--- In [email protected], FRANCIS CARCIA <[EMAIL PROTECTED]> wrote:
>
> Look at the vco control voltage with a scope. Say it is slammed against a
> rail high or
ground. This means the reference divider or the divide by N are not set up
properly.
> If it is oscillating then the filter is wrong. surf old motorola for
> special functions for
Yes, the VCO voltage is jumping up and down on the scope. I hooked up a bicolor
led
on the double ended PLL error signal pins (phi_R phi V).
>applications information. The applications will tell you how to determine the
> constants you need. Usually you set the filter corner frequency at 1/10 the
reference into the phase detector for starters. I did a 145152 in my homebrew
rx. fc
Ok, I'll test out the BW=1/10 ref frequenency (i.e. crystal freq divided by R).
Another question, I made my own prescaler in the sense I took the VCO buffered
by a
NPN follower, followed by a 74AC04 NOT gate with a feedback resistor, another
NOT
gate and finally a 74AC163 to make my prescaler to finally go in to the
MC145151,
which internally has its own NOT gate with feedback resistor. Should I be
worried
about the phase of the divided down VCO output coming into the MC145151?
Frank
>
> Frank <[EMAIL PROTECTED]> wrote:
> Hello,
> I would like some generic rule of thumb rules for a MC141515 single modulus
> PLL
> using a simple 1st order RC filter. The datasheet gives the bandwidth of the
> loop as
a
> function of the other parameters, but I don't know what it should be. How
> much
> bandwidth is enough, all I know is that my circuit does not lock? In reality,
> for an RC
> filter I need to know these values as a function of all the rest (Kphase,
> Kvco, N).
> Any advice, to teach me to fish please?
> Frank
>
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
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