I need to introduce a programmable delay in my pattern Generator.. 1MHZ to 100MHz only... problem is.. Available IC is limited by the Pulse width of the signal.
If I will get the minimum possible pulsewidth (around 6.5ns), the stepping is very small, but to achieve a 1ns stepping my min pulse width is already around 20ns..
One uncalibrated method would be to vary the supply voltage on a string of inverters.
Also, there are some ECL delay chips. You will have to go to and from ECL which is another bother.
A further way is the analog microwave phase shift method of using PIN diodes to switch in different lengths of transmission line or LC network equivalents. Instead of the PIN diodes, you could use selecting gates.
Yes, I already looked at dallas and maxim, even analog...
But the effectivity is still limited to the minimum pulse witdh...
so I guess I have to cascade delay lines in order to reach a wider range of operating frequency.
I'll get the device with the least min. pulse width requirement and cascade 2 or more so that I could reach the longer delay without being handcuffs by the min pulse width requirement.