GC_ET_Schem.html

2019-10-23   13:42:03


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--- a Simple Collection of Project Schematics ---
     This page loads slowly 
 
for developmental details goto the specific pages for each schematic (click)

*** 

 

1.  Pre-Amp
2.  Roofing-Triad Differential Filter 
3.  Active-Log_limiter 
4.  Quad-MFB audio filter , variable f()
5.  Double-Notched Differential-Phase Filter
6.  Sharp Q20 MFB variable Filter
6.  Audio out 0.5 W class-B 

 

   Each module presented can be constructed on a proto-board

    and used as a stand-alone circuit.
Intra-State impedances are well matched
Standard  Signal  Input/Output  is 1 V audio


 
for developmental details goto the specific pages for each schematic (click) 

 

 

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 Summary:
This is a Research Project about  Phase-Filters for Narrow Channel CW reception,

 

   This is a Study about Differential Phase-Filters and includes these topical sections : 
    Roofing Triad Filter    &
   Active Log-Limiter    &    MultiFeedBack Filters    &   Differential Phase Filters   &   Audio Amp.           

       *** 
       *** Designed for Easy Construction and Easy tuning and Superior CW audio filtering.
       *** Constructed and used daily for Amateur Radio CW (morse code) Operations on the Radio Bands. 
       *** The AFX CW audio filtering has near Digital Signal Processing quality as presented to the Ear.
      *** The vintage  LM324 OpAmp was chosen because the project frequency response and gain requirements are within bounds.

       *** Note that OpAmp null and balance trim-pots are not shown, and common by-pass caps not shown. 
       *** (1) for simplification
       *** (2) circuit designs are self-balancing and produce symetrical waveforms.
     

  _

Left is a Magnitude Plot of a typical  Dual-Notch Circuit.                           Right is a Bode Plot of a typical PassBand group. 


                                               AFX_Fx4-Dif-Int-pFXTRA-6-M-sq.jpg     

AFX_RLFA-v9-paged-1-B-all-ani-00.gif 

 





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This is the basic equation for the Multiple-FeedBack active filter which is used dominantly. 
Advantages are simple f(0) variation, which allows easy alignment of filters. 
R(2) is the only component that needs adjustment for a +/- 20% change.
    [Q will change only as the square-root of the delta-f(). ] 

MFB_BPF_equations_TI_.png

################################################## 

   the   AFX  B.A.S.I.C.  Schematic
(first version) 

  
AFX_BASIC-v1-7-S.png

  

****************************************************************************************************************************
 the   
 AFX'V'   Single Roof Filter   Schematic 
with Narrow Dual-Notch and Wide-Integrated Stages
Early version  
AFX_1RLFADIQ-v10-S.png


===========================================================================

 the    AFX'V'  with  Variable f() PassBand   Schematic  (Best of Class)
with Manual controlled Variable f(0)
Three Roof Filters
(advanced version)  


 

 


AFV-3RL-V4F-D-VQ-Man-S.png
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 the    AFX'V'  with Variable f() PassBand     (Best of Class)
with jFET controlled Variable f(0) and Three Roof Filters
(advanced version)

AFV-3RL-V4F-D-VQ-Fet-S.png

**************************************************************************************************************************

 

the   AFX  Roofing-Triad-Filter

 

AFX_1RTF-S.png

 

 

the   AFX  Active Limiter 

 

AFX_RLFADIQB-v10-pLIMITER-S.png

 

 

 

 

 

 

 

 

the  AFX  Quad-MFB Filter details
Multi-FeedBack Active Filter Standard
(early basic version) 

AFX_RLFADIQB-v10-pFQUAD-S.png

 

the   AFX  Differential-Phase Filter  and Q20 Sharp filter

 

AFX_RLFADIQB-v10-pFXTRA-S.png

 

 

 

 

The AFX Audio Driver
(with forced 3rd harmonic distortion) 

 

AFX_RLFADIQB-v10-pAUDIO-S.png

 



  ******* Manual Tuning  via Four 5K panel mounted pots. 
    ******* designed to control all four Filter f(0), manually, for initial set-up.

       AFV-3RL-V4F-D-VQ-Man-S.png


 


*** AFV_3RL-v2F-vQ-v1-S  design : 

***  (1) with Three Roof Filters 
***  (2) with only Two MFB filter stages ( not sufficient for dual notch )
***  (3) with R(freq) controlled by a Two-Gang Pot 
***

AFV_3RL-v2F-vQ-v1-S.png

 

 

 

Schematic shows
24 All-Pass filters
used to
replace two MFB Active PassBand Filters

*** results are Very Good

AP24-Notch-S-Hi-Lo-317-5.png



Schematic shows
8 All-Pass filters
used to replace two MFB Active PassBand Filters

*** results are Usable, OK.
*** Compared to the "AFV-3RL-V4F-D-VQ" version
(1) BW @ -3dB is wider ; 160 Hz vs 80 Hz.
(2) Dual Notch BW is wider ; 380 Hz vs 330 Hz.
(3) Variability of f(0) is much narrower ; +/- 50 Hz  vs +/- 100 Hz 

                             AFX-F8AFQ-S.png



 

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