KATAΣΚΕΥΗ ΓΕΝΗΤΡΙΑΣ ΣΤΕΡΕΟ ΜΕ ΑΠΙΘΑΝΟ ΔΙΑΧΩΡΙΣΜΟ 60 DB - FM STEREO GENERATOR - 60DB

 KATAΣΚΕΥΗ  ΓΕΝΗΤΡΙΑΣ ΣΤΕΡΕΟ ΜΕ ΑΠΙΘΑΝΟ ΔΙΑΧΩΡΙΣΜΟ 60 DB 

ΠΑΡΑΚΑΤΩ ΤΟ ΣΧΗΜΑΤΙΚΟ ΤΟΥ ΜΕ ΤΑ ΥΛΙΚΑ  ΚΑΙ ΟΔΗΓΙΕΣ  ΚΑΤΑΣΚΕΥΗΣ 

ΚΑΙ ΡΥΘΜΙΣΗΣ  - HI STEREO SEPARATION  UP OF 60 DB

 

R1 = R5 = 10K
R2 = R6 = 220K
R3 = R4 = R9 = 47K
R7 = R8 = 4.7K
R10 = 68K
R11 = R12 = 27K
R13 = 2.2K variable
R14 = 20K liniar
C1 = C2 = 1nF
C3 = C4 = C11 = 100nF
C5 = C10 = 10nF
C6 = 470pF
C7 = 100pF
C8 = 68pF
C9 = 10uF
L = 6.8mH
IC1 = 4066
IC2 = 4013
IC3 = 4047
IC4 = 741

To adjust the frequency rotate R13 (multiturn) untill on IC2 pin 10 you measure 19kHz or the stereo led lights up on your stereo receiver. From R10 adjust the pilot tone signal and from R7 adjust the sound level. Use metallic resistors and 100nF ceramic capacitor for low noise stereo signal.
If your audio source has dc voltage on audio output connect 2 x 0.47uF capacitor on the stereo encoder inputs. You can use a better T1 like BC549C if you want a higher sound amplification. Keep short circuits distances.
If you want the best from this mpx stereo encoder use metallic resistors, ceramic capacitor, shielded audio cables for input and MPX output and a good stabilized, filtered 5V power supply.
I’ve worked with this stereo encoder in my youth and it’s pretty good, has a 70% stereo separation.
Stereo Encoder circuit components:
R1 = R2 = 68K
R3 = R4 = 270K
R5 = 22K
R6 = 2.2K
R7 = 50K
R8 = R12 = R14 = 10K
R9 = 12K
R10 = 10K variable
R11 = 47K
R13 = 50K variable
C1 = C2 = C7 = C8 = 1nF
C3 = C4 = C5 = C9 = C10 = C12 = 100nF ceramic
C6 = 10uF
C11 = 620pF
IC1 = MMC4066E
IC2 = MMC4047
T1 = BC547B, BC549C