mayo Posted April 6, 2004 Report Posted April 6, 2004 I want to experiment and I need diagrams of PLL based FM tranmitters (for ic: 4046 o 4076)Please send me to: [email protected]or post a linkThanks. Quote
hotwaterwizard Posted April 10, 2004 Report Posted April 10, 2004 Here is the first Datasheet.HCC_HCF_4046B.pdf Quote
hotwaterwizard Posted April 10, 2004 Report Posted April 10, 2004 Here is the second DatasheetHCC_HCF_4076B.pdf Quote
audioguru Posted April 13, 2004 Report Posted April 13, 2004 Hi Mayo,I hope that you do not want to transmit on the FM broadcast band of 88 to 108 MHz because the VCO in the 4046 has a typical max. frequency of only 0.8 to 2.4MHz (page 7 on data sheet).A broadcast band FM transmitter needs an 88 to 108MHz VCO which feeds a very high frequency digital divider. If you want to transmit on 100MHz then divide that down to 1MHz to feed one side of a phase comparator (you can use the 4046 phase comparator) and the reference frequency would be an accurate 1MHz crystal oscillator. Then you can frequency-modulate that oscillator a little with a varactor. The small amount of FM at the oscillator is multiplied by the divider (but also its frequency inaccuracy and drift). Quote
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