Standard generator 1khz-1V

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FoMoCo

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Joined 2012
Project16 said:
Hello everyone!

I need to make a standard 1khz generator 1v to set up an amplifier and I found this simple scheme that interests me.

Crystal-controlled 1KHz generator - top electronics

The problem is that I do not know if this arrangement achieves these 1Volt or if it exceeds.
What do you think?
Maybe you have other scheme proposal!

Regards!
Click to expand...
It will exceed it. The output will be a square-wave that has a low of 0V and a high of 5V, if a 5V supply is used. This is the same as 5Vpp with a 2.5Vdc offset. Probably not what you want.
 
Mooly

Mooly

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KC2ZPK said:
Sorry to jump in here, but how would you ensure the 1v level?

Thanks
John
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That's a good question... and the answer is that you can't as such. That's because all players have different output levels. What we normally record as a test tone would be at the 0db level, a level that uses the full dynamic range available to us. When that disc is played back you see a voltage level that is unique to each player such as 2.1 volts 1.9 volts, maybe 1.4 volts on a portable etc.

Having said that its easy to record a tone of say 100 to 400hz (that falls within any DVM's frequency range) and then have an external adjustable buffer and set the level to 1.00 volts. Accuracy limited only by the DVM. Having done that, any frequency on the disc will be at that same level to the accuracy of the players DAC and filters... usually fractions of a db.
 
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KC2ZPK

Member
Joined 2013
Mooly said:
That's a good question... and the answer is that you can't as such. That's because all players have different output levels. What we normally record as a test tone would be at the 0db level, a level that uses the full dynamic range available to us. When that disc is played back you see a voltage level that is unique to each player such as 2.1 volts 1.9 volts, maybe 1.4 volts on a portable etc.

Having said that its easy to record a tone of say 100 to 400hz (that falls within any DVM's frequency range) and then have an external adjustable buffer and set the level to 1.00 volts. Accuracy limited only by the DVM. Having done that, any frequency on the disc will be at that same level to the accuracy of the players DAC and filters... usually fractions of a db.
Click to expand...

Ok, bear with me.... I am going to have some questions :)
I can use Audacity to generate any tone, 1kHZ for this example, 'normalize to 0db' then save that track to my MP3(or other). Now play this track and measure the output with a DVM? But it will be out of the headphone jack, which will be higher than 1v. Could you use an op-amp buffer to set this level? either higher or lower? Line out would probably be better? Can I assume the line outs usually do not have any equalization done to it, such as bass boost?

Thanks
 
E

Enzo

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Joined 2004
It is 1kHz, there is no bass to boost. If all you are doing is recording a 1kHz tone, then as long as it records it cleanly, it doesn't much matter what the rest of the audio range does. If your player makes the same volume every time, then it will play at the same level every time.
 
Mooly

Mooly

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Joined 2007
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KC2ZPK said:
Ok, bear with me.... I am going to have some questions :)
I can use Audacity to generate any tone, 1kHZ for this example, 'normalize to 0db' then save that track to my MP3(or other). Now play this track and measure the output with a DVM? But it will be out of the headphone jack, which will be higher than 1v. Could you use an op-amp buffer to set this level? either higher or lower? Line out would probably be better? Can I assume the line outs usually do not have any equalization done to it, such as bass boost?

Thanks
Click to expand...

For some reason I missed seeing your post today. Sorry about that...

So, unless you are using a portable player (because some have tone controls/eq/bass boost etc) then the line and headphone feeds have no equalisation as such. Whatever level you set to record at with Audacity will give the same playback level at any frequency you choose from around 5Hz to 20kHz.

A simple opamp buffer with a preset pot at the input is all that is needed. For 1 volt output the opamp would comfortably run on a single 9 volt supply. 2 volts rms is around 5.6 volts peak to peak, still do-able on a 9 volt supply with the right opamp. To get higher levels would need a higher supply voltage.
 
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