Just checking, from the datasheet of the MC145151-2 (page 17), the PDout signal is a pulsating signal between VL and VH. I just wanna make sure that VL is 0V and VH is 5V (assuming a 5V VCC) and that it stays at around 2.5V when frequency locking occurs. I wanna make sure since the VCO takes a positive input tuning voltage and it would be perfect if the Pdout levels are as I think they are since the VCO gives around 315MHz at a tuning voltage of 2.5V. I'm asking because it says in the datasheet of the MC145151 that the PDout gives either positive or negative pulses depending on the correction that needs to be made (page 4). I just hope that 'negative' is not literally negative. Please take a look at the datasheet if you can and confirm my interpretation.
Thanks a lot.
Nichola