What is my Automatic Distortion Meter for?

[Clyd3]

Hi, I've got this cool looking thing (not an alien) and i'm yet to determine it's use.

Though i've given it some google and wikipedia and everything, I'd love to know exactly what it is and what i can use it for. (I don't feel like throwing it away - cause it looks cool.)

Is this beautiful contraption for audio or for "In electronics, the decibel is often used to express power or amplitude ratios (gains), in preference to arithmetic ratios or percentages."

Here's a long description:

It's got two nice strong handles on the front (looks very professional)
It's got two meter needle things, one labled dB level and the other dB distortion.

It's then got 3 sets of buttons! (wow!)

under the dB level meter, it has a section of buttons called function, choose: 400Hz, 1000Hz "LEVEL" (whatever that is).
It's got a section called distortion under the dB distortion meter, including: 30% or -10dB, 10$ or -20 dB, 3% or -30 dB, 1% or -40dB, 0.3 or -50 and lastly a "CAL" button.
Then at the bottom it has the third set of 8 buttons, called "range" that range from 30V or 30cB to 0.01V and -40dB.

It has two banana screw terminal thingies for input and ground. Theres a line going from them to the third set or "range" buttons (suggesting you look in the range you're looking for).

And then a power light, and switch. It runs off 100V ac and has a fuse and a distortion, level 1 and level two adjusting screw things.

 

[Optikon]

Hi, I've got this cool looking thing (not an alien) and i'm yet to determine it's use.

Though i've given it some google and wikipedia and everything, I'd love to know exactly what it is and what i can use it for. (I don't feel like throwing it away - cause it looks cool.)

Is this beautiful contraption for audio or for "In electronics, the decibel is often used to express power or amplitude ratios (gains), in preference to arithmetic ratios or percentages."

Here's a long description:

It's got two nice strong handles on the front (looks very professional)
It's got two meter needle things, one labled dB level and the other dB distortion.

It's then got 3 sets of buttons! (wow!)

under the dB level meter, it has a section of buttons called function, choose: 400Hz, 1000Hz "LEVEL" (whatever that is).
It's got a section called distortion under the dB distortion meter, including: 30% or -10dB, 10$ or -20 dB, 3% or -30 dB, 1% or -40dB, 0.3 or -50 and lastly a "CAL" button.
Then at the bottom it has the third set of 8 buttons, called "range" that range from 30V or 30cB to 0.01V and -40dB.

It has two banana screw terminal thingies for input and ground. Theres a line going from them to the third set or "range" buttons (suggesting you look in the range you're looking for).

And then a power light, and switch. It runs off 100V ac and has a fuse and a distortion, level 1 and level two adjusting screw things.

Well, likely it is for measuring distortion? I presume THD? It very well may be out of calibration but might still be good for relative measurements. If it were me, I would keep it and learn how to use it (might come in handy one day) but then again, I keep alot of things I probably shouldn't.

 

[Clyd3]

well today was the day of unkeeping things, which comes almost every year. Need a flippin flatbed to cart some of this stuff away... Total Harmonic Distortion?
wikipediaing distortion gave the following sections:

Electronic signals
* 1.1 Amplitude distortion
* 1.2 Frequency distortion
* 1.3 Phase distortion
* 1.4 Group delay distortion

i wonder which one it is. Probably amplitude, cause of all the values in dB or V.

Total harmonic distortion - Wikipedia, the free encyclopedia

 

[Mikebits]

It has been awhile since I used one, but sounds like you may have a SINAD meter. Stands for signal to noise and distortion.

 

[Clyd3]

Ok, I can see how that could be useful. Mikebits, what were you using one for?

 

[Mikebits]

Like I said, it has been a long time since I used one, but back when I did, it was used for checking receiver sensitivity. I think you can also use them for other applications such as audio, but I don't know for sure. Here are a couple links about SINAD.
The last link shows how one might hook a sinad meter up.
Direct reading sinad meter - Patent 4068176
http://www.spsc.tugraz.at/courses/msp/msp/data/MT-003_SINAD.pdf
EIA SINAD Sensitivity Measurement, Method 2, page 28

 

[audioguru]

In "the good old days" an amplifier made with germanium transistors was difficult to make work properly because there were a few good transistors and many poor ones. Their spec's varied from one transistor to the next. A distortion analyser meter was used to pass good amplifiers and fail distorted ones.

Now opamps are so good that their distortion is almost nothing.
I designed an audio equalizer that used 4 opamps per channel. Thousands were made and tested for supply current, gain, EQ accuracy at 6 frequencies, very low harmonic distortion and very low noise. They all passed except one with a quad opamp installed backwards and one with a shorted capacitor. The harmonic distortion was only 0.003%. Many meters cannot measure distortion that low.