The Beast

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Re: The Beast

Postby Steve Anderson » Sun Aug 01, 2021 1:26 pm

...quoting myself..."The oscillator I was thinking of is in the Off-Topic section, "A Useful General Purpose Oscillator.". It perhaps could do with some simplification...skip ahead to the last few posts..."

I have already done some simplification a while back, I just haven't posted it yet. I'll review, maybe simplify further and update...

Steve A.

However, it's already simpler than the 'kit' version in this thread, it only uses a 14-pin micro instead of 40-pins, generates sine, triangle and square (logic) signals, and covers from below 1Hz up to 12.5MHz. But it doesn't have the display and isn't stand-alone, it requires (usually) a PC to control it. As ever, a compromise. The D-A is also 10-bit rather than 8.

It could be made stand-alone, but with wanting to automate frequently mundane tasks it would need some form of programmability, the old PC comes to the rescue again! Mundane tasks...frequency response of filters done manually is somewhat of a pain. It's much nicer to push a 'GO' button and watch the results...though it would need a companion unit to take the measurement(s) and report the findings...though the two could be built as a single instrument.

It all depends on your requirements, for just NBTV it's probably overkill, but I have other uses for it.

I did post a photo of the prototype oscillator part on Sep 22, 2020, but here it is again...it's not quite as complex as the circuit may seem...it also includes the regulator...where has the past year (almost) gone?

Anyway, again I'm digressing...any update on this will be in the correct 'Off-Topic' thread mentioned above...but, while I'm here, I might point out that a 74HC540 is fitted as a TTL output chip, I'll be replacing it with a 74AC540 for faster rising/falling edges on the TTL/logic outputs.

AD9833 DCO 1.jpg
AD9833 DCO 1.jpg (162.97 KiB) Viewed 341 times
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Re: The Beast

Postby Harry Dalek » Sun Aug 01, 2021 9:03 pm

Steve Anderson wrote:...quoting myself..."The oscillator I was thinking of is in the Off-Topic section, "A Useful General Purpose Oscillator.". It perhaps could do with some simplification...skip ahead to the last few posts..."

I have already done some simplification a while back, I just haven't posted it yet. I'll review, maybe simplify further and update...

Steve A.

However, it's already simpler than the 'kit' version in this thread, it only uses a 14-pin micro instead of 40-pins, generates sine, triangle and square (logic) signals, and covers from below 1Hz up to 12.5MHz. But it doesn't have the display and isn't stand-alone, it requires (usually) a PC to control it. As ever, a compromise. The D-A is also 10-bit rather than 8.

It could be made stand-alone, but with wanting to automate frequently mundane tasks it would need some form of programmability, the old PC comes to the rescue again! Mundane tasks...frequency response of filters done manually is somewhat of a pain. It's much nicer to push a 'GO' button and watch the results...though it would need a companion unit to take the measurement(s) and report the findings...though the two could be built as a single instrument.

It all depends on your requirements, for just NBTV it's probably overkill, but I have other uses for it.

I did post a photo of the prototype oscillator part on Sep 22, 2020, but here it is again...it's not quite as complex as the circuit may seem...it also includes the regulator...where has the past year (almost) gone?

Anyway, again I'm digressing...any update on this will be in the correct 'Off-Topic' thread mentioned above...but, while I'm here, I might point out that a 74HC540 is fitted as a TTL output chip, I'll be replacing it with a 74AC540 for faster rising/falling edges on the TTL/logic outputs.

AD9833 DCO 1.jpg


Are you going to test your Sound cards Steve more than likely already have i would think you have a bench signal generator ? ,by rights any old sound card would do 20 khz bandwidth if its set at 48 khz in your cards sounds windows sound setting .
I was surprised looking and adjusting top settings on my new laptops both only did 48khz 24 bit where as my older one i used for testing the Beast seems to go 96khz .but again if its doing that or not is another matter thus all the oscillator talk going on here .
I ended up buying a USB DAC sound card dongle ,as these new lap tops don't have mic inputs come in useful but would like to also see if there's an improvement with a little more bandwidth on the output ,the one i am getting is 192khz 24 bit which would be half that in bandwidth 96khz another one for a test ,if i see it works up around that i will look into what else is out there .
I know you want the oscillator test to go from the hardware oscillator to sound card input and see what comes out it on a scope but can only hope the line in or mic in side of the sound card is set the same who knows the data on your sound device might be slower .
I like the idea of a PC made sinewave oscillator that could work past 20khz must be possible to produce it software wise ,it would be good just to test the output side of the card and also then do the input with a hardware oscillator and see if its the same result ,but yet to find any thing that works past 20khz .
Yes the oscillator you are working on is a bit smaller than what you started with little did i know these things would be needed for this ,i suppose when you have a need you go looking .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Beast

Postby Steve Anderson » Mon Aug 02, 2021 11:44 am

Harry Dalek wrote:...Are you going to test your Sound cards Steve more than likely already have i would think you have a bench signal generator ?

Actually no. In fact the PC I'll be using this with doesn't even have a 'sound card'. For the machine(s) that do I'll not be using them anyway. I do have a small external one I mentioned a week or two ago if I simply want to record/playback audio. (The behringer UFO202). But not for this.

I do have a bench generator but it's fading fast, it should have been retired over a decade ago, but it was quite good in its day (30-odd years ago). This should replace it, all that's needed is sine and square (logic) signals. I can't recall ever needing the sawtooth/triangle outputs. So it's simpler from a users perspective, more accurate and stable, and programmable. It doesn't need to be ultra-low distortion and things like that, I'm not testing Hi-Fi amplifiers and the like.

It may be complimented by a measuring unit (or merged into one instrument) to record test results. One of the more tedious tasks is frequency response testing. Automating it means I can go and pour a beer while the machine does all the boring stuff for me...can't waste valuable time can we?

Steve A.

If you need a 'proper' automated audio test system the Lindos LA100 is really useful, I used them for many years in broadcasting...not for the hobbyist though...

http://www.lindos.co.uk/la100
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Re: The Beast

Postby Harry Dalek » Mon Aug 02, 2021 9:11 pm

Steve Anderson wrote:Actually no. In fact the PC I'll be using this with doesn't even have a 'sound card'. For the machine(s) that do I'll not be using them anyway. I do have a small external one I mentioned a week or two ago if I simply want to record/playback audio. (The behringer UFO202). But not for this.


That's a nice little gadget ,a lot of these things about price is over the place but for these buyer should shop around seem mostly to be 30 dollars

I do have a bench generator but it's fading fast, it should have been retired over a decade ago, but it was quite good in its day (30-odd years ago). This should replace it, all that's needed is sine and square (logic) signals. I can't recall ever needing the sawtooth/triangle outputs. So it's simpler from a users perspective, more accurate and stable, and programmable. It doesn't need to be ultra-low distortion and things like that, I'm not testing Hi-Fi amplifiers and the like.


I could really only think of needing square or sinewaves as well ,being old is not that bad yours being around 1990 like yesterday ; )

It may be complimented by a measuring unit (or merged into one instrument) to record test results. One of the more tedious tasks is frequency response testing. Automating it means I can go and pour a beer while the machine does all the boring stuff for me...can't waste valuable time can we?

Steve A.

BTW has Audacity's has "Plot Spectrum" also has a tone generator touch over 20khz but i think it would go higher depending on your sound device there's no limit shown just a cut off when i think its all your card and output speculating seems like that ,think mine go's to 24 khz
WAC_96kHz_test_SpAn.png



If you need a 'proper' automated audio test system the Lindos LA100 is really useful, I used them for many years in broadcasting...not for the hobbyist though...

http://www.lindos.co.uk/la100


That would be nice i would just have to watch your reported results if you end up using one :wink:
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Beast

Postby Steve Anderson » Mon Aug 02, 2021 9:38 pm

Harry Dalek wrote:http://www.lindos.co.uk/la100
That would be nice i would just have to watch your reported results if you end up using one :wink:

They were (the Lindos LA1 and later the LA100) the main instruments of my work up until the mid-80s. Now I'm primarily out of audio broadcasting I have no requirement for them, I can't afford them anyway! And really not applicable to home audio or NBTV. Prior to the Lindos instruments it was a large clunky Ferrograph unit the size of a substantial industrial microwave oven (weighed the same and probably used as much power!). It resided on a trolley, you couldn't carry it around...I found this small image of it...two 19" 3RU units...(3RU=5.25" each high)...or approx. 133mm high each..

Steve A.

Ferrograph-RTS2-ATU-Audio-Generator-Millivoltmeter-Wow-Flutter-Distortion-meter.jpg
Ferrograph-RTS2-ATU-Audio-Generator-Millivoltmeter-Wow-Flutter-Distortion-meter.jpg (28.26 KiB) Viewed 309 times


A 'Rack Unit' is a standard measurement still used today for 19" Rack-mounted equipment. One RU = 1.75" or 44.5mm. Blame the UK Navy for this...same with the BNC connector, the "British Naval Connector". Available in 50, 75, & 93 Ohm versions...and they all happily fit each other, forget the impedance mis-match...

Any scope made in the last 40 years (apart from toys with binding posts) has a BNC input connector, in this case more suitable for the high input impedance of 1M for the usual scope input, with or without a x10 probe....or x100, x1000 for those dabbling in real HV stuff!

The BNC connector is a fully-screened and hi-RF coaxial connector, so far, for test equipment nothing much has replaced it it since the 40s...eighty years ago...SMA, OK, it great for 10GHz+, but it's too small for day-to-day test equipment manipulated by human hands...once in a while, OK...and usually used with brass 'rigid lines' rather than flexible cable...you need a small spanner (UK), wrench (US), shifter (Aus) to fit them...Thailand? Probably a hammer...
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Re: The Beast

Postby Harry Dalek » Sun Aug 08, 2021 7:45 pm

Nice Gear Steve !
BTW i Tested my 96Khz/24bit USB only problem it inverts the video so have to adjust this in the monitor to see results correctly .
In windows in the sound card setting i can only do 48 khz viewing the highest setting ,when this usb sound device is plugged in it can be set to over 100 khz which it does say it can do ,so there must be an improvement ,at only under 10 dollars.
recordings about the same but i was interested in outputting here .
About this item
[Superior Audio Performance] With the built-in advanced DAC of ultra-low distortion and noise, Cubilux USB external sound card reproduces clean, natural sound with all the depth and details. The full-scale output voltage is 1Vrms, powerful enough to drive a wide range of headphones - from earbuds and gaming headsets to more expensive studio-grade headphones.
[Support Hi-Res Audio Stream] Capable of decoding audio stream up to 192KHz/24-bit to give you the original and lossless listening experience. It can also record at 48KHz/24-bit
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 4780
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