| 摘要 |
<p>FREQUENCY AGILE SATELLITE RECEIVER A low cost, frequency agile receiver for earth satellite ground stations provides selection of any one of 24 channels available from an RCA synchronous orbit satellite. The tuner of the receiver utilizes mass produced elements including CB synthesizer, divider and PKOM chips to control the frequency of a conventional VCO operating at about 500 MHz. Multiplication of the VCO frequency by conventional techniques and further use of a double diode sub-harmonic mixer, low beat local oscillator mixing and use of the different mixer signals (down conversion) permits reduction of 3.72 GHz to 4.18 GHz signals in two mixer stages to 70 MHz IF with sixth-sevenths of the reduction occurring in the first mixer whereby low cost printed circuit filters may be employed to eliminate problems associated with satellite transponder images and adjacent channel IF frequencies produced in the first mixer. File No. PAT6101</p> |
