General Technical Description - Lectrosonics DHu Instruction Manual

General Technical Description

Introduction
The DHu handheld transmitter delivers superb audio
quality and extended operating range in a pure digital
architecture. Interchangeable microphone capsules
expand the versatility to suit a wide variety of applica-
tions and personal preferences. The superb audio per-
formance and highly reliable RF transmission makes it
ideally suited for high end stage and studio production.
Frequency Selection
The transmitter tunes continuously from 470.100 to
607.975 MHz in 25 kHz steps, making it easy to find
clear operating frequencies. Operating frequency is
normally selected using a receiver or analyzer to as-
sess signals in the local environment to avoid interfer-
ence. Once an interference-free frequency is identified,
the transmitter frequency is set to match the receiver.
Input Gain Range and Limiter
45 dB range of input gain adjustment allows gain
settings to accurately match the user's voice and the
varying sensitivity of different microphone capsules. A
DSP-controlled analog audio limiter is employed be-
fore the A-D converter. The limiter has a range of more
than 30 dB for excellent overload protection. A dual re-
lease envelope makes the limiter acoustically transpar-
ent while maintaining low distortion. It can be thought
of as two limiters in series, a fast attack and release
limiter followed by a slow attack and release limiter.
The limiter recovers quickly from brief transients, with
no audible side effects, and also recovers slowly from
sustained high levels to keep audio distortion low while
preserving short term dynamics.
Long Battery Life
Switching power supplies throughout the design al-
low over 5 hours of operation using two alkaline AA
batteries. The battery compartment and contacts are
designed to prevent "rattle" as the unit is handled.
Rio Rancho, NM
Digital Hand Held Transmitter
Menu-Driven Control
A high-resolution LCD and control panel with mem-
brane switches provide access to the menu-driven
setup. Transmitter RF power, low frequency rolloff,
frequency selection, backlight timeout settings and
programmable switch functions are easily accessed.
Antenna
A newly designed helical antenna allows the transmit-
ter to be held in any position, since the user's hands
have little or no effect on the RF output power.
Microphone Capsules
The transmitter is available from Lectrosonics with the
HHC cardioid condenser capsule. Capsules from sev-
eral other manufacturers with a 1.25" x 28 thread pitch
and three contact rings are also available for use with
the transmitter. Condenser or dynamic microphone
heads can be used with the transmitter, depending on
the user's preference or the application.
Side Button Functions
A programmable switch on the side of the housing can
be configured as a mute/cough switch, a power switch,
or be disabled.
USB Port for Firmware Updates
Firmware updates are enabled by simply downloading
a file and utility program from the Lectrosonics web
site, connecting the transmitter to a computer via the
USB port and running the program.
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