Universal automotive electronic radio
First Claim
1. An electronic radio comprisinga plurality of input RF front ends, including at least one AM front end and one FM front end, each front end including an RF filter tunable over a desired band to pass selected signals to its output,band switching means for selecting a desired front end output,means frequency variable to translate each selected front end output to a common predetermined intermediate frequency, which common intermediate frequency is selected to be substantially higher than the frequency of the AM front end signals;
- means tuning the front ends and the translator,means amplifying and filtering the intermediate frequency signal,means demodulating the signal from the intermediate frequency amplifying and filtering means, andaudio reproducing means amplifying the demodulated output and transducing the resultant signal to audibility.
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Abstract
Selected radio circuits are fabricated on modules which plug into a "mother" board located in the radio chassis. The circuitry includes a plurality of RF front ends (including at least one AM and one FM front end), each tunable over a selected radio band by tuner circuitry. The AM front end includes a saturable core reactor whose tuning inductance varies as a function of the tuning current provided to it by a voltage-to-current converter in the tuner.
Both AM and FM signals are translated by a frequency synthesizer to a common IF frequency, namely 10.7 MHz. The synthesizer employs a quartz crystal controlled oscillator feeding a phase lock loop whose frequency is varied via the tuning control. Quartz crystal filters for AM, and ceramic filters for FM provide required selectivity. As all signals are at the same IF, a common IF amplifier is employed. Further, a single phase lock loop is adapted to demodulate both AM and FM signals.
The resultant demodulated signals are amplified, and tone shaped, via D. C. voltage controlled audio processor circuitry. The audio circuitry is adapted to accept auxiliary inputs, such as the output of a tape player.
A digital display senses tuner status providing frequency read out. Additional provisions allow switching the display to read out tape player status, or to provide a time display from an electronic clock.
88 Citations
57 Claims
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1. An electronic radio comprising
a plurality of input RF front ends, including at least one AM front end and one FM front end, each front end including an RF filter tunable over a desired band to pass selected signals to its output, band switching means for selecting a desired front end output, means frequency variable to translate each selected front end output to a common predetermined intermediate frequency, which common intermediate frequency is selected to be substantially higher than the frequency of the AM front end signals; -
means tuning the front ends and the translator, means amplifying and filtering the intermediate frequency signal, means demodulating the signal from the intermediate frequency amplifying and filtering means, and audio reproducing means amplifying the demodulated output and transducing the resultant signal to audibility. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An electronic radio comprising
a plurality of input RF front ends, including at least one AM front end and one FM front end, each front end including an RF filter tunable over a desired band to pass selected signals, each FM filter including a reverse biased silicon diode whose tuning capacitance varies predeterminedly in response to a tuning signal, each AM filter including a saturable reactor whose tuning inductance varies predeterminedly in response to a tuning signal, each AM front end further including a voltage controlled attenuator connected in series therewith for controlling the output amplitude level of the AM front end; -
band switching means operable to pass the signal from a selected front end, means frequency variable to translate each selected front end output to a common predetermined intermediate frequency including a plurality of mixers, each mixer corresponding to one of the front ends and having a pair of inputs, an output, and internal circuitry for producing at the output the modulated product of the two inputs, and a synthesizer having internal circuitry and a plurality of outputs, each output coupled to a corresponding mixer second input, the internal circuitry responsive to a tuning signal to produce at each output a signal, of a predetermined frequency, which is suitable for translating the selected front end signal to the intermediate frequency, means tuning the front ends and translator comprising a manually operable control, internal circuitry, and a plurality of outputs, selected outputs coupling to corresponding front end filters, a selected output coupled to the internal circuitry of the synthesizer, the synthesizer internal circuitry responsive to the manual control to produce a predetermined tuning signal at each output suitable for proper radio tuning, means amplifying and filtering the intermediate frequency signal in a predetermined manner, means demodulating the signal from the intermediate frequency amplifying and filtering means, the demodulator using a phase lock loop to demodulate FM signals and using the phase lock loop and a coherent detector to demodulate AM signals, manually operable DC controls; audio reproducing means amplifying the demodulated output and transducing the amplified signal to audibility including internal circuitry which is responsive to the manually operable DC controls to predeterminedly alter the frequency and amplitude characteristics of the amplified signal, and a digital display means sensing the status of the band switch and tuner and producing an illuminated readout representative of the radio tuning. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. The front end of an FM/AM tuner comprising
first circuit means passing selected frequencies in the FM band, second circuit means passing selected frequencies in the AM band, third circuit means translating the selected frequencies in each band to a common intermediate frequency, said common intermediate frequency selected to be substantially higher than the selected frequencies of the AM band, and means selecting the frequencies to be passed and translated.
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57. The front end of an FM/AM tuner comprising
an FM RF filter having an input and an output, the input receiving RF signals, the filter tunable to pass selected frequencies in the FM band to the output, an FM mixer having first and second inputs and an output, the mixer producing at its output the modulated product of its inputs, the first mixer input coupled to the FM RF output, an FM local oscillator having its output coupled to the FM mixer second input, the FM local oscillator tunable over a range of frequencies selected to translate the selected FM frequencies to a predetermined intermediate frequency, an AM RF filter having an input and an output, the input receiving RF signals, the filter tunable to pass selected frequencies in the AM band to the output, an AM mixer having first and second inputs and an output, the mixer producing at its output the modulated product of its inputs, means coupling the output of the AM RF filter to the first input of the AM mixer, and an AM local oscillator having its output coupled to the AM mixer second input, the AM local oscillator tunable over a range of frequencies selected to translate the AM selected frequencies to the predetermined intermediate frequency.
Specification