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From: Chris on 1 Mar 2010 21:55
On Feb 28, 10:20 pm, Chris <christopher.man...(a)gmail.com> wrote:
> On Feb 28, 6:46 pm, Mark <makol...(a)yahoo.com> wrote:
>
>
>
> > On Feb 28, 10:25 am, Chris <christopher.man...(a)gmail.com> wrote:
>
> > > I bread boarded my PLL yesterday.  I was able to get it to lock just
> > > fine on a multivibrator  running at 33Hz.  I was able to solve the
> > > jitter problem by using a very large value for C1 (1000u).  However,
> > > when I attached my cameras to the loop, (one running at 22.2fps and
> > > the other running at 25fps) the loop would lock at a frequency
> > > slightly above the camera speed ~39Hz.  The camera has a contact that
> > > closes ~5ms every frame advance.  I tried using the contact to pull to
> > > ground, and to pull to rail.  I got the same result either way.  Any
> > > suggestions?
>
> > > Thanks,
> > > Chris Maness
>
> > low pass filter the ref signal coming from the camera contacts, there
> > may be bounce and the PLL is correctly locking to the "higher
> > frequency" as it sees those extra edges.
>
> > Mark
>
> That sounds like a good Idea.  What would be a good cutoff frequency?
>
> Chris

I used a .06u and a 1k resistor for a LP filter and it increased the
lock frequency. Strange. However, if I divide by another two I am
close to the camera frequency (only 1 Hz off). Still testing it
against my 33Hz multivibrator gives me 2112/2^6=33. The loop divider
is running at 2^6=64, so working perfectly with the multivibe test
circuit.

Regards,
Chris Maness
From: JosephKK on 2 Mar 2010 00:32
On Sun, 28 Feb 2010 22:20:44 -0800 (PST), Chris <christopher.maness(a)gmail.com> wrote:

>On Feb 28, 6:46 pm, Mark <makol...(a)yahoo.com> wrote:
>> On Feb 28, 10:25 am, Chris <christopher.man...(a)gmail.com> wrote:
>>
>> > I bread boarded my PLL yesterday.  I was able to get it to lock just
>> > fine on a multivibrator  running at 33Hz.  I was able to solve the
>> > jitter problem by using a very large value for C1 (1000u).  However,
>> > when I attached my cameras to the loop, (one running at 22.2fps and
>> > the other running at 25fps) the loop would lock at a frequency
>> > slightly above the camera speed ~39Hz.  The camera has a contact that
>> > closes ~5ms every frame advance.  I tried using the contact to pull to
>> > ground, and to pull to rail.  I got the same result either way.  Any
>> > suggestions?
>>
>> > Thanks,
>> > Chris Maness
>>
>> low pass filter the ref signal coming from the camera contacts, there
>> may be bounce and the PLL is correctly locking to the "higher
>> frequency" as it sees those extra edges.
>>
>> Mark
>
>That sounds like a good Idea. What would be a good cutoff frequency?
>
>Chris

You do not want a cutoff frequency but instead 74hc123 dual one shot
and a quad 2 input nand gate.
The circuit is then in three parts a 10 ms debounce pair that cross inhibit
and an rs flip-flop made from two sections of the nand gate.

Waveforms: (|||| means switch bouncing)

in ___||||--------------||||||_______________||||||------

ss1 ___|----------|___________________________|-----------

ss2 _____________________|-----------|____________________

ff ___|-----------------|____________________|-----------


^^ ss1 inhibits ss2 ^^ ss1 inhibits ss2
^^ ss2 inhibits ss1


^ ss1 sets ff ^ ss2 resets ff ^ss1 sets ff

Synchronized and nice and clean for the PFD.
From: Bitrex on 2 Mar 2010 06:03
JosephKK wrote:
> On Sun, 28 Feb 2010 22:20:44 -0800 (PST), Chris <christopher.maness(a)gmail.com> wrote:
>
>> On Feb 28, 6:46 pm, Mark <makol...(a)yahoo.com> wrote:
>>> On Feb 28, 10:25 am, Chris <christopher.man...(a)gmail.com> wrote:
>>>
>>>> I bread boarded my PLL yesterday. I was able to get it to lock just
>>>> fine on a multivibrator running at 33Hz. I was able to solve the
>>>> jitter problem by using a very large value for C1 (1000u). However,
>>>> when I attached my cameras to the loop, (one running at 22.2fps and
>>>> the other running at 25fps) the loop would lock at a frequency
>>>> slightly above the camera speed ~39Hz. The camera has a contact that
>>>> closes ~5ms every frame advance. I tried using the contact to pull to
>>>> ground, and to pull to rail. I got the same result either way. Any
>>>> suggestions?
>>>> Thanks,
>>>> Chris Maness
>>> low pass filter the ref signal coming from the camera contacts, there
>>> may be bounce and the PLL is correctly locking to the "higher
>>> frequency" as it sees those extra edges.
>>>
>>> Mark
>> That sounds like a good Idea. What would be a good cutoff frequency?
>>
>> Chris
>
> You do not want a cutoff frequency but instead 74hc123 dual one shot
> and a quad 2 input nand gate.
> The circuit is then in three parts a 10 ms debounce pair that cross inhibit
> and an rs flip-flop made from two sections of the nand gate.
>
> Waveforms: (|||| means switch bouncing)
>
> in ___||||--------------||||||_______________||||||------
>
> ss1 ___|----------|___________________________|-----------
>
> ss2 _____________________|-----------|____________________
>
> ff ___|-----------------|____________________|-----------
>
>
> ^^ ss1 inhibits ss2 ^^ ss1 inhibits ss2
> ^^ ss2 inhibits ss1
>
>
> ^ ss1 sets ff ^ ss2 resets ff ^ss1 sets ff
>
> Synchronized and nice and clean for the PFD.


That's a neat trick. If I understand the diagram correctly I think you'd
need to invert the output of the one shots first though, since
a NAND latch is active low. The other two gates in the package could be
used for that.
From: Chris on 2 Mar 2010 10:33
On Mar 1, 9:32 pm, "JosephKK"<quiettechb...(a)yahoo.com> wrote:
> On Sun, 28 Feb 2010 22:20:44 -0800 (PST), Chris <christopher.man...(a)gmail..com> wrote:
> >On Feb 28, 6:46 pm, Mark <makol...(a)yahoo.com> wrote:
> >> On Feb 28, 10:25 am, Chris <christopher.man...(a)gmail.com> wrote:
>
> >> > I bread boarded my PLL yesterday.  I was able to get it to lock just
> >> > fine on a multivibrator  running at 33Hz.  I was able to solve the
> >> > jitter problem by using a very large value for C1 (1000u).  However,
> >> > when I attached my cameras to the loop, (one running at 22.2fps and
> >> > the other running at 25fps) the loop would lock at a frequency
> >> > slightly above the camera speed ~39Hz.  The camera has a contact that
> >> > closes ~5ms every frame advance.  I tried using the contact to pull to
> >> > ground, and to pull to rail.  I got the same result either way.  Any
> >> > suggestions?
>
> >> > Thanks,
> >> > Chris Maness
>
> >> low pass filter the ref signal coming from the camera contacts, there
> >> may be bounce and the PLL is correctly locking to the "higher
> >> frequency" as it sees those extra edges.
>
> >> Mark
>
> >That sounds like a good Idea.  What would be a good cutoff frequency?
>
> >Chris
>
> You do not want a cutoff frequency but instead 74hc123 dual one shot
> and a quad 2 input nand gate.
> The circuit is then in three parts a 10 ms debounce pair that cross inhibit
> and an rs flip-flop made from two sections of the nand gate.
>
> Waveforms:   (||||  means switch bouncing)
>
> in    ___||||--------------||||||_______________||||||------
>
> ss1   ___|----------|___________________________|-----------
>
> ss2   _____________________|-----------|____________________
>
> ff    ___|-----------------|____________________|-----------
>
>           ^^ ss1 inhibits ss2                    ^^ ss1 inhibits ss2
>                            ^^ ss2 inhibits ss1
>
>           ^ ss1 sets ff    ^ ss2 resets ff      ^ss1 sets ff
>
> Synchronized and nice and clean for the PFD.

One strange thing though is I am not seeing the bounce on my scope. I
am not sure it is there unless it is beyond the frequency range of my
scope. I will check it out a little more carefully tonight.

Chris
From: Jim Thompson on 2 Mar 2010 18:02
On Sun, 28 Feb 2010 07:25:56 -0800 (PST), Chris
<christopher.maness(a)gmail.com> wrote:

>I bread boarded my PLL yesterday. I was able to get it to lock just
>fine on a multivibrator running at 33Hz. I was able to solve the
>jitter problem by using a very large value for C1 (1000u). However,
>when I attached my cameras to the loop, (one running at 22.2fps and
>the other running at 25fps) the loop would lock at a frequency
>slightly above the camera speed ~39Hz. The camera has a contact that
>closes ~5ms every frame advance. I tried using the contact to pull to
>ground, and to pull to rail. I got the same result either way. Any
>suggestions?
>
>Thanks,
>Chris Maness

Take a look at the following solutions to severely bouncing inputs...

http://analog-innovations.com/SED/AlternatingEdge.pdf

http://analog-innovations.com/SED/AlternatingEdge-Unobtanium.pdf

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
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