455khz Ceramic Filter Circuit
Mouser offers inventory pricing datasheets for murata ceramic filters 455 khz signal conditioning.
455khz ceramic filter circuit. The ceramic filter has now become very hard to find. Murata makes the cerafil r line of ceramic filters some of which are designed for use at 455khz and 450khz. A search of ebay for filter if 455 turns up units like the avx kyocera kbf455r which may be suitable for your project. The ceramic filter gives good frequency stability and requires no adjustment in order to produce the correct frequency.
A significant amount of feedback is provided only at the operating frequency of the filter which is 455 khz. Homebrew 455khz ceramic if filter so today after reading some more of soldersmoke global adventures in wireless electronics and feeling somewhat enthusiastic about advancing some projects i went out to my work bench and soldered up a test rig used to determine the motional parameters of crystals and in my case ceramics. The original version of the circuit also had a fixed output impedance of about 300 ohms but it required an additional transistor connected as an emitter follower. Therefore i revised the circuit replacing the ceramic filter with a simple lc filter.
Simplest 455 khz oscillator uses only three parts negative resistance ceramic filter oscillator ceramic resonator oscillator rf oscillator with three parts the simplest oscillator ever if anyone can successfully disprove this claim i ll gladly retract it. The murata ht series is a bit wider and is defined as not less than 6 khz in reality these are measured as 7 5 to 8 7 khz exactly. Murata ceramic filters 455 khz signal conditioning are available at mouser electronics. For example the sfpla450kd1a b0 has a 6db bandwidth of 10khz designed for use with am stereo receivers.
Filters for am applications sfgcg sfpc cfucg 455khz along with the development of the am chip filter if filters for am fm radios have also been made smaller thinner and in a chip configuration for surface mounting. Electronics electronic components electronic parts electronic kits hobby electronics surplus electronics diy electronics discount electronics electronic. This is one more example of murata electronics leadership in converting conventional electronic components to chip. A better option may be to put the filter into a feedback circuit.
Also some filter series are up to 1 to 1 5 khz squint i mean by squint off center thus shifted from 455 000 hz exactly. So the circuit oscillates at this frequency. Feb 6 2017 9. Also see that the ceramic filter is connected to 5v in that schematic but my ceramic filter only has 1 input 1 output and 3 ground pins.