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2-Tone Test for Positive Peaks




 
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Author Topic: 2-Tone Test for Positive Peaks  (Read 20593 times)
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W2PFY
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« Reply #25 on: January 14, 2015, 02:54:50 PM »

Here is the two tone signal as per specs but I think the user will have to adjust the level at the user site. I hope its ok as I am not used to doing anything like this Grin Grin

* TWO TONE SIGNAL.mp3 (366.04 KB - downloaded 393 times.)

* Screen Shot 01-14-15 at 02.56 PM.JPG (876.22 KB, 1617x1217 - viewed 853 times.)
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AB2EZ
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"Season's Greetings" looks okay to me...


« Reply #26 on: January 14, 2015, 02:55:29 PM »

Attached is a 100 second MPEG3 file (mono)

It consists of sin(2pi 500.01t) + sin(2pi 1000t)

My audio generator application allows me to generate two sine wave tones, but it doesn't allow me to adjust their relative phase.

So... I set one of the frequencies at 500.01 Hz instead of 500Hz. Over the 100 second duration of this recording, the two tones slowly shift their relative phase over 2pi radians.

If you look at the whole 100 second waveform on a scope, with the sweep set to 0.2ms or 0.5ms per division, and watching for 100 seconds, you will see the effect of the phase shift on the sum of the two sine waves.

For a good portion of this 100 second waveform (at least 5 seconds), the phase relationship is such that what you have is basically sin(2pi 500t + pi/4) + sin(2pi 1000t) ... which has the same shape as cos(2pi 500t) + cos(2pi 1000t)... which is the desired test waveform shape.


Stu

* 2-tone.mp3 (1953.7 KB - downloaded 408 times.)
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Stewart ("Stu") Personick. Pictured: (from The New Yorker) "Season's Greetings" looks OK to me. Let's run it by the legal department
W2PFY
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« Reply #27 on: January 14, 2015, 03:07:03 PM »

Maybe there is something wrong with my tones? i can hear both tones but not the sum of the two?
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AB2EZ
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"Season's Greetings" looks okay to me...


« Reply #28 on: January 14, 2015, 03:25:25 PM »

Terry

Your file has one tone on the left channel and the other tone on the right channel.

When I combine the two outputs of my sound card with a Y-adaptor... the result is exactly what is needed. The phase relationship of the two sine waves is correct for the purpose of producing the desired test tone.

Stu

Maybe there is something wrong with my tones? i can hear both tones but not the sum of the two?
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Stewart ("Stu") Personick. Pictured: (from The New Yorker) "Season's Greetings" looks OK to me. Let's run it by the legal department
W2PFY
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« Reply #29 on: January 14, 2015, 03:31:29 PM »

Stu, with this setup, I cannot combine them. Can you post the combined tones from my mp3?

tnx Terry
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WB4AIO
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« Reply #30 on: January 14, 2015, 03:35:13 PM »

Stu, with this setup, I cannot combine them. Can you post the combined tones from my mp3?

tnx Terry

Here's a mono mixdown version.

Thanks guys,

Kevin, WB4AIO.

* TWO TONE AM pos peak mono SIGNAL.mp3 (123.36 KB - downloaded 399 times.)
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ka1bwo
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« Reply #31 on: January 15, 2015, 08:39:29 PM »

Here's a look at the waveform. The center horizontal graticule line is zero volts.
Joe







Stu, with this setup, I cannot combine them. Can you post the combined tones from my mp3?

tnx Terry

Here's a mono mixdown version.

Thanks guys,

Kevin, WB4AIO.


* waveform.JPG (2352.2 KB, 3264x2448 - viewed 772 times.)
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WD5JKO
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« Reply #32 on: January 15, 2015, 10:02:18 PM »


     
Some time back I was doing two tone tests on my Gonset G-76. The frequencies were 700hz and 1900hz.

I include a scope image of the test. Getting a good scope trigger was impossible until I changed the variable time base.

Jim
Wd5JKO


* G76_2_Tone.jpg (51.58 KB, 640x480 - viewed 807 times.)
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