Hello Raghu,
I've done something similar to what you try to do. I just used a small low cost CPLD with a few lines of code in VHDL and that's it. What I did was simple but it works good:
1/Set up a N bit binary counter with reset signal (number of bits + clk frq will dictate your resolution)
2/Use the input signal to reset the counter
3/AND all N output then invert it + lowpass filter then feed it to analog meter or 1 stage of buffer/amp to fit the scale. Done
Hope this helps.

Regard,
T.L