in need of a transmitter (newbie)

[p-71]

Hi I really like this forum

I need a transmitter that puts out 8khz@50% duty cycle for a time of 30ms

I have two different websites that say that I need the one above then the other one says that I need this one
8130hz
I would probley use a 555 timer
Circuit digram would be better


Thanks for any help
p-71

 

[Phasor]

A 555 (or any other RC oscillator) is probably not accurate or stable enough for a transmitter.

Consider using a crystal-based oscillator.

 

[Russlk]

The 555 cannot do 50% duty cycle, if you double the frequency and divide by 2 with a flip-flop, that will be an accurate 50% duty cycle. What do you mean by transmitter? Do you mean oscillator? How accurate does the 30 mS have to be? For an accurate 240 cycles, use a counter otherwise another 555 would work.

 

[Nigel Goodwin]

Hi I really like this forum

I need a transmitter that puts out 8khz@50% duty cycle for a time of 30ms

I have two different websites that say that I need the one above then the other one says that I need this one
8130hz
I would probley use a 555 timer
Circuit digram would be better


Thanks for any help
p-71

If you mean a tone burst generator, they usually use two 555's (or a 556), or even just a CMOS logic gate - I'm sure if you look on amateur radio sites you'll find loads of examples - although your frequencies sound far higher than used to be used.