MFJ MFJ-752D Скачать руководство пользователя страница 2

 

MFJ-752D SIGNAL ENHANCER II 

 

INTRODUCTION 

 

 

The  improved  MFJ-752D  SIGNAL  ENHANCER  II  is  comprised  of  two  tunable 

audio  filtering  systems  designed  to  clarity  and  remove  interfering  signals  from  both 
voice (SSB or AM) and code (CW or RTTY) signals.  This is accomplished by a primary 
filter  which  is  a  two-section,  four-pole  variable  filter  which  has  PEAK,  NOTCH,  LOW 
PASS, and HIGH PASS functions, and by an auxiliary filter which is a single section two 
pole  PEAK  or  NOTCH  filter.    These  two  independent  filters  allow  you  to  remove 
interference while enhancing the desired signal. 
 

INSTALLATION 

 

1.

  Connect any 9-18V DC supply to the power jack on the back of the MFJ-752D.  The 

adapter must have a 2.1 mm coaxial plug with the center pin position and the sleeve 
ground.    An  optional  AC  adapter,  MFJ-1312B,    9-18VDC  adapter  is  available  from 
MFJ.  A 12 VDC, 300mA supply is required to obtain the full two watts audio output. 

 

2.

  Using  the  proper  connector,  connect  a  shielded  cable  from  the  external  speaker  or 

headphone jack of the transceiver or receiver to the MFJ-752D.  Use an RCA phono 
plug  to  connect  to  the  filter  input.    There  are  two  inputs  on  the  MFJ-752D  allowing 
connection  to  two  receivers  for  greater  convenience.    The  input  is  selected  by  the 
push button switch on the back of the MFJ-752D. 

 

3.

  Connect a speaker to the filter using shielded wire with a RCA phono plug at the filter 

speaker output.  For best results, use a 4 to 16 ohm speaker. 

 

4.

   Headphone  operation  is  accomplished  by  plugging  headphones  into  the  phone  jack 

on the back of the MFJ-752D.  A mono plug or a stereo plug will work for headphone 
operation.  Plugging in headphones will not mute the speaker jack. 

 
 

FRONT PANEL CONTROLS 

 

POWER SWITCH:  

Selects  power  OFF,  power  ON,  SSB  Noise  Limiter  and  CW  Noise 
Limiter.    The  filter  is  bypassed  on  the  OFF  position.    NOTE:  The 
noise limiter in not ON when the power switch is in the ON position. 

 
PRIMARY FILTER: 

Function Selector:  Selects  PEAK,  NOTCH,  LOW  PASS  (LP),  or  HIGH  PASS  (HP)  in 

the primary filter. 

Selectivity Control:  Adjusts the bandwidth of the primary filter from 40 Hz to almost flat.  
Frequency Control:  Adjusts  the  center  frequency  of  the  peak,  notch  and  the  cutoff 

frequency  of  the  LOW  PASS  and  HIGH  PASS  circuits 
approximately 300 Hz to 3000 Hz. 

Содержание MFJ-752D

Страница 1: ...UAL CAUTION Read All Instruction Before Operating Equipment MFJ ENTERPRISES INC P O BOX 494 MISSISSIPPI STATE MS 39762 USA 925 0037D 752D REV 1 COPYRIGHT 2010 MFJ ENTERPRISES INC MFJ SIGNAL ENHANCER II Model MFJ 752D ...

Страница 2: ...ceiver or receiver to the MFJ 752D Use an RCA phono plug to connect to the filter input There are two inputs on the MFJ 752D allowing connection to two receivers for greater convenience The input is selected by the push button switch on the back of the MFJ 752D 3 Connect a speaker to the filter using shielded wire with a RCA phono plug at the filter speaker output For best results use a 4 to 16 oh...

Страница 3: ...he NOTCH filter is approximately 70 dB Notch frequency is adjustable from approximately 300 Hz to 3000 Hz The primary notch filter can be set to the NOTCH mode by setting the Function Selector to NOTCH Set SELECTIVITY control to the 9 o clock position Adjust FREQUENCY control to remove the CW signal or heterodyne Increase SELECTIVITY clockwise to narrow the bandwidth of the notch Readjust FREQUENC...

Страница 4: ...eration It can be used to obtain very narrow bandwidths with good skirt selectivity and little ringing when the primary filter is in the peak mode or to limit the bandwidth when the primary filter is in the NOTCH LOW PASS or HIGH PASS mode NOTE When using both filters in the PEAK mode with narrow bandwidths the best skirt selectivity and least attenuation will be obtained by setting both the auxil...

Страница 5: ... and turn the SELECTIVITY and FREQUENCY controls to minimum counter clockwise 2 With high selectivity the filter may have a tendency to ring in peak and lowpass modes If this occurs decrease the selectivity 3 Due to the very high internal filter gains in the LOW PASS mode with maximum selectivity and frequency the filter may OSCILLATE If this occurs reduce SELECTIVITY and FREQUENCY controls until ...

Страница 6: ... 1V p p and adjust generator frequency control s for a null minimum amplitude Null should occur at about 3000 Hz 4 Switch Primary Function Selector to PEAK 5 Increase Primary SELECTIVITY control to maximum 6 Adjust R319 10K High Tracking trimmer for maximum amplitude 7 Set generator frequency to 500 Hz 8 Set primary SELECTIVITY control to 3 o clock 9 Set primary filter to NOTCH and adjust primary ...

Страница 7: ...6 MFJ 752D Schematic Diagram ...

Страница 8: ...is warranty is NOT void for owners who attempt to repair defective units Technical consultation is available by calling 662 323 5869 5 This warranty does not apply to kits sold by or manufactured by MFJ Enterprises Inc 6 Wired and tested PC board products are covered by this warranty provided only the wired and tested PC board product is returned Wired and tested PC boards installed in the owner s...

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