XTL choice for 137Hz w/ CD4046

Wed Mar 10, 2010 7:46 pm   

On 3/10/2010 12:54 PM, Joerg wrote:


Me, I'm 2 blocks from Dom & Vinnie's. New York pizza doesn't get any
better.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net

Thu Mar 11, 2010 1:08 am   

On Mar 10, 10:46 am, Phil Hobbs
<pcdhSpamMeSensel...@electrooptical.net> wrote:

You can always get a custom crystal made if this is just a one off
project. I had one made, but I found an off the shelf job that would
work. I had a custom crystal cut for $18. I had the guy call back
with the order, he said it would take a couple of days, but it took
weeks. I had already redesigned the thing and moved on.

Regards,
Chris

Thu Mar 11, 2010 1:12 am   

On Tue, 09 Mar 2010 23:22:40 GMT, donlerner_at_quantumx.com (Don Lerner)
wrote:


---
If you were to use all 14 stages, 1.122304 MHz, and for every stage
shorter than 14, the frequency would drop by a factor of 2.
---


---
1.122304 MHz isn't a commonly available frequency and neither are any of
its binary submultiples, so some trickery is in order...
---


---
Since the period of the frequency you want is:

1 1
t = --- = ------- = 7.299270007e-3s ~ 7299.27µs,
f 137Hz

then your output waveform would look something like this:

|<--------7299.27µs-------->|
_____________ _________
_____| |_____________|


4.0 MHz is a very common crystal and crystal oscillator frequency, and
since one cycle of 4 MHz is 0.25 µs, if you used that you could get to
7299.25 µs by accumulating


7299.25µs
n = ----------- = 29197
0.25µs

0.25µs clock periods.

Since we're looking for 7299.27µs and what we'll get is 7299.25µs if we
accumulate 29197 4MHz clocks, we'll have an error of 2 parts in 729927,
which is:

200
%e = -------- = 0.000274% = 27.4ppm,
729927

not too shabby.

OK, so how do we accumulate all those clocks and get a 137Hz signal with
rising and falling edges located about 50% away from each other?

By using a variable modulo divider, of course!

View in Courier:
U1
+------+
4MHz>----------|> |
| |
GND>--------+--|D15 |
| | |
+--|D14 |
| | |
Vcc>------+-|--|D13 |
| | | ^ |
+-|--|D12 3 |
| | | |
+-|--|D11 |
| | | |
| +--|D10 |
| | | |
| +--|D9 |
| | | ^ |
+-|--|D8 9 |
| | | |
| +--|D7 |
| | | |
| +--|D6 |
| | | |
| +--|D5 |
| | | ^ |
| +--|D4 0 |
| | | |
| +--|D3 |
| | |
+----|D2 |
| | | GND
+----|D1 | |
| ^ | +----|----+
+----|D0 6/7| | +--+--+ |
| |__ __| +-|D R Q|-|------>137Hz
| +-O|PE TC|-+----|> _| |
| | +------+ | U2| C Q|-+
| +-----------+ +--+--+ |
+---------------------|----+
|
GND

Here's how it works:

U1 is a 16 bit down counter (2 cascaded 40103's, for example) which,
when it counts to "0", pulls TC low, loading whatever is on the
broadside load inputs into the counter on the next positive transition
of the clock.

Since we want a 137Hz signal with (say) about a 50% duty cycle, what we
do is load the counter with hex 3905 (decimal 14597), let the counter
count down to zero, then load it with hex 3806 (decimal 14598),let it
count down again, load it with hex 38e2 again, and the cycle will repeat
forever.

When the load happens, TC goes high, toggling U2, which changes the
broadside load input on D0 so that the next time the counter counts down
to "0" it will load that value for that bit into the counter and start
counting down again.

The net result of that is that the counter counts to zero from 14597 in
one instance and then from 14598 in the other, cycling endlessly.

Since it takes one 4MHz clock to load D0, the counter actually counts
14598 clocks, then 14599 clocks, then 14598 clocks...

U2 is wired as a divide-by-two, and since its outputs toggle with every
TC it receives, "Q" will look like:


__ __ _______. . .____ _____. . ._______ _______
TC |_| |_| |_|

|<--14598 clocks-->|<--14599 clocks--->|

|<--------------29197 clocks---------->|

|<--------------7299.25µs------------->|


|<------------137.003768Hz------------>|
_______. . .______ _____
U2-Q ____| |_____. . ._________|




JF

Thu Mar 11, 2010 2:07 am   

On Wed, 10 Mar 2010 18:12:01 -0600, John Fields
<jfields_at_austininstruments.com> wrote:>




JF

Thu Mar 11, 2010 2:47 am   

On Mar 9, 3:22 pm, donler...@quantumx.com (Don Lerner) wrote:

What is the 137Hz related to?

I know 24Hz and 25Hz are film related.
50Hz and 60Hz are AC line related.

I would just program a uC for 24,25,50,60,100,120 and 137, using a 4
bits input selector. Anyone wants it for $1?

Thu Mar 11, 2010 5:55 am   

On Wed, 10 Mar 2010 13:46:26 -0500, Phil Hobbs
<pcdhSpamMeSenseless_at_electrooptical.net> wrote:


There are a couple of really good New York style pizzerias here too but I
prefer Chicago style. The thing I really miss, though, is a good diner.

Thu Mar 11, 2010 6:21 am   

Phil Hobbs wrote:

Right - but you still gotta try barbecued pizza. You won't
believe how good it is until you try it.

For size, drive north up 684 to exit 6, Golden's Bridge.
Turn right, enter shopping center on the right & get
a slice at the pizza place (whose name I forget) there.
Biggest slices I've ever seen.

Ed

Thu Mar 11, 2010 7:50 am   

On 3/11/2010 12:21 AM, ehsjr wrote:

At this point I have a 20 yard commute, and my office is 15 feet from
the fridge. Extra-large pizza slices, I do _not_ need. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net

Thu Mar 11, 2010 8:20 am   

Chris wrote:


Who makes crystals at 137 hz? The lowest I've seen was 19 KHz for a
stereo generator and it wasn't cheap, because of the size. The crystal
can was about two inches long.


--
Greed is the root of all eBay.

Thu Mar 11, 2010 9:06 am   

Joerg wrote:


This is a list of frequencies available from the Digikey website:


20.000 kHz
25.600 kHz
26.667 kHz
28.000 kHz
30.000 kHz

30.720 kHz
30.760 kHz
31.200 kHz
31.250 kHz
31.500 kHz


32.000 kHz
32.560 kHz
32.768 kHz
32.919 kHz
34.000 kHz

36.000 kHz
38.000 kHz
38.400 kHz
39.500 kHz
40.000 kHz


44.100 kHz
46.604 kHz
46.6084kHz
50.000 kHz
59.787 kHz

60.000 kHz
60.002 kHz
60.005 kHz
65.535 kHz
65.536 kHz


69.000 kHz
70.000 kHz
71.000 kHz
72.000 kHz
73.000 kHz

74.000 kHz
74.300 kHz
74.400 kHz
75.000 kHz
76.000 kHz


76.790 kHz
76.800 kHz
76.810 kHz
77.000 kHz
77.204 kHz

77.287 kHz
77.500 kHz
77.503 kHz
77.504 kHz
78.000 kHz


79.000 kHz
83.000 kHz
96.000 kHz
96.006 kHz
100.000 kHz

111.000 kHz
117.720 kHz
120.000 kHz
120.8475kHz
125.000 kHz


131.072 kHz
149.475 kHz
153.600 kHz
200.000 kHz
307.200 kHz




1.000000 MHz
1.843200 MHz
2.000000 MHz
2.048000 MHz
2.097152 MHz

2.457600 MHz
2.500000 MHz
2.560000 MHz
2.949120 MHz
3.000000 MHz


3.072000 MHz
3.276000 MHz
3.276800 MHz
3.579000 MHz
3.579545 MHz

3.640000 MHz
3.686400 MHz
3.700000 MHz
3.859000 MHz
3.932160 MHz


4.000000 MHz
4.032000 MHz
4.096000 MHz
4.096250 MHz
4.194000 MHz

4.194304 MHz
4.332000 MHz
4.433000 MHz
4.433616 MHz
4.433618 MHz


4.433619 MHz
4.500000 MHz
4.645300 MHZ
4.746870 MHz
4.800000 MHz

4.897000 MHz
4.906250 MHz
4.915000 MHz
4.915200 MHz
5.000000 MHz


5.068800 MHz
5.120000 MHz
5.185000 MHz
5.223438 MHz
5.500000 MHz

5.529600 MHz
5.848400 MHz
5.926500 MHz
5.990400 MHz
6.000000 MHz


6.144000 MHz
6.176000 MHz
6.400000 MHz
6.498300 MHz
6.500000 MHz

6.553600 MHz
6.612813 MHz
6.745800 MHz
6.757000 MHz
6.764380 MHz


7.150500 MHz
7.159090 MHz
7.200000 MHz
7.372800 MHz
7.680000 MHz

7.948880 MHz
8.000000 MHz
8.000156 MHz
8.192000 MHz
8.388608 MHz


8.432000 MHz
8.500000 MHz
8.643200 MHz
8.912000 MHz
9.000000 MHz

9.216000 MHz
9.494531 MHz
9.509375 MHz
9.545000 MHz
9.600000 MHz


9.625000 MHZ
9.794100 MHz
9.815630 MHz
9.830000 MHz
9.830400 MHz

9.843750 MHz
9.843800 MHz
10.000000 MHz
10.240000 MHz
10.245000 MHz


10.624400 MHz
10.738635 MHz
10.738650 MHz
10.781250 MHz
11.000000 MHz

11.046000 MHz
11.059200 MHz
11.228000 MHz
11.289600 MHz
11.520000 MHz


11.981350 MHz
12.000000 MHz
12.000393 MHz
12.031125 MHz
12.096000 MHz

12.187000 MHz
12.187500 MHz
12.288000 MHz
12.352000 MHz
12.500000 MHz


12.688000 MHz
12.800000 MHz
12.960000 MHz
13.000000 MHz
13.025190 MHz

13.062500 MHz
13.125225 MHz
13.225000 MHz
13.225600 MHz
13.225625 MHz


13.262250 MHz
13.491600 MHz
13.500000 MHz
13.516800 MHz
13.521270 MHz

13.548560 MHz
13.560000 MHz
13.560000 MHz
13.605000 MHz
13.824000 MHz


13.949160 MHz
14.000000 MHz
14.089190 MHz
14.276430 MHz
14.299830 MHz

14.318000 MHz
14.318180 MHz
14.335900 MHz
14.359400 MHz
14.400000 MHz


14.463660 MHz
14.500000 MHz
14.690000 MHz
14.745600 MHz
14.822520 MHz

14.850000 MHz
15.000000 MHz
15.360000 MHz
16.000000 MHz
16.000312 MHz


16.128000 MHz
16.257000 MHz
16.367600 MHz
16.368000 MHz
16.384000 MHz

16.576000 MHz
16.666000 MHz
16.667000 MHz
16.670000 MHz
16.800000 MHz


16.934000 MHz
16.934400 MHz
17.734400 MHz
17.734475 MHz
18.000000 MHz

18.080000 MHz
18.432000 MHz
18.869000 MHz
19.200000 MHz
19.440000 MHz


19.657812 MHz
19.660000 MHz
19.660800 MHz
19.680000 MHz
19.800000 MHz

20.000000 MHz
20.356250 MHz
20.356300 MHz
20.480000 MHz
21.477270 MHz


22.000000 MHz
22.118000 MHz
22.118400 MHz
22.400000 MHz
22.500000 MHz

22.579200 MHz
22.627800 MHz
23.000000 MHz
23.264300 MHz
23.500000 MHz


23.512200 MHz
23.592000 MHz
23.706250 MHz
24.000000 MHz
24.000140 MHz

24.500000 MHz
24.545454 MHz
24.553500 MHz
24.576000 MHz
24.704000 MHz


24.745600 MHz
25.000000 MHz
25.175000 MHz
25.223500 MHz
25.456250 MHz

25.456300 MHz
25.500000 MHz
26.000000 MHz
26.451250 MHz
26.451300 MHz


26.500000 MHz
26.597100 MHz
26.800000 MHz
27.000000 MHz
27.120000 MHz

27.134375 MHz
27.134400 MHz
27.200000 MHz
27.306700 MHz
27.468800 MHz


28.000000 MHz
28.224000 MHz
28.259375 MHz
28.259400 MHz
28.322000 MHz

28.375000 MHz
28.593750 MHz
28.593800 MHz
28.636000 MHz
28.636300 MHz


28.636360 MHz
29.491200 MHz
29.498928 MHz
29.500000 MHz
30.000000 MHz

32.000000 MHz
32.514000 MHz
32.768000 MHz
33.000000 MHz
33.333000 MHz


33.333300 MHz
33.868800 MHz
35.251200 MHz
35.328000 MHz
36.000000 MHz

38.000000 MHz
38.000530 MHz
38.400000 MHz
38.880000 MHz
39.000000 MHz


40.000000 MHz
40.320000 MHz
40.960000 MHz
42.000000 MHz
44.000000 MHz

44.236800 MHz
44.545000 MHz
44.736000 MHz
44.800000 MHz
44.900000 MHz


45.000000 MHz
46.000000 MHz
48.000000 MHz
49.152000 MHz
49.860000 MHz

50.000000 MHz
53.125000 MHz
54.000000 MHz
55.000000 MHz
60.000000 MHz


64.000000 MHz
66.000000 MHz
66.666000 MHz
66.666600 MHz
73.669790 MHz

75.957292 MHz
76.121875 MHz
80.000000 MHz
114.285000 MHz
161.132800 MHz


--
Greed is the root of all eBay.

Thu Mar 11, 2010 9:44 am   

On Wed, 10 Mar 2010 19:07:03 -0600, John Fields
<jfields_at_austininstruments.com> wrote:


Aarghhh... 3906

JF

Thu Mar 11, 2010 9:53 am   

John Fields wrote:


A 100 KHz crystal is only 10 cycles off. 730*137=100,010 Hz. You
should be able to pull the crystal 10 Hz.


--
Greed is the root of all eBay.

Thu Mar 11, 2010 10:47 am   

On 11/03/2010 6:06 PM, Michael A. Terrell wrote:

137 * 512 = 70.144k

an error of .2 percent. You should be able to trim that out

Thu Mar 11, 2010 10:53 am   

linnix a écrit :

Hmmm, at that rate I'll subcontract you all my programming work...


--
Thanks,
Fred.

Thu Mar 11, 2010 11:00 am   

Phil Hobbs wrote:

I work at home too. The bedroom door is 10 ft away, and since
today is a holiday, my wife - a junior officer in government
service - is home and whatever I need from the kitchen is just a
yell away. :-)

My workshop, 10 yards from the main building, is almost
completely taken over by accumulated junk - unclaimed TVs, VCRs,
etc from my repairing days, old computers from more recent times,
old projects, even a complete X-ray machine. We don't have proper
disposal and recycling facilities, and I've never yet got around
to hiring a truck to take everything to a designated dumping
ground 20 km outside town.