Freescale fractional clock divider paper

> 
> It's a while since I played with such things but could one not just feed the signal to an oscillator running at around 1/2.5th the frequency and have it lock. With the right amplitude it should lock on the voltage extremes but not the centre voltage of the osc input.
> 

double it then integer divide

m

On Wed, 29 Nov 2017 07:48:19 -0800 (PST), makolber@yahoo.com wrote:

>
>> 
>> It's a while since I played with such things but could one not just feed the signal to an oscillator running at around 1/2.5th the frequency and have it lock. With the right amplitude it should lock on the voltage extremes but not the centre voltage of the osc input.
>> 
>
>double it then integer divide
>
>m

Which is what I said in...

Message-ID: <g8qr1d1abqeod0qh19daa82upmcv83ig3c@4ax.com>

From my post,

Message-ID: <mdor1d12s5lcklcfgmd0k21odnv6s0cu4t@4ax.com>  

Drive U1A:A from 3.579545... Run U1A:Y thru a DIV455

(Only 1st D-flop is needed.)

I guess bitrex needs it built and handed to him on a platter ?>:-}
		
                                        ...Jim Thompson
-- 
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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     It's what you learn, after you know it all, that counts.

bitrex <bitrex@de.lete.earthlink.net> wrote:
> On 11/29/2017 06:46 AM, Rob wrote:
>> bitrex <bitrex@de.lete.earthlink.net> wrote:
>>> I'm hoping to use a colorburst xtal oscillator and divide it down by
>>> 227.5 to get the horizontal NTSC line frequency without the use of a
>>> fractional PLL (which I don't have the hardware to implement in the
>>> device I have to use)
>> 
>> Are they still using NTSC and designing new stuff for it?
>> 
>
> Who's "they"? Lots of stuff still has NTSC/PAL composite video inputs
> and as long as that's the case there will probably be a need for stuff
> with composite video outputs. The fact that with "modern" displays the
> signal is just fed to an ADC immediately and processed digitally is 
> irrelevant - it still needs to have the correct timing/sync pulses.

Well, the same stuff probably has RGB, Composite or digital inputs
as well, and will provide a much better picture when those are used.

I really can't see a use of NTSC (or PAL, for that matter) in the modern
world.  Yes, people clinging on to their old TV set may be using it on
cable (transmitters have been shut down over a decade ago here), but
using it for equipment-monitor connections is a bit weird.

On Wednesday, November 29, 2017 at 3:07:07 PM UTC-5, Rob wrote:
> bitrex <bitrex@de.lete.earthlink.net> wrote:
> > On 11/29/2017 06:46 AM, Rob wrote:
> >> bitrex <bitrex@de.lete.earthlink.net> wrote:
> >>> I'm hoping to use a colorburst xtal oscillator and divide it down by
> >>> 227.5 to get the horizontal NTSC line frequency without the use of a
> >>> fractional PLL (which I don't have the hardware to implement in the
> >>> device I have to use)
> >> 
> >> Are they still using NTSC and designing new stuff for it?
> >> 
> >
> > Who's "they"? Lots of stuff still has NTSC/PAL composite video inputs
> > and as long as that's the case there will probably be a need for stuff
> > with composite video outputs. The fact that with "modern" displays the
> > signal is just fed to an ADC immediately and processed digitally is 
> > irrelevant - it still needs to have the correct timing/sync pulses.
> 
> Well, the same stuff probably has RGB, Composite or digital inputs
> as well, and will provide a much better picture when those are used.
> 
> I really can't see a use of NTSC (or PAL, for that matter) in the modern
> world.  Yes, people clinging on to their old TV set may be using it on
> cable (transmitters have been shut down over a decade ago here), but
> using it for equipment-monitor connections is a bit weird.

We use video camera's and monitors to 'see' into the NIR.  Fortunately
there is still a big consumer market.. (so things are cheap) Back-up 
video monitors for cars and trucks.

George H. 

On Wednesday, November 29, 2017 at 12:07:07 PM UTC-8, Rob wrote:

> I really can't see a use of NTSC (or PAL, for that matter) in the modern
> world.  Yes, people clinging on to their old TV set...

One use is for closed-circuit television.   To make a simple camera-wire-display
ensemble.

DVI is short-wire-only (ditto HDMI and DisplayPort)
USB options are driver-crippled and short-wire-only
IP variants don't function in real-time
VGA takes too many wires, and there's no camera so equipped
ATSC encoders aren't available in a camera: that digital
    transmission standard is fast to DECODE, but not to ENCODE.

Find something OTHER than composite video that can drive a
 20-meter video link, which doesn't delay to boot an operating system
and navigate the internet.   Tell me that the cable it uses is as easy
to buy as BNC-terminated coax.  Tell me that the cameras and monitors
are interchangeable with multiple vendors.

Composite video is sometimes the only candidate.

On 11/29/2017 11:37 AM, Jim Thompson wrote:
> On Wed, 29 Nov 2017 07:48:19 -0800 (PST), makolber@yahoo.com wrote:
> 
>>
>>>
>>> It's a while since I played with such things but could one not just feed the signal to an oscillator running at around 1/2.5th the frequency and have it lock. With the right amplitude it should lock on the voltage extremes but not the centre voltage of the osc input.
>>>
>>
>> double it then integer divide
>>
>> 
> 
> Which is what I said in...
> 
> Message-ID: <g8qr1d1abqeod0qh19daa82upmcv83ig3c@4ax.com>
> 
>  From my post,
> 
> Message-ID: <mdor1d12s5lcklcfgmd0k21odnv6s0cu4t@4ax.com>
> 
> Drive U1A:A from 3.579545... Run U1A:Y thru a DIV455
> 
> (Only 1st D-flop is needed.)
> 
> I guess bitrex needs it built and handed to him on a platter ?>:-}
> 		
>                                          ...Jim Thompson
> 
I noticed that it looks like the designers of this FPGA were thoughtful 
enough to bury an edge-detection functional block way down in the manual 
that can be configured to fire on the rising and falling edges of a 
clock simultaneously, thank you for your kind offer, though! ;-)

For reference here's the patent where a logic configuration similar to 
what it looks like the writers in the original paper (which I still 
don't follow) are talking about is described:

<http://www.google.si/patents/US5335253>

On Wed, 29 Nov 2017 13:44:12 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:

>On Wednesday, November 29, 2017 at 12:07:07 PM UTC-8, Rob wrote:
>
>> I really can't see a use of NTSC (or PAL, for that matter) in the modern
>> world.  Yes, people clinging on to their old TV set...
>
>One use is for closed-circuit television.   To make a simple camera-wire-display
>ensemble.
>
>DVI is short-wire-only (ditto HDMI and DisplayPort)
>USB options are driver-crippled and short-wire-only
>IP variants don't function in real-time
>VGA takes too many wires, and there's no camera so equipped
>ATSC encoders aren't available in a camera: that digital
>    transmission standard is fast to DECODE, but not to ENCODE.
>
>Find something OTHER than composite video that can drive a
> 20-meter video link, which doesn't delay to boot an operating system
>and navigate the internet. 

FPD-Link?

>Tell me that the cable it uses is as easy
>to buy as BNC-terminated coax.  Tell me that the cameras and monitors
>are interchangeable with multiple vendors.
>
>Composite video is sometimes the only candidate.

Yep.  Good enough is usually good enough.

makolber@yahoo.com wrote:
>
>>
>> It's a while since I played with such things but could one not just feed the signal to an oscillator running at around 1/2.5th the frequency and have it lock. With the right amplitude it should lock on the voltage extremes but not the centre voltage of the osc input.


  4X colorburst crystals are easy to find, and cheap. 14.318180 MHz. 
They were common in a lot of video equipment.

On Thursday, 30 November 2017 06:22:36 UTC, Michael Terrell  wrote:
> NT wrote:

> >> It's a while since I played with such things but could one not just feed the signal to an oscillator running at around 1/2.5th the frequency and have it lock. With the right amplitude it should lock on the voltage extremes but not the centre voltage of the osc input.
> 
> 
>   4X colorburst crystals are easy to find, and cheap. 14.318180 MHz. 
> They were common in a lot of video equipment.

> > My memory says no, only whole multiples, but I can't think of any reason why. 

maybe no-one can answer the question :)


NT

On 11/29/2017 04:44 PM, whit3rd wrote:
> On Wednesday, November 29, 2017 at 12:07:07 PM UTC-8, Rob wrote:
> 
>> I really can't see a use of NTSC (or PAL, for that matter) in the modern
>> world.  Yes, people clinging on to their old TV set...
> 
> One use is for closed-circuit television.   To make a simple camera-wire-display
> ensemble.
> 
> DVI is short-wire-only (ditto HDMI and DisplayPort)
> USB options are driver-crippled and short-wire-only
> IP variants don't function in real-time
> VGA takes too many wires, and there's no camera so equipped
> ATSC encoders aren't available in a camera: that digital
>      transmission standard is fast to DECODE, but not to ENCODE.
> 
> Find something OTHER than composite video that can drive a
>   20-meter video link, which doesn't delay to boot an operating system
> and navigate the internet.   Tell me that the cable it uses is as easy
> to buy as BNC-terminated coax.  Tell me that the cameras and monitors
> are interchangeable with multiple vendors.
> 
> Composite video is sometimes the only candidate.
> 

I think "Rob" might be confusing composite with RF-modulated composite, 
like you'd plug into the antenna jack of an old tube TV set and select 
channel 3 or channel 4. I'm not modulating anything, just baseband video 
+ sync. The cable with the yellow plug.