[time-nuts] WWVB Simulator
msimon6808 at yahoo.com
Wed Jan 4 16:21:22 EST 2017
A PC can certainly generate a lot of frequencies. But if you want to use the audio channels at 60KHz there is a little problem. There is a brick wall filter in the audio channel set at about 25 KHz.
Now I could set up the audio to output 15 KHz I and Q and mix it (quadrature mixer) with 45 KHz X 4 (precision source) to get 60 KHz. And then filter it to get the 60 KHz. Which requires some op amps. And filters. A precision 45 KHz source. A gray code counter (divide by 4). And stuff.
Easier to work at DC (my "audio" signal) and mix that up to 60 KHz directly. Besides. I do like designing and building hardware. Engineering is the art of making what you want from what you can get at a profit.
I like Polywell Fusion.
On Wednesday, January 4, 2017 7:48 AM, Chris Albertson <albertson.chris at gmail.com> wrote:
You don't need to tie up a PC. It could likely output the WWVB
signal while it was also surfing the web and reading emails. 60KHz
is NOTHING compared to displaying a you-tube video
In fact I bet your 48MHz uP could directly synthesize the signal.
Look at the ratio of 48 MHz / 60 KHz. The uP can execute about 800
instructions during one cycle of a 60 KHz courier. Your PC can do
a million operations during that same one cycle.
But go ahead. I'm subscribed to another list dedicated to building
stuff with vacuum tubes. I kind of enjoy building with that
technology. I used to like building with 70'd vintage 74xxx TTL.
city is like lego blocks for big kids. But as a practical matter if
you just want something to work, 21st century technology gets the job
On Tue, Jan 3, 2017 at 6:49 PM, M. Simon via time-nuts
<time-nuts at febo.com> wrote:
> Sure. I considered software. But I'm a hardware guy. I like designing boards. The rig was designed to do amplitude and phase simply. The final design will have a $5 48 MHz microprocessor included. I'm using that one because of speed and memory. When that proves out I might redesign for a $2 24 MHz processor. Onesies prices at Mouser
> Besides the hardware better illustrates the concepts than software. And I don't have to tie up a PC if I don't want to.
> I haven't priced everything out yet because the design is not done. I'd be surprised if the cost was over $20 in parts for everything - power supply not included. PCB extra.
> Feel free to send this along to the list if you are inclined.
> Engineering is the art of making what you want from what you can get at a profit.
> I like Polywell Fusion.
> On Tuesday, January 3, 2017 5:53 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
> time-nuts at febo.com said:
>> I have come up with a ridiculously simple WWVB simulator that simulates both
>> the AM modulation and the BPSK modulation.
> Did you consider software?
> Is the audio on a Raspberry Pi fast enough?
> I haven't looked at any details, but you can get ARM CPUs for ballpark of $5
> on eBay. There is a good chance that one of their IO devices will let you
> send raw bits via a DMA channel.
> These are my opinions. I hate spam.
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