pulse generator

[legend killer]

Hi everyone,
I am planning to implement a circuit which could demonstrate the working of PAM-TDM.
The inputs are two speech signals.I want to have 16KHz as the sampling frequency.I need to generate two such generators with some phase difference between them.The time period corresponding to 16KHz will be 62.5µs.The pulse width of 12.5µs would do the job.
The signals are shown in the attached document.I have performed the simulation of the circuit using multisim and it gives satisfactory response.
Any ideas on how to generate the pulse generators with 12.5µs delay between pulses?
I can use 555 to generate two different pulse generator or I can even use the function generators available in the lab.The main issue is how to get the desired time delay.

 

[ronv]

Have you thought of 3 555's? one for the first pulse that triggers 2 for the delay that triggers 3 for the 2nd pulse?

 

[legend killer]

Have you thought of 3 555's? one for the first pulse that triggers 2 for the delay that triggers 3 for the 2nd pulse?

Thanks for the reply ronv,
i tried to simulate the circuit as you said,but i am not getting proper output.
I first made an astable multivibrator with pulse width of 12.5us,then for the delay i am supposed to give the output to monostable multivibrator which get triggered on the -ve edge,but i am not able to get 12.5us pulse.
So how to accomplish this?
Hope to get help.

 

[crutschow]

Please post a circuit of what you've done.

The first 555 is configured as an astable that generates 16KHz.

The second 555 is a configured as a monostable with a period of 12.5µs, that is triggered by the first 555.

The third 555 is configured as a monostable with a period of 31.25µs that is triggered by the falling edge of the second 555.

The third 555 thus will have a 16KHz output squarewave that is delayed by 12.5µs from the output of the first.

 

[legend killer]

thanks crutschow for replying,
I have attahed the circuit which I tried to simulate.The first is astable configuration with 80% duty cycle,so I added a not gate with it.The second is the monostable configuration with pulse width of 12.5 micro sec.Anyhow I am not able to get the pulse of 12.5microsec from the monstable config.
Hope u can help.

 

[crutschow]

So what pulse width do you get?