design pulse generator circuit

[meysaminter]

hi
i want to build a pulse generator circuit with these SPECIFICATIONs:
1- pw = 20ns
2- f=5Mhz
3-( rt & ft )< 1ns
4- 10W
plz help me

 

[vleam13]

Use capacitor charge and discharge circuit and this will create triangular waveform. Feed this waveform to the buffer and it will become square wave after threshold voltage detected.

 

[dv_sa559]

I think you should use Schmitt trigger because rt&ft is very sharp.
Then you can drive high power BJT by your circuit.

 

[mtwieg]

What kind of load are you driving? 1ns rise and fall times will be very difficult to achieve unless your load is just resistive. Is 10W an average, RMS, or peak specification?

 

[meysaminter]

sorry my information war incorrect : the power is not important because the output must be TTL and
this circuit will be connected to a driver

---------- Post added at 08:52 ---------- Previous post was at 07:48 ----------

plz help me

 

[dv_sa559]

I think you can make this waveform by as-table multi-vibration circuit like :
**broken link removed**

 

[meysaminter]

any other idea?

 

[goldsmith]

Hey gentleman !
Hi
You can use a crystal oscillator Ic in 10 MHZ frequency and then dividing its frequency with D flip flop and then amplify it with A switch that works at Class D Region! it is very simple.
Kind Regards
Goldsmith

 

[meysaminter]

==== tanks man ======

---------- Post added at 12:54 ---------- Previous post was at 12:51 ----------

how about pw?

 

[mtwieg]

sorry my information war incorrect : the power is not important because the output must be TTL and
this circuit will be connected to a driver

---------- Post added at 08:52 ---------- Previous post was at 07:48 ----------

plz help me

You'll have to explain what the driver it's driving is, though. If it's a digital driver, I don't see why having such fast edges are needed for, but if it's an analog buffer circuit then it may be necessary, and difficult.

There are exotic ways of getting fast rise and fall times, but they're usually tailored to the exact load and waveform shape. For example, a friend of mine made a circuit using a nonlinear transmission line that can produce a 300V pulse with a <1ns fall time, but it's very specialized so the same thing may not work for you.

 

[meysaminter]

The Driver is analog and called modulator used for magnetron lump

 

[mtwieg]

you need to specify what the driver circuit is, or at least give its input impedance.

Also, what amplitude do you need for the pulse?

 

[meysaminter]

my friend these informations u asked did nat important i just want a puls generator with these specifications .

 

[meysaminter]

anybody can help me?

 

[mtwieg]

Your friend is wrong and it's very important. There's no point in designing a source when you don't know the load.