User's Manual

Digital Transmitter
Rio Rancho, NM
3
Introduction
The DCHT, DCHT/E01 transmitter is designed to work
with a companion receiver (such as the Lectrosonics
M2R, part of the Duet IEM system) as an audio relay
between an audio production bag or cart and a camera
or other audio device. The 6-pin input jack accepts two
mic or line level analog signals or AES digital signals
from external sources with a variety of adapter cables.
Analog inputs can be linked for the same gain when
used with a stereo source, or operate independently
with individual settings.
This third generation digital design features specially
developed, high efficiency digital circuitry for extended
operating time on two AA batteries. The transmitter can
tune in coarse or fine steps across the UHF television
band from 470.100 to 607.950 MHz (E01 frequency
range is 470.100 to 614.375 MHz), with a selectable
output power of 10, 25 or 50 mW.
Studio quality audio performance is assured by high
quality components in the preamp, wide range input
gain adjustment and DSP-controlled limiting. and
settings are included for any lavaliere microphone,
dynamic microphones and line level inputs. Input gain
is adjustable over a 51 dB range in 1 dB steps to allow
a precise match to the input signal level, to maximize
dynamic range and signal to noise ratio.
A separate switch is provided on the top panel that can
be configured as mute, power or bypass.
The housing is constructed of solid machined aluminum
for lasting ruggedness. The exterior is finished with an
ultra hard, dark electroless nickel finish called ebENi.
Firmware updates are made through a side panel micro
USB port.
Canada ISED Notice
This device operates on a no-protection, no-interference basis. Should the user seek to obtain
protection from other radio services operating in the same TV bands, a radio licence is required.
For further details, consult Innovation, Science and Economic Development Canada’s document
Client Procedures Circular CPC-2-1-28, Voluntary Licensing of Licence-Exempt_Low-Power
Radio Apparatus in the TV bands.
General Technical
Description
DSP-controlled Input Limiter
The transmitter employs a DSP-controlled analog audio
limiter prior to the analog-to-digital converter. The limiter
has a range greater than 30 dB for excellent overload
protection. A dual release envelope makes the limiter
acoustically transparent while maintaining low distor-
tion. It can be thought of as two limiters in series, con-
nected as a fast attack and release limiter followed by
a slow attack and release limiter. 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 in the audio level.
Encryption
When transmitting audio, there are situations where pri-
vacy is essential, such as during professional sporting
events, in court rooms or private meetings. For instanc-
es where your audio transmission needs to be kept
secure, without sacrificing audio quality, Lectrosonics
implements AES256 encryption in our digital wireless
microphone systems. High entropy encryption keys are
first created by the DCHT Transmitter. The key is then
synced with an encryption-capable digital receiver, via
the IR port. The audio will be encrypted and can only
be decoded if both DCHT and receiver have the match-
ing encryption key. If you are trying to transmit an audio
signal and keys do not match, all that will be heard is
silence.