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Topic: Your latest purchase (Read 124099 times) previous topic - next topic

CrossRoads

Great! So rip that into a joint-stereo at 256K sampling rate and post it for us 8)
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

justjed


Great! So rip that into a joint-stereo at 256K sampling rate and post it for us 8)


If you mean Dominique, well, it's a monaural recording, and my Dual is out of service anyway. But I'm sure you can find it on YouTube.  :smiley-eek:
... it is poor civic hygiene to install technologies that could someday
facilitate a police state. -- Bruce Schneier

cr0sh

Yea, I have kind of a love/hate relationship with Goodwill stores. About 15 years ago I spend a lot of time searching for those high quality brands and models of vintage 70s hi-fi stereo equipment and LP records.


I guess maybe the Goodwills here in the Phoenix area are just better (now if only we could fix our daft state legislature and county sheriff, things would be perfect).

Rarely do I go into a Goodwill and leave empty handed (to the chagrin of my wife); the find of the X-10 cameras was unexpected - they were all in a plastic tub they were shelf-stocking from. I saw them, pulled out one bag after another (each bagged separately), and decided on the whole lot. Some other guy came up to me and handed me some more (which was weird - he was a customer, too).

I've found strange computers (media-box type machines, and once a small embedded PC board custom-made BSD firewall), as well as built my Playstation 2 system from Goodwill castoffs (which I hardly play!). Recently I got a complete GameCube system set up (our Goodwills seem to be great places for older gaming systems).

Tons of great toy RC cars to be had (I once found an MGA Tarantula for $25.00); I also find many Robosapians and other Wowee 'bots. On occasion you can even run across some good vintage 70's audio gear (I found a real nice 1970's AKAI turntable for my component stereo at Goodwill about a year or so ago); I've recently seen a few 1/4" reel-to-reel players that were in decent shape (I already have my dad's, and don't need another).
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

CrossRoads

@justjed, I was actually Sally Fields, The Flying Nun, but Dominique is much better. I think I may actually have copy already, have to check my hard drive o'music that I udpate my Neuros Audio MP3 player with occasionally.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Nick Gammon

Second-hand Rubidium Frequency Standard:



Cost: $80 on eBay.

Measured:



As described by Dave Jones:

http://www.eevblog.com/2012/01/14/eevblog-235-rubidium-frequency-standard/
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

Nick Gammon

Oh yes, and this came in the parcel, strangely enough:



A small bear and a 7805 voltage regulator.
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

mmcp42

your frequency meter looks pretty accurate too
so how do you tell if the frequency meter or the frequency standard is off?
or do you assume the standard is good and adjust the meter?
there are only 10 types of people
them that understands binary
and them that doesn't

retrolefty


your frequency meter looks pretty accurate too
so how do you tell if the frequency meter or the frequency standard is off?
or do you assume the standard is good and adjust the meter?


Yes, any calibration/validation procedure is based on some 'standard' or 'reference' you have avalible to you. The better the standard the more accurate your procedure will be. The old rule of thumb is that your standards or references need to be 10 times the accuracy specification of the thing you are attempting to calibrate.

Of all the electrical measurements possible, frequency is the one that has the best standards and accuracy avalible. That Rubidium Frequency Standard requires no adjustment, it's based on a fixed property of the wavelength of Rubidium, thus making it a very desirable frequency standard.

Lefty

focalist


Oh yes, and this came in the parcel, strangely enough:



A small bear and a 7805 voltage regulator.


Offering alternatives on ways to cope with unregulated power?
When the testing is complete there will be... cake.

Nick Gammon


your frequency meter looks pretty accurate too
so how do you tell if the frequency meter or the frequency standard is off?


Well this was interesting. I put the output from my signal generator (also nominally 10 MHz if required) into the same counter, and it gave the same results (10000.046). That's nice, I thought, my signal generator is correct. But putting both signals into the scope it was obvious they weren't the same frequency at all. In fact, compared to the Rubidium standard the signal generator kept changing (speeding up, I think), no doubt as it warmed up.
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

BenF

Quote
That's nice, I thought, my signal generator is correct ...

I was impressed by your frequency meter with three decimals precision. Putting it to test and finding it is less precise than expected kind of ruins your day.   :smiley-slim:

The saying, "A man with one clock knows what time it is. A man with two clocks is never sure." seems to apply here as well.


Nick Gammon

Well that clearly demonstrate the difference between precision and accuracy.
Please post technical questions on the forum, not by personal message. Thanks!

More info:
http://www.gammon.com.au/electronics

retrolefty


Well that clearly demonstrate the difference between precision and accuracy.


I spent a career with instrumentation. Accuracy is one of the most misunderstood, misused, and abused word in the world of electronics. Never trust a salesman or his spec sheets. Never accept an accuracy figure or specification without knowing and asking a whole lot of questions about how they are arriving at their specification and under what conditions.

It's a very interesting field, measurements and standards, but far from as simple as one might first think.

Lefty

winner10920

I got a 1m blue led strip for 1$ free shipping off ebay, buyitnow price 10$ XD
Waiting g for the day I get that 5m rgb strip with ir control for 1$ instead of 20

cr0sh


Oh yes, and this came in the parcel, strangely enough:



A small bear and a 7805 voltage regulator.


Was it a chinese supplier? They almost always seem to throw in wacky "extras"... ;)
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

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