222 Stereo Encoder Modified

thanks for the diagram!! 

I sat down and played with a circuit for 38kHz crystals, that hopefully is simple enough and uses easily available part for most people. The 19kHz sinewave output after the RC filter will be bit more distorted than in the original circuit, because the 555 can't deliver a 50% duty cycle with this setup. I don't think it matter too much, but maybe Harry or someone else that has better knowledge than me can chime in.
This circuit is just a suggestion.

Runem wrote:If you live on the South American continent, i'm guessing you should be able to get 38.000 kHz crystals from the larger North American suppliers. If you can't, and you're still interested, I know a source of these in Sweden.  I can add a few of them to my next order and send you a couple, if you dare give me your address (via PM). 



PS.
No I am not an ID thieve, (e)mail spammer or anything like that, and I always delete personal information from my computer.

Thanks!! but i have no online payment!! im here in Asia Philippines!!

If you live on the South American continent, i'm guessing you should be able to get 38.000 kHz crystals from the larger North American suppliers. If you can't, and you're still interested, I know a source of these in Sweden.  I can add a few of them to my next order and send you a couple, if you dare give me your address (via PM). 



PS.
No I am not an ID thieve, (e)mail spammer or anything like that, and I always delete personal information from my computer.

thanks for the response! yes i know that this is not best, but i say how to make it good, i did not compare it to other because there are many good quality stereo coder on the net! so i can say is for that schematic on how to make it good and there is no problem encounter and not compare to other!

how about filtering? can you give me some sample?

thanks for the reply!! )

A free running oscillator is simply not stable enough to generate the pilot tone and the 38 KHz. for the multiplexer.
The specification for the 19 KHz pilot tone is + or - 0.5 Hz!

N.B: Although this stereo encoder will work, it certainly isn't the best design I have ever seen. Because of the lack of filtering after the multiplexer, harmonics of the 38 KHz will appear in the output signal.
Also the input signals are not filtered. The inputs should have a 'brick wall' filter with nothing passing above 15 KHz.

I was modified the Stereo Encoder by sir Harry!

here is harry's encoder http://www.sm0vpo.com/audio/stereo_enc.htm

because the crystal and some part of its component is hard to find, except when you buy online!! but i have no credit card to buy online!! so I was modified his diagram that's all parts maybe available in my location, but I'm not test this circuit in real! i want to make it perfect before i build this circuit! so i need a professional to analyze this diagram and modified if required, if this is good and there is no problem after the build!!

here is the Spectrum:


here is the modified diagram:


hoping anyone can analyze this diagram!!

thanks in advanced!!