Lectrosonics UT400 - Manual (Page 4)

UT
General Technical Description
Introduction
The UT Digital Hybrid Wireless™ handheld transmitter
uses state-of-the-art wireless technology with a high-
powered 100mW RF output and a unique microphone
capsule arrangement. The VariMic™ preamp allows the
user to custom-tailor the microphone’s response to suit
the application.
Three capsules are available for this transmitter: a cardi­
oid condenser, an omni condenser and a super-cardioid
condenser. Each capsule assembly comes complete
with the VariMic™ preamp.
In addition to providing peerless audio quality in native
400 Series mode, the Digital Hybrid Wireless™ tech­
nology in the UT transmitter allows compatibility with a
wide range of receiver types, including Lectrosonics 100
and 200 series and IFB. The UT is also compatible with
receivers from other manufacturers. Contact Lectroson­
ics for details.
Digital Hybrid Technology
All wireless links suffer from channel noise to some
degree and all wireless microphone systems seek to
minimize the impact of that noise on the desired sig­
nal. Conventional analog systems use compandors for
enhanced dynamic range, at the cost of subtle artifacts
(known as “pumping” and “breathing”). Wholly digital
systems defeat the noise by sending the audio informa­
tion in digital form, at the cost of some combination of
power, bandwidth and resistance to interference.
UT Block Diagram
The Lectrosonics Digital Hybrid Wireless™ system
(hereafter called Digital Hybrid) 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 but a
technique which can be accomplished only in the digital
domain, even though the inputs and outputs are analog
signals.
Because it uses an analog FM link, the Digital Hybrid
enjoys all the benefits of conventional FM wireless
systems, such as excellent range, efficient use of RF
spectrum, and long battery life. However, unlike con­
ventional FM systems, the Digital Hybrid has done away
with the analog compandor and its artifacts.
Digital Signal Processor
The DSP encodes the digitized audio from the A-D con­
verter and adds an ultrasonic pilot tone to control the
receiver’s squelch (only in 400 Series, 200 Series and
IFB compatibility modes with the pilot tone enabled –
see Pilot Tone Squelch). It also controls the input limiter
and audio metering.
Microprocessor, PLL and VCO Circuits
An 8-bit microprocessor monitors numerous internal
signals. It also drives the Modulation LEDs, controls the
pilot tone and operates the PLL/VCO circuits.
LECTROSONICS, INC. 4