Posted by: Jan
« on: March 01, 2014, 09:44:33 pm »If pilot is not accessible anywhere (MPX only), you have 3 options:
Pilot filter
Input MPX level at least 1.2 Vpp. Recovered pilot is available at PLT. Signal /SNC goes low if pilot is detected.
Part list:
IC4 – LM567
IC5 – TLC272 or any opamp
L2 – 09P-152J (1.5 mH)
R17 – 2k
R19, R26 – 10k
R15, R18 – 15k
R16, R20, R21 – 33k
R28 – trimmer 5k
C6, C12, C24 – 100n (C)
C8 – 10u (E)
C9 – 100u (E)
C25 – 4n7 (P)
C21 – 3n3 (P)
C22 – 220n (P)
C23, C29 – 1n (C)
C27 – 47n (5%, P)
C28 – 330p (C)
Adjustment:
With no input signal connected, adjust 19 kHz (+/- 100 Hz) on PLT using trimmer R28. Alternatively connect the MPX to input and adjust the R28 to the position where /SNC goes low.
- Use PIRA32
- Leave it unsynchronized (suitability depends on application)
- Use the pilot filter below
Pilot filter
Input MPX level at least 1.2 Vpp. Recovered pilot is available at PLT. Signal /SNC goes low if pilot is detected.
Part list:
IC4 – LM567
IC5 – TLC272 or any opamp
L2 – 09P-152J (1.5 mH)
R17 – 2k
R19, R26 – 10k
R15, R18 – 15k
R16, R20, R21 – 33k
R28 – trimmer 5k
C6, C12, C24 – 100n (C)
C8 – 10u (E)
C9 – 100u (E)
C25 – 4n7 (P)
C21 – 3n3 (P)
C22 – 220n (P)
C23, C29 – 1n (C)
C27 – 47n (5%, P)
C28 – 330p (C)
Adjustment:
With no input signal connected, adjust 19 kHz (+/- 100 Hz) on PLT using trimmer R28. Alternatively connect the MPX to input and adjust the R28 to the position where /SNC goes low.