Hi Bert,
What kind or sort of documentation is needed?
schematics?
PC layout?
software / firmware documentation?
I've been programming PICs intermittently for 10+ years. Some of my
projects use 2 or 4 line LCD displays. I have given other
microcontrollers a short test spin.
I've also done some Verilog with the Altera DE0 nano board (Cyclone IV
EP4CE22F17), a period counter that used an internal PLL to boost the
hardware 50 MHz to 300 MHz for better resolution. Also FPGA for software
defined radio signal processing (Cyclone III).
Dave McQuate
WA8YWQ
mcqu...@sonic.net
On 11/19/2012 2:28 PM, ewkeh...@aol.com wrote:
Allow me to put all this in perspective. Three years ago having just
joined time-nuts I started to be interested in Dual Mixers. Having CS and Rb my
main interest was and still is low noise signal generators and I have all
the HP equipment for those measurements. Did my first Shera Rb about 2000
and a few more since. Time was not and still is not much of an interest my
best time instrument is a modified PICTIC II.
Starting with the original NBS paper I came to the conclusion that the
major cost would be the counter, something I would have very little use for,
for other projects since I am well equipped up to 40 GHz. That is when I
came up with the idea of what I call a ping pong counter a counter that counts
every period, sort of pseudo time stamping. Back of an envelop calculation
and I went on the list stating that I think a $ 200 D/M system not
counting OCXO’s was doable. What was needed was help with the PIC codes. First
response was “that is why we call our self Time-nuts”. However Richard Mc
Cokle did offer his help and he has been key to the success. The goal of $
200 for all material for a 4 channel counter and D/M is attainable if 10
boards are ordered.
The first set of boards where done in about 5 month. Several people tested
the D/M but kept on using their counter and my thanks go out to Corby who
tested the very first D/M.
I was left testing the counter and logic is my strong suit as Juerg will
attest my weakness is software even though at one time I set up and was in
charge of a software group. Had problems with the counter PC interface. Now
thanks to Corby I now know that the problem was the 56K RS 232 versus 9.6
K. Tells you how brilliant I am on that subject. Till recently I thought RS
232 is RS232.
I did reach out to the list and connected with Fred Tijddingen who offered
to help. I send him a counter and he asked me to get him some parts that
where not time related after he agreed to pay for them. After I shipped
them, never heard from him again. Be careful, I do not know if any one else had
that experience. Many of you know I used to ship and only asked to be paid
after you got the parts. Well now I am a lot more selective.
A year ago I connected with list member Juerg Koegel. We share the same
priorities and complement each other with our skill sets. On top of that
Juerg has the equipment that I lack and the know how to make it talk to PC’s.
On top of that Juerg had used a MAX 3000 G/A for a PICTIC counter. Perfect
match. Juerg can also write PIC code, not like Richard but what we need.
First out the 2 channel and 4 channel counters now with G/A’s and Richards
PIC;s. The two channel measures phase and period in the ping pong mode
allowing you to do the basics of a single D/M. The 4 channel was intended for
two D/M’s or with an additional 2 channel for three corner hat. Can also be
used for cross correlation.
How ever the 4 channel in combination with one D/M allows also very high
resolution frequency comparison only limited by the noise floor of the D/M.
Since the A/V measurements are most likely not a daily activity using this
instrument for frequency measurements or aging tests over long term makes
it a very useful tool. Juerg does not want me to talk to much about it, but
he is right now busy writing PIC code for a 4 line LCD display that also
includes a Vinculum VDRIVE2 that allows recording data on a USB flash drive,
interfaces with a PC using RS 232, USB and Bluetooth. I call it the Swiss
Army Knife, because of all the things the combination D/M, Counter and Juerg
LCD can do.
The D/M is being revisited because of the counter performance. 1 E-13 is
easily attainable but the Czech IREE published a paper and claim 2 E-15.
Would be nice to get 1 E-14. Tried to get detailed information, no luck, but
maybe some list member will be able to. It was EU funded.
Working with Juerg has been very productive
2 channel counter done
4 channel counter done
Partridge and TADD-2 Mini like 1 pps generator using G/A done
Tbolt Bluetooth interface done
G/A version of Shera using 100 or 200 MHz in testing
D/M LCD PCB done, in code writing phase
Austron circuit using G/A in testing
PICTIC II using G/A in board layout G/A done
At this point I like to make a plug for the Altera MAX 3000 GA. Easy to
program (I can do it) low cost and makes all TTL and HC logic available but
the best part if something does not work you do not have to do a new board,
just reprogram. Using a $ 0.60 socket makes it very solderable. Made a
prototype board and I think it is fair to say that our productivity has gone up
10 fold. Some one mentioned G/A jitter a day later we had a test setup
comparing a Partrige board with our circuit and found out thanks to Jueg’s
equipment G/A was as good maybe slightly better. Software is free and the prog
rammer is $ 10.
What happens next depends on interest by the list. Juerg and I will not
get in to the kit business but if larger interest is there I will find a way
to accommodate.
Let me make it clear, the counter by it self has only limited usability,
you also have to have or build a D/M. But the combination with a PC or
Display will make it a very useful, flexible, affordable tool.
My back of the envelope calculation still shows $ 200 for the Mixer und
counter and somewhere between $ 350 and 400 for a full up system using Morion
MV 89 OCXO for offset, LCD Display with VDRIVE2, power supplies and
enclosure.
I am looking for a volotier to work with me on the documentation, my
drafting skills are mnimal and I want Juerg to focus on display code. Would be
a
distraction.
Will send a picture of the 2 channel but have to compress to make it
through the system.
Bert Kehren Miami
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