Post by thread:ceramic resonators...

My turn for what should be a simple question... Are "ceramic filters" the same as "ceramic resonators" ? I can go into the local surplus store and find little three-lead devices labled "ceramic filters" in all sorts of nice frequencies (ie 6MHz.), as well as "ceramic resonators" in a more limitted range (3.58MHz) Will both of these work in the oscillator circuit of a PIC? Thanks bill W

>Are "ceramic filters" the same as "ceramic resonators" ? I can go into the >local surplus store and find little three-lead devices labled "ceramic filters" >in all sorts of nice frequencies (ie 6MHz.), as well as "ceramic resonators" >in a more limitted range (3.58MHz) Will both of these work in the oscillator >circuit of a PIC? > >Thanks >bill W The resonators will, but the filters have wider bandpass that could get into some real wierd operation. You could get them to oscillate in a series mode circuit, and they would run at some freq within their bandwidth (not necesarily the center!) but I'd be nervous that they might shift freqs with temp change. The filters are designed to pass a range of freqs, where a xtal is designed to pass (or be high impedance at) one frequency.

Crystal filters and maybe ceramic filters are used in radio stuff to pass only the desired frequence after mixing two signals. Bill C. spam_OUTbillTakeThisOuTcornutt.com ---------- {Quote hidden}> > >Are "ceramic filters" the same as "ceramic resonators" ? I can go into the > >local surplus store and find little three-lead devices labled "ceramic > filters" > >in all sorts of nice frequencies (ie 6MHz.), as well as "ceramic > resonators" > >in a more limitted range (3.58MHz) Will both of these work in the > oscillator > >circuit of a PIC? > > > >Thanks > >bill W > > > The resonators will, but the filters have wider bandpass that could get into > some > real wierd operation. You could get them to oscillate in a series mode > circuit, and > they would run at some freq within their bandwidth (not necesarily the > center!) but > I'd be nervous that they might shift freqs with temp change. > > The filters are designed to pass a range of freqs, where a xtal is designed > to pass > (or be high impedance at) one frequency. >

In message <.....CMM.0.90.4.896396420.billwKILLspam@spam@flipper.cisco.com>, William Chops Westfield <billwKILLspamCISCO.COM> writes >My turn for what should be a simple question... > >Are "ceramic filters" the same as "ceramic resonators" ? I can go into the >local surplus store and find little three-lead devices labled "ceramic filters" >in all sorts of nice frequencies (ie 6MHz.), as well as "ceramic resonators" >in a more limitted range (3.58MHz) Will both of these work in the oscillator >circuit of a PIC? These filters are designed to be used as frequency-selective devices in radio receivers, rather than as simple resonators. They are unlikely to work properly in an oscillator circuit, as they actually consist of two resonators coupled together. Although they have three legs, they don't incorporate the capacitors necessary for oscillator operation. If you clip off one of the outer pins, it'll probably work as a simple resonator. I'd be inclined to try it and see what happens. 8-) Leon -- Leon Heller: .....leonKILLspam.....lfheller.demon.co.uk http://www.lfheller.demon.co.uk Amateur Radio Callsign G1HSM Tel: +44 (0) 118 947 1424 See http://www.lfheller.demon.co.uk/dds.htm for details of my AD9850 DDS system. See " "/diy_dsp.htm for a simple DIY DSP ADSP-2104 system.