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wwvb receiver chip needed
I need a Temic U4224B chip, which is used for reception of DCF and
WWVB time signals at vlf. Are these available without going to Europe? Thanks, A |
Hello Albert,
I need a Temic U4224B chip, which is used for reception of DCF and WWVB time signals at vlf. Are these available without going to Europe? I am not sure you can get them at all. It might have been obsoleted by now. Regards, Joerg http://www.analogconsultants.com |
In article ,
Joerg wrote: Hello Albert, I need a Temic U4224B chip, which is used for reception of DCF and WWVB time signals at vlf. Are these available without going to Europe? I am not sure you can get them at all. It might have been obsoleted by now. In any case, Temic was bought out by Atmel. Mark Zenier Washington State resident |
Hello Mark,
In any case, Temic was bought out by Atmel. I believe Atmel called this chip T4224 but when looking for it on their web site it ain't there. Regards, Joerg http://www.analogconsultants.com |
The "usual" way of getting a WWVB receiver chip is to buy a cheap WWVB
clock and rip out the chip and antenna. Some have external chips/antenna connected via cable already. A web page showing how to do this with a commonly available Sony WWVB clock is at: http://www.leapsecond.com/pages/sony-wwvb/ Tim. |
Hello Tim,
The "usual" way of getting a WWVB receiver chip is to buy a cheap WWVB clock and rip out the chip and antenna. Some have external chips/antenna connected via cable already. Agree. Many like the Sony even contain two crystals. These alone can cost more than a whole clock. But if it's a matter of pride you can build your own even without any special chips. When I was a kid I built a receiver for DCF in Europe. No crystals, only a few transistors and 741 opamps. It worked great, except that I didn't have a PC or anything to decode the signal with. It was just the detected pulses but these came through nice and clear. With today's opamps you wouldn't even need any transistors to do it. A decent quad can be had for 50c while I paid a whopping $3 for a single re-labeled 741 of rather dubious quality level. Regards, Joerg http://www.analogconsultants.com |
Thanks for this info. Unfortunately, Atmel doesn't make the T4334 now.
But, while searching the site for keywords, I found the ATA5283 and ATA5282 125 khz receiver chips that draw less than 4 microamps while listening. I don't think there is anything inside the chip that limits the frequency of operation though, these should operate at much lower frequencies if an appropriate tuned circuit is attached. So, I will look at these chips in detail later. I was attracted to the Temic wwvb/dcf77 receiver chips because they draw 30 microamps...so, a receiver that draws 4 microamps is indeed low power and is very promising. Regards, A In any case, Temic was bought out by Atmel. I believe Atmel called this chip T4224 but when looking for it on their web site it ain't there. |
Hello Albert,
I was attracted to the Temic wwvb/dcf77 receiver chips because they draw 30 microamps...so, a receiver that draws 4 microamps is indeed low power and is very promising. AFAIK many "atomic clocks" listen to WWVB briefly and then turn off the receiver again. With a very low on/off duty cycle the power consumption of the receiver wouldn't matter so much. Regards, Joerg http://www.analogconsultants.com |
two crystals. These alone can cost more
than a whole clock. Of the longwave radio frequencies used for time standards, 40kHz (JJY, Japan), 77.5kHz (DCF, Germany) and 60 kHz (WWVB and MSF) crystals are off-the-shelf items in the Digikey catalog at less than a dollar each. I'm guessing their easy availability is because they are commonly used in real receivers. I've always noted with some curiosity that 77.503kHz, 60.002kHz, and 60.005kHz are off-the-shelf crystals too... used in a direct conversion receiver for DCF/WWV to 3Hz, 2Hz, and 5Hz carrier-detect frequencies maybe? Tim. |
I just noticed the availability of these crystals as I was thinking
about using a crystal in the front end to protect the receiver from adjacent frequency qrm. Not sure if this can be done unless one has a chip specially designed to take crystals (such as the Temic U4224B). Regarding the off frequency crystals.... It might be possible that these are rejects that didn't quite make the 60.000 kilohertx spec? Thanks, A Of the longwave radio frequencies used for time standards, 40kHz (JJY, Japan), 77.5kHz (DCF, Germany) and 60 kHz (WWVB and MSF) crystals are off-the-shelf items in the Digikey catalog at less than a dollar each. I'm guessing their easy availability is because they are commonly used in real receivers. I've always noted with some curiosity that 77.503kHz, 60.002kHz, and 60.005kHz are off-the-shelf crystals too... used in a direct conversion receiver for DCF/WWV to 3Hz, 2Hz, and 5Hz carrier-detect frequencies maybe? |
"Tim Shoppa" wrote in message
oups.com... Of the longwave radio frequencies used for time standards, 40kHz (JJY, Japan), 77.5kHz (DCF, Germany) and 60 kHz (WWVB and MSF) crystals are off-the-shelf items in the Digikey catalog at less than a dollar each. Really...! Hmm... perhaps time to re-visit the "WWVB receiver using op-amps and a small microcontroller" ida? One of the regular contributors to Circuit Cellar Ink tried it a while back (4 years?), but wasn't successful. A successful project would be worth a write-up in some hobbyist magazine (of what's left... Nuts & Volts seems to be about it in the US...) Anyone know which time service folks in Oz or the Kiwis use? ---Joel Kolstad |
Joel Kolstad wrote:
Really...! Hmm... perhaps time to re-visit the "WWVB receiver using op-amps and a small microcontroller" ida? One of the regular contributors to Circuit Cellar Ink tried it a while back (4 years?), but wasn't successful. A successful project would be worth a write-up in some hobbyist magazine (of what's left... Nuts & Volts seems to be about it in the US...) ---Joel Kolstad Take a look at Jim Thompson's early design. He's an IC designer who hangs out on the sci.electronics.* newsgroups. http://www.analog-innovations.com/SE...matic+Data.pdf -- Former professional electron wrangler. Michael A. Terrell Central Florida |
"Michael A. Terrell" wrote in message
... Take a look at Jim Thompson's early design. He's an IC designer who hangs out on the sci.electronics.* newsgroups. Yes, I've seen Jim's design before; it's quite impressive for 1974! For a contemporary design, the idea is that you could get by with far fewer parts (if not fewer transistors -- they're just buried in the ICs!). ---Joel |
On Tue, 5 Apr 2005 11:57:38 -0700, "Joel Kolstad"
wrote: "Michael A. Terrell" wrote in message ... Take a look at Jim Thompson's early design. He's an IC designer who hangs out on the sci.electronics.* newsgroups. Yes, I've seen Jim's design before; it's quite impressive for 1974! For a contemporary design, the idea is that you could get by with far fewer parts (if not fewer transistors -- they're just buried in the ICs!). ---Joel Particularly considering it was done BC (Before CAD :) Maybe I should try it again, using off-the-shelf components ?? ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | | http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
Jim Thompson wrote:
On Tue, 5 Apr 2005 11:57:38 -0700, "Joel Kolstad" wrote: "Michael A. Terrell" wrote in message ... Take a look at Jim Thompson's early design. He's an IC designer who hangs out on the sci.electronics.* newsgroups. Yes, I've seen Jim's design before; it's quite impressive for 1974! For a contemporary design, the idea is that you could get by with far fewer parts (if not fewer transistors -- they're just buried in the ICs!). ---Joel Particularly considering it was done BC (Before CAD :) Maybe I should try it again, using off-the-shelf components ?? ...Jim Thompson A "Before and after"? -- Former professional electron wrangler. Michael A. Terrell Central Florida |
Hello Jim,
Particularly considering it was done BC (Before CAD :) Maybe I should try it again, using off-the-shelf components ?? To be fair you'd have to do it with components that were available at reasonable prices in that era. My 2nd DCF receiver was built with several AF126 germanium transistors. On the first one I cheated by using opamps and somehow that didn't feel right back then. Except for the fact that one receiver drove a Nixie display I never built one with tubes. Now wouldn't that be something? Regards, Joerg http://www.analogconsultants.com |
Hello Tim,
Of the longwave radio frequencies used for time standards, 40kHz (JJY, Japan), 77.5kHz (DCF, Germany) and 60 kHz (WWVB and MSF) crystals are off-the-shelf items in the Digikey catalog at less than a dollar each. I'm guessing their easy availability is because they are commonly used in real receivers. Yes, but if these crystals are the only thing you'd have to buy right now that would easily become $10 with S&H. Or about half of what an atomic clock is at the discounters and there the price includes a huge display along with the receiver parts. I've always noted with some curiosity that 77.503kHz, 60.002kHz, and 60.005kHz are off-the-shelf crystals too... used in a direct conversion receiver for DCF/WWV to 3Hz, 2Hz, and 5Hz carrier-detect frequencies maybe? Strange. Maybe another resonance mode? Regards, Joerg http://www.analogconsultants.com |
Joerg wrote:
I've always noted with some curiosity that 77.503kHz, 60.002kHz, and 60.005kHz are off-the-shelf crystals too... used in a direct conversion receiver for DCF/WWV to 3Hz, 2Hz, and 5Hz carrier-detect frequencies maybe? Strange. Maybe another resonance mode? Regards, Joerg Maybe use them with the 60.000 KHz crystals to build a very narrow crystal filter? -- Former professional electron wrangler. Michael A. Terrell Central Florida |
Hello Michael,
Maybe use them with the 60.000 KHz crystals to build a very narrow crystal filter? Maybe but most WWVB receivers are more crude. They aren't concerned about shape factors and stuff, all they want is enough selectivity to make sure the things sync at night even if in California or Arizona. So there is usally one crystal as a filter, or two in series for the better ones. Regards, Joerg http://www.analogconsultants.com |
On Tue, 05 Apr 2005 21:56:31 +0000, Joerg wrote:
Hello Jim, Particularly considering it was done BC (Before CAD :) Maybe I should try it again, using off-the-shelf components ?? To be fair you'd have to do it with components that were available at reasonable prices in that era. My 2nd DCF receiver was built with several AF126 germanium transistors. On the first one I cheated by using opamps and somehow that didn't feel right back then. Except for the fact that one receiver drove a Nixie display I never built one with tubes. Now wouldn't that be something? Yabbut, it'd be a little cumbersome for a wall clock. ;-) Cheers! Rich |
Or about half of what an atomic clock is at the discounters
and there the price includes a huge display along with the receiver parts. Oh, I'm all for cannibalizing the commercial clocks, what with their pretuned ferrite loops, 60kHz receiver and demodulator, as a cost-and-time-effective method. But if someone did want to roll their own... I have custom ordered tuning-fork style crystals down to 12kHz, and they were way more than the mass-produced $1 jobbies! I think $30-$50 each in onesies. $1 is really cheap in comparison. Tim. |
Hello Rich,
Except for the fact that one receiver drove a Nixie display I never built one with tubes. Now wouldn't that be something? Yabbut, it'd be a little cumbersome for a wall clock. ;-) In the shape of a mantle clock it would work. Open chassis, of course, so the discerning visitor can admire. With nixies it would look really cool. Regards, Joerg http://www.analogconsultants.com |
Hello Tim,
Oh, I'm all for cannibalizing the commercial clocks, what with their pretuned ferrite loops, 60kHz receiver and demodulator, as a cost-and-time-effective method. But if someone did want to roll their own... In that case I'd probably try to do it with a PLL stabilized Q-multiplier instead of a crystal filter. Should work just fine at 60kHz. Or a conversion scheme that puts the IF in the low kHz range where it can be done with active or switched capacitor filters. Still have to stabilize the oscillator though. Just as a proof of concept... I have custom ordered tuning-fork style crystals down to 12kHz, and they were way more than the mass-produced $1 jobbies! I think $30-$50 each in onesies. $1 is really cheap in comparison. True, $1 is cheap. Custom crystals are less and less popular. Some of the companies I used way back when are no longer there or aren't doing it anymore unless you buy thousands. Regards, Joerg http://www.analogconsultants.com |
I've always noted with some curiosity that 77.503kHz,
60.002kHz, and 60.005kHz are off-the-shelf crystals too... used in a direct conversion receiver for DCF/WWV to 3Hz, 2Hz, and 5Hz carrier-detect frequencies maybe? Strange. Maybe another resonance mode? I'd guess the specified frequency is parallel resonance with the specified load capacitance. I have some Digi-Key SE3320-ND 60 Khz xctls (C-2 60.000KC-P). My best try at measuring the series resonant frequency shows 59998 Hz. Perhaps the 60.002 Khz ones are series resonant at 60000 Hz. I don't have any of those to measure. |
My appologies for the late reply but what is a "PLL stabilized
Q-multiplier"? |
From: "mike742" on Sun,Apr 17 2005 11:09 pm
I've always noted with some curiosity that 77.503kHz, 60.002kHz, and 60.005kHz are off-the-shelf crystals too... used in a direct conversion receiver for DCF/WWV to 3Hz, 2Hz, and 5Hz carrier-detect frequencies maybe? Strange. Maybe another resonance mode? I'd guess the specified frequency is parallel resonance with the specified load capacitance. I have some Digi-Key SE3320-ND 60 Khz xctls (C-2 60.000KC-P). My best try at measuring the series resonant frequency shows 59998 Hz. Perhaps the 60.002 Khz ones are series resonant at 60000 Hz. I don't have any of those to measure. To help us out, it would be best if you describe your method of testing the resonance frequencies and the accuracy of your frequency meter/counter. A -2 Hz "error" in frequency is about 33 PPM (Parts Per Million) or 0.0033 %. That seems to be within manufacturer's stated tolerance. For what it's worth, the spectral occupancy needed by the WWVB signal is roughly 5 Hz. That is good enough to demodulate the AM of WWVB and still preserve the (relative) sharpness of the digital amplitude transitions for purposes of obtaining the correct time of day. Modulation on WWVB is roughly 30% AM at 1 second periodicity. In my TRF receiver for 60 KHz, the carrier is extracted by amplifying the filtered signal and applying it to an over-driven MC1350P which acts as a limiter. Outside of the (relatively) broad selectivity of the tuned loop (Q roughly 45) and an interstage L-C tuned coupling, the final filter is simply two ECS crystals in series with a small capacitor to ground at the series connection point. The capacitor value was arrived at by "cut and try" substitution, much quicker than trying to calculate everything after an elaborate crystal measurement exercise. :-) The final selectivity is narrow enough to eliminate most of the LF hash around the spectrum, especially the 4th harmonics of the TV set horizontal sweep frequency. That should work equally well on non- limiting demodulation to get the time-of-day data. [without the DSP supplied by the microcontrollers in the radio clocks...we have two commercial units in the house for that] Measuring the exact crystal resonance frequency is NOT a simple exercise at 60 KHz. I would suggest looking closer at the Digi-Key links for technical data direct from the manufacturer. Those are found on the Digi-Key final part-number page just below the electronic catalog page PDF link. Manufacturer's data yields the parallel capacitance, maximum series resonance crystal equivalent resistance, and either the equivalent series inductance or the equivalent series capacitance. Digi-Key is excellent in their links to manufacturer's data in my estimation. |
I have some Digi-Key SE3320-ND 60 Khz xctls (C-2 60.000KC-P).
My best try at measuring the series resonant frequency shows 59998 Hz. Perhaps the 60.002 Khz ones are series resonant at 60000 Hz. I don't have any of those to measure. To help us out, it would be best if you describe your method of testing the resonance frequencies and the accuracy of your frequency meter/counter. .... Measuring the exact crystal resonance frequency is NOT a simple exercise at 60 KHz. I would suggest looking closer at the Digi-Key links for technical data direct from the manufacturer. Those are found on the Digi-Key final part-number page just below the electronic catalog page PDF link. Manufacturer's data yields the parallel capacitance, maximum series resonance crystal equivalent resistance, and either the equivalent series inductance or the equivalent series capacitance. Digi-Key is excellent in their links to manufacturer's data in my estimation. A -2 Hz "error" in frequency is about 33 PPM (Parts Per Million) or 0.0033 %. That seems to be within manufacturer's stated tolerance. I see what you're asking. The Digi-Key pages says 100 ppm (+/- 6 Hz @ 60 Khz). The Epson web page says they are photolithography-finished and at least one Epson data sheet says the standard frequency tolerance is 20 ppm. Possibly they have no problem hitting 20 ppm and the actual tolerance is much better than that (but not over temperature). 20 ppm is still 1.2 Hz wide and the resonance probably is sharper than that (Q 50K?). This measuring project started when I tried to use the Epson crystal data to calculate what the series resonant frequency would be of the 60 Khz parallel specified crystals. After much mucking around with various numbers I decided to measure it. And you're right, I've been ignoring calibration. Here's how I'm measuring the resonance: I have a homebrew LC VCO running at 6 Mhz. It's full frequency range is about 5.99180 to 6.0053 Mhz. This is divided by 100 (two 74LS90's) and then low pass filtered resulting in a sine wave around 60 Khz. The signal level is attenuated via 10k/1k resistors and then fed through the crystal with a 10k load on the other side. There's some additional loading from the x100 gain amplifier and then into a scope. The circuit around the xctl looks like: .1 10k from-e-follower-lowpass--||----/\/\/\/\/----+---| xctl |----+--- to x100 amp 1k 10k gnd gnd I can see a noise widened trace on the scope plus some switching spikes/artifacts. As I tune the VCO, the noise trace is flat except at one specific frequency, which is about 1 Hz at most wide where the noise band becomes a sine wave. I'm measuring the frequency of the 6 Mhz VCO with a Ramsey C-125 frequency counter. It's a standard ICM7216D counter with a cheap 10 Mhz crystal as the time base. It's uncalibrated (other than the factory, not sure of the date, possibly in the 70s?). Ok, how to calibrate the frequency counter? And how stable is the frequency counter? I'm living in a cloud of RF noise, plus computers. In addition the frequency counter is a real RF noise generator too (multiplexed LEDs in addition to the counting circuitry). By moving the counter and short wave radio to a different room I managed to hear the 2nd harmonic of a 5 Mhz crystal oscillator on 10 Mhz with WWV. It sounded like the beat frequency was lower in frequency than the 100 Hz WWV modulation pulses. So an upper bound of +/- 100 Hz at 10 Mhz would put the upper bound on the frequency counter of 10 ppm. I'm not really happy with this calibration, I'll have to see what I can do to improve it. |
I'm not really happy with this calibration,
I'll have to see what I can do to improve it. Zero-beat to WWV is hard to do better than 50Hz by ear. Mechanical aids will get you a little better but then at the few Hz level you hit variations in carrier due to ionospheric variation. For a few hundred $, HP Z3801A's are available on the surplus market. They're a 10MHz OCXO locked to GPS. Short term Allan variation is 10^-12 or better over 1-100 seconds. Many lab counters and a lot of ham radio frequency counters will happily accept the 10MHz reference that the Z3801A makes. Other telecom-related GPS-locked OCXO's/rubidium oscillators are available on the surplus market too, some make telco-related reference frequencies like 1.544MHz or 19.6608MHz which can be used to calibrate on. Tim. |
I read in sci.electronics.design that Tim Shoppa
wrote (in .com) about 'wwvb receiver chip needed', on Tue, 26 Apr 2005: Zero-beat to WWV is hard to do better than 50Hz by ear. Have you tried a Lissajou display? -- Regards, John Woodgate, OOO - Own Opinions Only. There are two sides to every question, except 'What is a Moebius strip?' http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |
"John Woodgate" wrote in message ... I read in sci.electronics.design that Tim Shoppa wrote (in .com) about 'wwvb receiver chip needed', on Tue, 26 Apr 2005: Zero-beat to WWV is hard to do better than 50Hz by ear. Have you tried a Lissajou display? -- Or use the S-meter to see very low freq beats. |
mike742 wrote: I've always noted with some curiosity that 77.503kHz, 60.002kHz, and 60.005kHz are off-the-shelf crystals too... used in a direct conversion receiver for DCF/WWV to 3Hz, 2Hz, and 5Hz carrier-detect frequencies maybe? Strange. Maybe another resonance mode? I'd guess the specified frequency is parallel resonance with the specified load capacitance. I have some Digi-Key SE3320-ND 60 Khz xctls (C-2 60.000KC-P). My best try at measuring the series resonant frequency shows 59998 Hz. Perhaps the 60.002 Khz ones are series resonant at 60000 Hz. I don't have any of those to measure. Here are some measurement of a few Epson Type 2 60 kHz crystals I made recently: Fs BW Fp 60001.6 4.6 60009.9 60001.2 4.6 60009.7 60002.2 5.6 60010.6 60001.1 4.4 60009.5 The test setup is shown below. The input signal was produced by my homebrew function generator implemented with an AD9833. The clock for the 9833 is an 10 MHz SG-615B which has a specified frequency stability of 100 PPM. |Vcc | | 20.0k | Vi 0.1++ |-+ 2N5457 -/\/\-+--||-||--+-| | ++ | |-+-- Vo \ \ | / 1M / \ 1.0k \ \ /1k | | \ | | | +---------+----+ | V |
"Watson A.Name - "Watt Sun, the Dark Remover"" wrote
in message ... Or use the S-meter to see very low freq beats. Check out the latest Atlanticon proceedings, or the upcoming issue of the Homebrewer for a circuit to allow you to see zero beat to within a fraction of a Hz. ... |
["Followup-To:" header set to rec.radio.amateur.homebrew.]
On Wed, 27 Apr 2005 06:01:02 -0700, Watson A.Name wrote: "John Woodgate" wrote in message ... I read in sci.electronics.design that Tim Shoppa wrote (in .com) about 'wwvb receiver chip needed', on Tue, 26 Apr 2005: Zero-beat to WWV is hard to do better than 50Hz by ear. Have you tried a Lissajou display? Or use the S-meter to see very low freq beats. S-Meter! On 'modern' gear?? All they give you is a bank of eye candy in the form of leds. But, yes -- I've used Real S-Meters to get Real Damn Close to zero best in days past. 73 Jonesy -- | Marvin L Jones | jonz | W3DHJ | linux | Gunnison, Colorado | @ | Jonesy | OS/2 __ | 7,703' -- 2,345m | config.com | DM68mn SK |
On 27 Apr 2005 16:04:33 GMT, Allodoxaphobia wrote:
But, yes -- I've used Real S-Meters to get Real Damn Close to zero best in days past. Well, ... "best beat" works, too. Jonesy |
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