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4-channel Digital Wireless System

Rio Rancho, NM, USA

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

Center frequencies of the RF channels

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.

Table of Contents

Introduction .............................................................................3

General Technical Description ..............................................4

D4T Transmitter .....................................................................4

D4R Receiver ........................................................................5

Front and Rear Panels ............................................................6

Transmitter Input Modes ........................................................7

Receiver Output Modes .........................................................7

Mixed Modes ...........................................................................7

Navigating the LCD ................................................................7

System Setup Steps ...............................................................8

System Setup ..........................................................................8

D4T Transmitter Audio Level Setup ......................................9

D4R Receiver Audio Level Setup ..........................................9

Antenna Placement and Orientation ...................................10

Frequency Selection ............................................................10

Replacement Parts and Accessories ..................................11

Specifications .......................................................................12

Service and Repair ...............................................................14

Returning Units for Repair ..................................................14

Содержание D4

Страница 1: ...D4 Digital Wireless System INSTRUCTION MANUAL Rio Rancho NM USA www lectrosonics com Fill in for your records Serial Number Purchase Date ...

Страница 2: ...D4T D4R LECTROSONICS INC 2 ...

Страница 3: ... 928 MHz band to provide a total of 16 channels 907 776 912 384 916 992 921 600 902 to 928 MHz Band Center frequencies of the RF channels 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 catio...

Страница 4: ... hum and noise Analog input signals are sampled at 48kHz and con verted to 24 bit digital audio and fed into the FPGA for further processing The FPGA applies a spreading algorithm to expand the bandwidth of each channel to 4 2 MHz to improve immunity to interference and noise The baseband signal is then delivered to the D A to generate the I and Q signals for final output The modulated signal is f...

Страница 5: ...he level of the incoming RF signal to increase the dynamic range capabilities of the receiver From the IQ demodulator through the filters amplifier and baseband ADC the signal path and processing is the reverse of that in the transmitter Decoding in the FPGA regenerates the original digital and analog audio signals and delivers them to the output stages The FPGA also delivers a signal to a DAC and...

Страница 6: ...ype D4T Transmitter FUNC BACK OFF ON 1 2 3 4 DIGITAL 4 CHANNEL TRANSMITTER Channel Select 1 4 Menu Item Parameter Select Return to Previous Menu Press to Enter Setup Menus Audio Level USB AES 3 4 1 2 3 4 9 16 VDC 500 mA AES 1 2 D4T 4 CHANNEL DIGITAL TRANSMITTER The units are powered with an external source of 9 to 16 VDC with power consumption of 500 mA for the transmitter and 250 mA for the recei...

Страница 7: ...NOT USED Mixed Modes The selected AES3 modes on the transmitter and re ceiver do not have to be identical For example analog signals can be fed into the transmitter from a mixer or wireless mic receivers transmitted to the D4 receiver which can be configured for four digital outputs to feed a digital recorder The sampling rate of the audio at the receiver digital outputs will always be at 48 kHz r...

Страница 8: ... 7 Walk test the system to check for adequate op erating range If dropouts occur within the range needed select a different operating frequency System Setup Tuning Menu Use UP DOWN arrows to select menu item and press FUNC to enter setup Use UP DOWN arrows to select channel then press FUNC to return to menu 2 4 Channel Modes Use UP DOWN arrows to select menu item and press FUNC to enter setup Use ...

Страница 9: ... section Attenuation up to 20 dB can be applied to the input signal to reduce very high level signals to the optimal range for the transmitter D4R Receiver Audio Level Setup Press FUNC and then select the menu item Audio Lev and press FUNC again The setup screen for audio level will vary slightly depending upon which AES3 mode has been selected If the 2 channel mode has been selected channels 3 an...

Страница 10: ...ation With multiple systems oper ating in the same location select a different frequency for each system Walk test each system through the area where it will be operating and listen for dropouts while observing the RF level indicator on the receiver LCD It is best to have all equipment in the location turned on to check for interference and short operating range If the RF level on the receiver LCD...

Страница 11: ...0320 universal socket on hous ing 100 240 VAC 50 60 Hz 1 6 A max input 13 8 VDC 2 8A 40 W max output Specify the AC power cord needed for your country or application Power Input Plug and Cables Shogyo MP121CR locking plug no cable Lectrosonics 21425 straight non locking plug with 6 ft cable Lectrosonics 21472 right angle non locking plug with 6 ft cable ...

Страница 12: ...Digital In Digital Out Less than 1 mS Analog In Analog Out 2 2 mS Selectable Audio Channels 4 digital 2 digital 2 analog 4 analog Audio Performance overall system Frequency Response 20 Hz 20 kHz THD 0 05 D4T Transmitter Power output 200 mW spreading algorithm across 4 2 MHz bandwidth Power requirements 9 16 VDC Power consumption 500 mA Dimensions 4 x 4 x 1 5 inches Weight D4R Receiver D4R Receiver...

Страница 13: ...mits for a Class B digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a residential installation The equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no gu...

Страница 14: ...pairs Returning Units for Repair For timely service please follow the steps below A DO NOT return equipment to the factory for repair without first contacting us by email or by phone We need to know the nature of the problem the model number and the serial number of the equipment We also need a phone number where you can be reached 8 A M to 4 P M U S Mountain Standard Time B After receiving your r...

Страница 15: ......

Страница 16: ...trosonics Inc will pay for the cost of returning your equipment to you This warranty applies only to items returned to Lectrosonics Inc or an authorized dealer shipping costs prepaid within one year from the date of purchase This Limited Warranty is governed by the laws of the State of New Mexico It states the entire liablility of Lectrosonics Inc and the entire remedy of the purchaser for any bre...

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