Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-03 Thread Dennis Ferguson
On 3 Feb, 2012, at 14:15 , Orin Eman wrote: On Thu, Feb 2, 2012 at 7:16 PM, Hal Murray hmur...@megapathdsl.net wrote: It's possible to use Bresenham with two integers 10,000,000 and 32,768 but I found no way to perform all the 24-bit calculations on an 8-bit PIC quick enough. Removing

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-03 Thread Orin Eman
On Fri, Feb 3, 2012 at 1:08 AM, Dennis Ferguson dennis.c.fergu...@gmail.com wrote: On 3 Feb, 2012, at 14:15 , Orin Eman wrote: On Thu, Feb 2, 2012 at 7:16 PM, Hal Murray hmur...@megapathdsl.net wrote: It's possible to use Bresenham with two integers 10,000,000 and 32,768 but I

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-03 Thread Hal Murray
t...@leapsecond.com said: I'm curious how a 10 MHz-driven high-end DDS would generate 32 kHz with the lowest possible jitter? What do you mean by high-end DDS? A chip from Analog Devices or one from Xilinx? :) If you use a classic DDS chip with a binary adder and ROM, it will have low

[time-nuts] 32768 Hz from 10 MHz

2012-02-02 Thread Brooke Clarke
Hi Roberto: By changing the timer count dynamically it's possible to lower the jitter to one timer count. See: http://www.prc68.com/I/PClock.shtml#BA Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html Roberto Barrios wrote: Hi Tom, I'm

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-02 Thread Tom Van Baak
Hi Roberto: By changing the timer count dynamically it's possible to lower the jitter to one timer count. See: http://www.prc68.com/I/PClock.shtml#BA Have Fun, Brooke Clarke Hi Brooke, You're a fellow PIC guy; let me explain. Correct, that method works with a modest interrupt rate to

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-02 Thread Chris Albertson
On Thu, Feb 2, 2012 at 12:21 PM, Tom Van Baak t...@leapsecond.com wrote: I'm curious how a 10 MHz-driven high-end DDS would generate 32 kHz with the lowest possible jitter? I wonder if your 32K diver could be improved if it used interpolation. In other words use an analog output. So at

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-02 Thread Azelio Boriani
Now I'm thinking that starting with a first run of 8 cycles at 500nS + 2 cycles at 400nS to be repeated for 10 times and then inserting 2 cycles of 400nS, a first approximation of my 2.048MHz can be done. Maybe with a deltaF/F of 10 at -4 for tau 1 second but it can be done. In the very long run

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-02 Thread Brooke Clarke
Hi Tom: I like the leap year idea. Does this fit into one of the 8-pin PICs? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html Tom Van Baak wrote: Hi Roberto: By changing the timer count dynamically it's possible to lower the jitter to

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-02 Thread Hal Murray
It's possible to use Bresenham with two integers 10,000,000 and 32,768 but I found no way to perform all the 24-bit calculations on an 8-bit PIC quick enough. Removing the GCD often helps but in this case the accumulator remains 3-bytes wide. To generate 32 kHz you have to toggle a pin and

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-02 Thread Dave Martindale
On Thu, Feb 2, 2012 at 12:21, Tom Van Baak t...@leapsecond.com wrote: It's possible to use Bresenham with two integers 10,000,000 and 32,768 but I found no way to perform all the 24-bit calculations on an 8-bit PIC quick enough. Removing the GCD often helps but in this case the accumulator

Re: [time-nuts] 32768 Hz from 10 MHz

2012-02-02 Thread Orin Eman
On Thu, Feb 2, 2012 at 7:16 PM, Hal Murray hmur...@megapathdsl.net wrote: It's possible to use Bresenham with two integers 10,000,000 and 32,768 but I found no way to perform all the 24-bit calculations on an 8-bit PIC quick enough. Removing the GCD often helps but in this case the