sllu@jenny.isi.edu (Shih-Lien Lu) (02/07/91)
Wisdom of the net: What are some ways to implement delays for analog signals (dealy in 1 ns resolution)? One possible way is to have the equiv. of an R/2R ladder. Is there any other way, in particular, to implement on an IC? Thanks in advance. Shih-Lien
ftpam1@acad3.alaska.edu (MUNTS PHILLIP A) (02/07/91)
In article <16663@venera.isi.edu>, sllu@jenny.isi.edu (Shih-Lien Lu) writes... >Wisdom of the net: > >What are some ways to implement delays for analog signals (dealy in 1 ns >resolution)? >One possible way is to have the equiv. of an R/2R ladder. >Is there any other way, in particular, to implement on an IC? >Thanks in advance. > >Shih-Lien How about microstrip transmission lines? The delay will be 1 ns/foot times the dielectric constant of the circuit board material. Find a microwave or ECL book for details. Philip Munts N7AHL NRA Extremist, etc. University of Alaska, Fairbanks
whit@milton.u.washington.edu (John Whitmore) (02/07/91)
In article <16663@venera.isi.edu> sllu@ISI.EDU (Shih-Lien Lu) writes: >What are some ways to implement delays for analog signals (dealy in 1 ns >resolution)? >One possible way is to have the equiv. of an R/2R ladder. >Is there any other way, in particular, to implement on an IC? You can use a SAW (surface acoustic wave) device with multiple taps (select the tap for the required delay). There is an interesting property of GaAs: it is piezoelectric. So, at least one company (whose name I can get, given time to look up the guy who told me...) which has a GaAs SAW device with multiple taps connected through multiplying D/A converters to a summing junction. They are doing real-time FIR filtering that way. A linear CCD device with variable input clock frequency could do it, but only for low-frequency input signals. A modulated light beam can be delayed by bouncing it off a mirror (and moving the mirror); a Scotchlite retroreflective panel moved 15 cm would give you a nanosecond's delay. This, of course, would mean mechanical motion for change in delay time. John Whitmore