charlie@oakhill.UUCP (Charlie Thompson) (04/21/89)
I am looking for something to use as an ultrsonic microphone. I have a little 25KHz ultrsonic transducer but it is resonant at 25KHz and offers a very narrow bandwidth around 25. I'd like to have something with a broader response. I tested a cheapie condenser mic and it seems to work at 25K pretty well. The intended application is a tuneable untrasonic receiver of the heterodyne/homodyne variety and hence the need for broad-bandedness. Coverage up to 40KHz is desireable. Charlie Thompson WB4HVD Austin,TX
ben@val.UUCP (Ben Thornton) (04/25/89)
In article <1989@otis.oakhill.UUCP> charlie@oakhill.UUCP (Charlie Thompson) writes: >I am looking for something to use as an ultrsonic microphone. >I have a little 25KHz ultrsonic transducer but it is resonant >at 25KHz and offers a very narrow bandwidth around 25. I'd like >to have something with a broader response. I tested a cheapie >condenser mic and it seems to work at 25K pretty well. The >intended application is a tuneable untrasonic receiver of the >heterodyne/homodyne variety and hence the need for broad-bandedness. >Coverage up to 40KHz is desireable. Hmmm... how about one of those cheap electret pellet microphones? These are the kind that are built into small cassette tape recorders and hand-picked ones are used as the element in a PZM. They are normally bandwidth-limited by the circuit they are used in, but I think they will actually respond well into the ultrasonic range. . . . . . . . -- Ben Thornton packet: WD5HLS @ KB5PM Video Associates Labs uucp: ...!cs.utexas.edu!oakhill!val!ben Austin, TX fidonet: 1:382/40 - The Antenna Farm BBS
martens@wasatch.utah.edu (William G Martens) (04/26/89)
In article <328@val.UUCP>, ben@val.UUCP (Ben Thornton) writes: > > >I am looking for something to use as an ultrsonic microphone. > >I have a little 25KHz ultrsonic transducer but it is resonant > >at 25KHz and offers a very narrow bandwidth around 25. I'd like > >to have something with a broader response. I tested a cheapie In a small 1977 edition of their 'Pressure Transducer Handbook' National Semi. lists a pressure transducer recommended fr audio use, p/n LX1701G or LX1701A, that they claim is good from dc to 50khz! I don't know if they are available now, (12 years later)? William Martens UofUtah Comp Sci Dept.