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HF Receiver EM010

Digital VXI-based HF receiver withbroadband IF output

For a number of years Rohde & Schwarz has been producing digital receiversfor search and monitoring applications. HF Receiver EM010 is the first receiverbased on the VXI standard for use as a plug-in in medium-sized to large radioreconnaissance systems with multiple receiving channels.

Digital receivers with a future

Digital search and monitoring receiv-ers have a long tradition atRohde & Schwarz. Models EK895/EK896 have a proven record as radio-communications and monitoring receiv-ers in professional applications. Thanksto digital signal processing, the receiv-ers are open-ended for new modula-tion modes and transmission methods.The A/D conversion meets the moststringent requirements, while the linear-ity and dynamic range of the detected

signals are retained in full.

Digital HF Receiver EM 010 basedon the VXI standard is a brand-newdevelopment, a unique combinationof linearity, dynamic range and highfunctionality within compact dimen-sions: SOI typ. 95 dBm TOI typ. 40 dBm

Phase noise better than110 dBc/Hz (1 kHz offset)

Sensitivity better than 113 dBmfor SSB (2.75 kHz bandwidth)and 10 dB SINAD

EM010 is designed as a plug-in foruse in extensive radio reconnaissancesystems where multiple channels aremonitored simultaneously (FIG).

The VXI standard (VME bus exten-

sion for instrumentation; VME: versa

modular Eurocard IEEE 1014) allowsextremely flexible combination ofdigital receivers with further signalprocessing components, eg DSP BoardGX400DP from Rohde & Schwarz.

Narrowband or broadband?

Radio reconnaissance is increasinglyconfronted with extremely complexsignal scenarios that make greatdemands on the flexibility of receivingsystems. Given the enormous variety ofsignals encountered, the following ques-tion is more relevant than ever: Howcan I detect emissions accurately andmaintain high signal quality withoutsacrifices in subsequent demodulation

and analysis? In other words, receiverfilters should be as narrowband aspossible and as broadband as neces-sary.

For instance, weak signals travelling ina disturbed environment or near strongfields must be detected and processedin narrow bands. HF Receiver EM010is ideal for such critical applications.

The receivers digital IF filters afford

virtually unlimited adaptability to com-plex signal scenarios. Functions likegain control, noise blanking or squelchare more precise and reproduciblethan ever before thanks to fully digitalsignal processing.

These characteristics make EM010 theideal narrowband receiver for radioscenarios in the shortwave range.

The requirements for the detection of FH

(frequency hopping) and DSSS (direct

Ph

oto43430/2

Fast digital plug-in HF Receiver EM010 for flex-ible integration in complex radio reconnaissancesystems

News from Rohde& Schwarz Number 168 (2000/III) 25

Articles

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signal spread spectrum) are completelydifferent, calling for broadband receiv-ers.

Thanks to its versatile digital technology,EM010 is best suited for this purpose

too. It comes with a 4 MHz broadbandoutput in addition to an AF output anda narrowband IF output. Used togetherwith another VXI module, a broadbandadd-on board with A/D converter andan adequate number of digital down-converters (DDCs), EM010 becomes apowerful broadband, digital multichan-nel receiver. In this case the DDCsserve as digital handoff receivers.

Numerous applications

Fitted with the broadband add-onboard, EM010 covers a variety ofadditional applications: Intermediate storage of broad-

band signals Signal-adapted detection Visualization of broadband spec-

trum versus time Monitoring of broadband fre-

quency occupancy

Implementation of filters for time,level, frequency and direction(in combination with directionfinders)

Statistics for level/frequency ordwell time/frequency and otheruser-defined applications

HF Receiver EM010 with its digitalversatility opens up the way to process-ing new and complex signal transmis-sion methods in future communications

intelligence.Theodor Fokken

Operating modes Fixed frequency Memory scan

Frequency scan Replay (IF/AF) Test

Data output Baseband signal (I and Q) in dig-

ital form, maximum bandwidth20 kHz

IF analog (455 kHz) IF analog (38 kHz to 58 kHz or

40.048 MHz 2 MHz) DAT recorder connector AES/

EBU AF digital AF analog (line 600 and head-

phones)

Demodulation in fixed frequencymode AM FM SSB CW

IF bandwidth is selectable in 70 stepsfrom 52 Hz to 20 kHz.

BFO can be set in 1 Hz steps in thefrequency range from 10 kHz.

Squelch selection between languageand level. The latter can be set withinthe limits from 20 dBV to 100 dBV

in 1 dB steps.

Preamplifier can be switched on andoff.

Gain control either automatic (AGC)or manual (MGC).

Two notch filters can be selected inde-pendently of each other.

Memory scan allows setup of all

relevant parameters per channel: Memory location Frequency Demodulation mode Bandwidth BFO frequency Preamplifier AGC/MGC settings Squelch parameters

In replay mode recorded IF data canbe fed back via data interfaces, eg to

process them with a different band-width or demodulation mode.

The test mode carries out an extensiveselftest of the receiver. This is possibleeither full-length or abbreviated, butthe abbreviated version only signalsgo or nogo.

Condensed data EM010Frequency range 1.5 MHz to 30 MHz (10 kHz to 1.5 MHz

with limited specs)Tuning time