Sennheiser FT-906A20, FT-902S50, FT-906B20, FT-902S15, FT-905A User Manual

...

INSTRUCTION FOR USE

EM 203

CONTENTS

1 TECHNICAL OVERVIEW

1.1 Computer Control

1.2 Diversity

1.3 HIDYN plus® noise reduction system

1.4 Block diagrams

2 POSSIBLE TRANSMITTER/RECEIVER COMBINATIONS

2.1 EM 203 receiver/SK 2012 TV(HiDyn plus®) and SKM 4031 HiDyn plus

2.2 EM 203 receiver/SK 50/250 UHF and SKM 5000 (HiDyn plus®)

2.3 EM 203 receiver/SER 20 transceivers

3 PUTTING THE EM 203 TO WORK

3.1 Mains connection

3.2 Antenna connection

3.3 AF connection

3.4 Start-up procedure/operating indicators

4 AVAILABLE MODULES

4.1 EM 1046 RX RECEIVER MODULE

4.1.1 Adjustment

4.1.2 Receiver frequencies

4.1.3 Squelch

4.1.4 Selection RF signal/deviation/battery condition

4.1.5 Display-text/frequency/battery condition

4.1.6 Entry of brief text

4.1.7 System configurations and specifications

4.1.8 Remote monitoring of transmitter battery

4.1.9 Monitoring of audio signals

4.1.10 Stand-by

4.2 MONITOR

4.2.1 LED indicators

4.2.2 Monitor headphones

5 TECHNICAL DATA

Introduction

The wireless Mikroport multi-channel sound transmission system EM 1046 is a transmitter/receiver system in a modular design. It offers comfortable handling and can be relied on for dependable service.

• 3-channel diversity receiver EM 203 with microprocessor-controlled receiver modules

• Ultimate flexibility in the selection of transmitter and receiver frequencies thanks to easy-to-replace PROMs and EEPROMs.

The present manual shall help you to get acquainted with the EM 203 receiver.

• The chapter "START-UP PROCEDURE" helps you to connect the unit to the mains and to put it to work.

• The chapter "AVAILABLE MODULES" provides you with information on every single module. It explains how to adjust them to satisfy your individual transmission requirements.

The necessary modules for this receiver system are incorporated into a "Mainframe". For programming and servicing, the EM 1046 RX receiver modules can be removed to the front. Output module, input module and mains power supply module, however, are integral parts of the system.

IMPORTANT INFORMATION

Each HF input is supplied with a wideband power distributor 1:3, which intendedly does not affect the adjustment possibilities of the EM 1046 RX receiver modules. In order to achieve sufficient sensitivity and protection against subscriber's extention stations, an antenna with booster and pre-selection is required. In general, Sennheiser's AB 1036 TV antenna booster is used.

Refer programming of the EEPROMs in the receiver modules to qualified service personnel or Sennheiser's Service Department, 30900 Wedemark, Germany.

Technical overview 1

Computer control 1.1 Diversity 1.2 HiDyn plus® noise reduction 1.3 Block diagrams 1.4

Computer control

1.1

Every single EM 1046 RX receiver module has an in-built microprocessor for the RF section, the operating elements and all indicators. It serves to control the following components or parameters:

• phase locked loop (PLL) synthesizer

• function of keys

• 8 digit LED display

• two LED bargraph displays

• true diversity

• monitoring

• squelch threshold

• description fields

• stand-by

• storage of all receiver parameters (e. g. receiver frequencies) in a permanent memory

During diversity operations, the microprocessor controls every one of the two receiver chains that are combined on one module.

The receiver parameters and the selectable frequencies can easily be changed with the help of a conventional computer system as every receiver module incorporates an additional service interface. Changes are only possible within the admissible RF bandwidth.

The software can easily be adapted to your individual requirements and updated at any time by Sennheiser’s Service Department. Our servicemen simply replace the PROM in the receiver modules.

Diversity

1.2

Receiver 1

Control signal

Automatic electronic switching

of audible frequency signal

Steuersignal

Control signal

Receiver 2

Every EM 1046 RX receiver module operates on true diversity. An antenna splitter, integrated into the chassis, serves to route the antenna signals from both antennas to the three receiver modules.

The receiving antenna not only receives direct electromagnetic waves, but also reflections from walls, windows, ceilings and other installations, which results in the cancellation of these waves, so-called „field strength gaps“. Repositioning the receiving antenna is a possible remedy, provided the transmitter remains in its original position. However, as most transmitters are used for portable applications, the „field strength gaps“ then occur in other positions. The effects of field strength variations can only be eliminated through the use of true diversity techniques.

Sennheiser’s specially developed diversity system is based on two receivers operating on the same frequency and two separate antennas. A comparator ensures that the receiver with the strongest RF signal is automatically and noiselessly switched to the AF output. Diversity operations can compensate for considerable variations in field strength, thus providing an enormous gain in transmission reliability.

Nota bene: Every single EM 1046 RX receiver module incorporates two receivers for diversity operation.

HiDyn plus

DYNAMICS OF THE AUDIO SIGNAL

IN THE RF-SIGNAL (MAX 60 DB)

1.3

DYNAMICS OF THE AF INPUT SIGNAL

COMPRESSION AT

THE TRANSMITTER

HIDYN plus

SYSTEM NOISE PLUS MODULATION/DEMODULATION

NOISE IN THE TRANSMITTER PATH

EXPANSION AT THE RECEIVER

HIDYN plus

»HIDYN plus®« NOISE REDUCTION SYSTEM

The »HIDYN plus®« noise reduction system serves to reduce the effects of RF interference fields. It increases the signal-to-noise ratio and gets close to about 110 dB for peak modulation.

DYNAMICS OF THE AF OUTPUT SIGNAL

»HIDYN plus®« is a wideband compander system. It is a combination of a compressor at the transmitter (ratio 2:1) and an expander at the receiver, the compressor reducing the volume of the signal and the expander restoring it. The optimized dynamic range and the control amplifier in the transmitter effectively reduce modulation problems.

»HIDYN plus®« has been expecially developed by Sennheiser for studio and stage applications.

Its features:

• extemely low degree of noise modulation

• level compensation

• excellent dynamic range due to the control amplifier

Block diagram EM 203

1.4

Possible transmitter/ 2 receiver combinations

EM 203 receiver/ 2.1 SK 2012 TV (HiDyn plus®) and SKM 4031 TV-HiDyn plus Transmitters

EM 203 receiver/ 2.2 SK 50/250 UHF and SKM 5000 (HiDyn plus Transmitters

EM 203 RECEIVER/ 2.3 SER 20 TRANSCEIVER

)

EM 203 receiver/ SK 2012 TV (HiDyn plus®) and SKM 4031 TV-HiDyn plus

2.1

NOTA BENE

SK 2012 body-pack transmitters can be retrofitted (change from HIDYN® to HIDYN plus®) to make them suitable for use with EM 1046 receivers.

To this purpose please send the transmitters to be retrofitted to Sennheiser's Service Department, 30900 Wedemark.

Attention: After the transmitters have been retrofitted, they are no longer compatible with HIDYN

MKE 2-2 R

SK 2012 TV (HiDyn plus®)

MKE 10-2 R

MKE 102-2 R

NOTA BENE

SKM 4031 TV transmitter microphones can be used in conjunction with EM 203 systems if they incorporate a HIDYN plus® compander. This is the case with SKM 4031 HIDYN plus

condenser microphones.

Models incorporating a compander can be retrofitted. To this purpose please send the microphones to Sennheiser's Service Department, 30900 Wedemark, Germany.

Attention: After the transmitters have been retrofitted, they are no longer compatible with HIDYN

SKM 4031 TV-HiDyn plus

2 GZA 1036 TV

450 - 800 MHz

2 GZA 1036-9 140 -960 MHz

AB 1036 TV

EM 203 receiver

EM 1046/ SK 50 UHF / SK 250 UHF and SKM 5000

2.2

SKM 5000

MKE 2-4

MKE 10-4

SK 50 UHF / SK 250 UHF

2 GZA 1036 TV

450 - 800 MHz

2 GZA 1036-9 140 -960 MHz

MKE 102-4

EM 203 receiver

AB 1036 TV

EM 203 receiver/ 2.3 SER 20 transceiver

Refer retrofitting to Sennheiser distributors or Sennheiser's Service Department, 30900 Wedemark, Germany.

At the time that the present brochure went to print the retrofit kit for the SER 20 transceiver was already under development. Please contact your Sennheiser distributor for further information on the exact date of delivery.

Another possibility: If you don't need the advantages of HIDYN

2 GZA 1036 TV

450 - 800 MHz

2 GZA 1036-9 140 -960 MHz

AB 1036 TV

SER 20 transceiver with HiDyn plus

EM 203 receiver

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