1khz is 20% of 5 kHz so is a reasonable lock range from 4,5khz to 5,5khz
10% would be 500hz
And 2% 100hz
And so on
The pll locks in phase so although the lock range is 2% it only means it will seek in that range but once locked the precision will be of the phase lag only…
The importance of having this control is to be able to skip the non desired resonance!
Also if the Q factor is too high having a vast lock range would leave too little time for the different frequencies to cause effect and resposnse in time
So basically the off set will be the most important button so it can be a multi turn with locking screw if possible…!!!!
Specially to work in a car subjected to vibration
I’m currently using a trim por for the bandwidth resistor so basically setting it make the bandwidth fixed
When dividing by 10 it also divide by 10…
So I plan to use 100 10 1 and lastly a variable capacitance for the last cycle… that way it can be varied in frequency and bandwidth at same time
I think 10hz for the last range may be just enough so I’m going for something like
10000 1000 100 10 hz
So the manual or scanning ckt tuning should go for example from 100hz to 10,1khz up to 100khz to 110khz with off set
Likely in The second case would go from 100 to 1100 hz up to 100khz to 101khz
And so on
Of course if required just need to adjust the trim pot for more or less band
But this seem an acceptable range for working on this given my experience
The hc7046 have an internal ckt for the lock so I just need to add a capacitor… a selector could be used for it and for also the filter to allow use for multiple frequencies
But again as this is not really the case… but if constructing an equipment that could go from 1khz to 1mhz filter and lock capacitor must be also selected
From 1khz to 50khz it may not be necessary… or not too necessary
I’m pretty happy with the results already the pcb makes a very huge difference in stability and also workability