I made an NCO based sinewave generator which produces variable frequency output up to 25 MHz 1V pk to pk output.
I need to convert this frequency to pulses and my first thought was as follows:

1. Amplify this signal to 10v pk to pk.

Is this a desired/required output?

2. use half wave rectifier.

For what purpose?

3. Use the amplified signal to drive Schmitt trigger input of 74121 monostable multivibrator to produce a narrow pulse on every rising edge.

This won't work, as the 74xxx family won't operate at the 10-volt p-p levels.

Is this a desired/required output?

4. job Done.

What was the job?

My problem is the amplifier. I couldn't make a large bandwidth amplifier for both low frequency and high frequency together.
Do you have any other ideas for doing the same job or wide bandwidth amplifier.

Why? When you set frequency range of your oscillator, you can simply select a different output amplifier. You can, of course, use any of several wideband amplifiers, some of which have very hefty (30V p-p into 50-ohms) outputs, yet can be pretty stabile at low frequency. If you need lots of precision, you may be out of luck, but if you don't mind a bit of error, then using analog switches to mux the various passives around an amplifier, you can tailor the amp behavior to what you need. Modern switches have ~1 ohm on-resistance. Against 1-KOhm resistances, that's pretty small error.

RE