High frequency Varaible Pulse Gen

[rahulksgift]

Hi All,

I would like to make a Variable Pulse generator with Following Features

: programmable width and frequency (i.e.,

programmable frequency and duty cycle). Pulse width should

range from 1ns to 10 ns. Programming will be from a

microcontroller (MSP or a 32 bit) with digital IOs. Pulse

train frequency 1-20 MHz preferred (3-10 MHz minimum).

Can Any one Advice Me!!!

Thanks.

 

[tejashs]

choose a microcontroller that has a built in PWM module...

 

[FvM]

choose a microcontroller that has a built in PWM module...

No micro has a PWM time resolution of 1 ns. FPGAs with fast IO standards (LVDS) and hardware SERDES unit can do, also discrete ECL logic devices.

 

[rahulksgift]

Thanks for your Valuable comment !!!Im Interested in ECL Devices, but Is it possible to program its Duty Cycle from a controller?

 

[FvM]

but Is it possible to program its Duty Cycle from a controller?

This surely ends up in a complex circuit comprised of several ECL MSI devices. Onsemi has a large portfolio of ECL ICs, also including complex devices like counters and shift registers.

 

[chuckey]

With pulses this narrow, I would design it from the output socket, backwards and just use the micro as a controller of switches and nothing more. If you build a delay line with varactor capacitors, then you can electronically control the capacitance and hence the delay, gating the input pulse with the output pulse should get you a variable and very narrow output pulse (use ECL).
Frank

 

[FvM]

Using analog circuits for the pulse generator is still an option. But you can achieve about 100 ps timing resolution of adjustable pulsewidths using recent low cost FPGAs, together with effectively unlimited waveform complexity. There will be always room for analog solutions of special problems. But once you have learned to manage the digital methods, you'll appreciate their performance.