nected in series through a conductive plate on the door.

Setup and adjustments are made with the control panel
membrane switches and LCD. The transmitter can be
powered up without the transmitter output enabled
to allow frequency
adjustments without
causing interference to
other wireless systems
nearby. The switches
can also be bypassed
to prevent accidental
changes.

Dual color LEDs indicate audio input level and the power
LED changes color under low battery conditions.

Audio Input Jack: Standard 3-pin XLR (female)
Phantom Power: 5V @ 18 mA max., 15V @ 15 mA max.

and 48 V @ 4 mA max., plus “OFF”
USB port: Used for firmware updates
IR (infrafed) port: For quick setup by transferring settings from

an IR enabled receiver
Antenna: Housing and attached microphone form

the antenna
Battery: Two 1.5 Volt AA alkaline
Battery Life (Duracell Quantum):
AA alkaline; No Phantom Power: 5h 0m*

AA alkaline; 48V Phantom Power: 3h 30m**
*Tested with a dynamic microphone

**Tested with a Sanken CS1 for a phantom-powered microphone
Weight: 7.5 ozs. (211 grams) w/ AA batteries
Dimensions: 4.25x1.62x1.38 inches
Emission Designator: 180KF3E

IR (infrared) port

USB port

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

02 May 2016