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WJ-8711A

Gain Control Modes .............................................................. Manual, AGC Fast, Medium, Slow

AGC Range ....................................................................... 100 dB, min
AGC Threshold .................................................................. Approximately -108 dBm (0.9 mV) in 16-kHz BW

Approximately -125 dBm (0.12 mV) in 300-Hz BW
(Threshold matched with IFBW, typically 10 dB above
noise floor)

AGC Attack Time ................................................................ 5 msec, typical
AGC Decay Time ............................................................... Fast:

10 to 100 msec, variable

Medium:

100 msec to 1 second, variable

Slow:

1 to 5 seconds, variable

Selectable Front End Gain/Attenuation

Preamplifier Gain ................................................................ 10 dB (+2 dB)
Attenuation ......................................................................... 15 dB (+2 dB)

BFO

Tuning Range .................................................................... +8000 Hz
Tuning Resolution .............................................................. 10 Hz

First Image Rejection ............................................................ 90 dB, min
IF Rejection ........................................................................... 85 dB, min (>90 dB, typical)
LO Phase Noise .................................................................... -110 dBc at 1-kHz offset, typical
Reciprocal Mixing ................................................................. With a desired signal of 25 mV in the 3.2-kHz IFBW, the

desired signal-to-noise ratio (SNR) is >20 dB, when an
undesired signal 70-dB higher in amplitude and 35-kHz
removed in frequency is present.

Cross Modulation ................................................................. With a desired signal of 10 mV, an undesired signal 86-dB

higher, 30% AM modulated produces <10% cross modulation
for frequency separation of >50 kHz in the 1-kHz IFBW.

Internal Spurious .................................................................. <-114 dBm referred to the RF input
Blocking ................................................................................ An unwanted signal 1 mV separated 20 kHz from a desired

signal of 1 mV will not cause the IF output to fall by more than
3 dB.

Line Audio Outputs

Number of Outputs ............................................................. 2 center-tapped, balanced outputs

ISB mode, USB & LSB on separate outputs
All other modes, audio signal common to both outputs

Output Level ...................................................................... 0 dBm, nominal into 600-ohm load
Connector Type .................................................................. Screw terminals

Speaker Output

Number of Outputs ............................................................. One output. For ISB mode, USB & LSB can be selected

individually or combined. (Internal speaker optional).

Bandwidth .......................................................................... 100 Hz to 13 kHz
Output Level ...................................................................... Adjustable up to 1 W into 8-ohm load
Total Harmonic Distortion ................................................... <3% at 1 W
Connector Type .................................................................. Screw terminals

Headphone Output

Number of Outputs ............................................................. 2, unbalanced

ISB mode: 1 output contains USB (left channel), 1 output
contains LSB (right channel)
All other modes, audio signal common to both outputs

Output Level ...................................................................... Adjustable up to 10 mW into 600-ohm load
Connector Type .................................................................. Standard 0.25-in (0.63 cm) stereo jack

Remote Control ..................................................................... RS-232 or CSMA; selectable by internal switch or front panel

entry

RS-232 .............................................................................. Full duplex, 3-wire serial interface; rear-panel 25-pin female

D-shell connector

Baud Rates (Both Interfaces) .............................................. 75, 150, 300, 600, 1200, 2400, 4800 & 9600; selectable by

internal switches or front panel entry

Summary of Contents for WJ-8711A

Page 1: ...om 0 5 to 20 seconds or infinite In channel scan mode 100 programmablememorychannelsareavailable Sectorsof memorycanbespecifiedforindividualchannelscans Digital HF Receiver WJ 8711A Features Frequency...

Page 2: ...e exception of the front panel mountedheadphonejack Theantennaand externalreferenceinputs aswellasthesignalmonitor andpredetectedIFoutputs areavailableonBNC connectors Speakeranddual balancedlineaudio...

Page 3: ...0 20 40 60 80 10 0 110 1 2 0 GA I T HE RS B UR G M D U S A REMOTE CONTROL BY RS 232 OR CSMA CD DEDICATED CONTROLS FOR SCANNING AND MEMORY FUNCTIONS ILLUMINATED SIGNAL STRENGTH METER CALIBRATED IN dBm...

Page 4: ...maninternal10 MHz oscillator that can be locked to an external reference input of 1 2 5 or 10 MHz The WJ 8711A auto maticallysensesandswitchestotheexternalrefer enceuponapplicationofsignal Allcritical...

Page 5: ...tainidenticalaudio signals Thesetwoaudiopathsareprocessedto providea2 channelheadphoneoutput twobalanced 600 ohmlineaudiooutputsandan8 ohmspeaker outputcontainingoneorbothaudiochannelsinISB mode After...

Page 6: ...preamplifier engaged Detection Modes AM SAM FM CW USB LSB ISB consult factory for additional demodulation modes Minimum IFBW S N N Without Preamp Modulation kHz dB Min dBm mV AM 50 mod at 400 Hz 6 0 1...

Page 7: ...14 dBm referred to the RF input Blocking An unwanted signal 1 mV separated 20 kHz from a desired signal of 1 mV will not cause the IF output to fall by more than 3 dB Line Audio Outputs Number of Outp...

Page 8: ...andom vibration 1 04Gs non operating 2 hours B Ground mobile wheeled or tracked vehicle Category 8 Random vibration 6 0Gs operating 15 minutes C Marine shipboard vessel not specified Category 9 Random...

Page 9: ...button functions become especially useful when the WJ 8711A 3 acts as an RF front end for certain DF applications Technical Update WATKINS JOHNSON December 1996 Digital HF Receiver WJ 8711A Specifica...

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