Hi all
I would like to do a frequency multiplier synchronized to the frequency of the mains (i.e. 50Hz)
I am using an old(but gold) HCF4046, I have read several data sheets, application notes but I am still stuck.
Here are the parameter
R1 = 10kOhm
C1 = 2.2nF
Vcc = 5V
-Vcc = -5V
so the central frequency is around 20kHz
I am using a divider between VCOout - COMPARATORin, a HEF4040, for now just to divide by 256.
I am using Phase Comparator 2 and between PhaseCompIIout and VCOin I have an active loop filter:
The problem is that no matter the filter I am using (tried also a lead-lag passive filter) the output frequency is not stable at 12800Hz but it somehow oscillates and the most surprising fact is that with the passive filter it had an oscillation of around +-2Hz around 12800Hz while with the active filter it is even worse.
It's a long time and finally I decided to ask for some help, have you any suggestion/hints?
I would like to do a frequency multiplier synchronized to the frequency of the mains (i.e. 50Hz)
I am using an old(but gold) HCF4046, I have read several data sheets, application notes but I am still stuck.
Here are the parameter
R1 = 10kOhm
C1 = 2.2nF
Vcc = 5V
-Vcc = -5V
so the central frequency is around 20kHz
I am using a divider between VCOout - COMPARATORin, a HEF4040, for now just to divide by 256.
I am using Phase Comparator 2 and between PhaseCompIIout and VCOin I have an active loop filter:
The problem is that no matter the filter I am using (tried also a lead-lag passive filter) the output frequency is not stable at 12800Hz but it somehow oscillates and the most surprising fact is that with the passive filter it had an oscillation of around +-2Hz around 12800Hz while with the active filter it is even worse.
It's a long time and finally I decided to ask for some help, have you any suggestion/hints?