Lectrosonics Inc D4T Manuel D’Utilisation

3

Introduction

The D4 digital 4-channel wireless system was de-

signed as a special purpose system for location pro-

duction in film and television.
A typical application for this system is in television 

production as part of what is commonly called a “bag 

system.” A portable mixer and several wireless mi-

crophone receivers are carried in an over-shoulder 

carrying case. The D4T transmitter is connected to the 

outputs of the mixer to transmit up to four audio chan-

nels to one or more D4R receivers mounted on video 

cameras.
The system is designed for line level analog audio sig-

nals and AES/EBU digital audio signals and can be set 

up as a 2-channel or 4-channel system with options 

that provide:

•  Digital in/Digital out (< 1 mS latency)

•  Digital in/Analog out

•  Analog in/Digital out

•  Analog in/Analog out (2.2 mS latency)

In the 4-channel mode, the D4 system operates on 

one of four 4.2 MHz channels in the 902 to 928 MHz 

band. Each channel carries four separate audio sig-

nals, digitally multiplexed within a common carrier. D4 

systems can be run simultaneously on all four chan-

nels across the 902 to 928 MHz band to provide a total 

of 16 channels.

907.776

912.384

916.992

921.600

902 to 928 MHz Band

A “spreading” technique is used in the design to in-

crease immunity to noise and interference. The sam-

pled audio signals are delivered to the FPGA where 

the spreading algorithm and encoding are applied.
The audio quality is suitable for any professional appli-

cation in film, television and live sound. 48 kHz sam-

pling and 24-bit A-D conversion assure excellent audio 

quality across a 20Hz to 20kHz audio bandwidth with 

only 0.05% distortion.
The LCD interface on the front panels make setup 

simple and straightforward. Power is provided by exter-

nal sources from 6 to 16 VDC.
Rugged machined aluminum housings are finished 

in a Teflon impregnated nickle alloy plating with laser 

etched nomenclature for durability and legibility.

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