Radio information broadcasting and receiving system
First Claim
1. A radio information broadcasting system comprising:
- a broadcast transmitter means including a source of main program audio input signals at a carrier frequency, at least first and second sources of digital data input signal, a first subcarrier means connected to a first one of said at least first and second sources of digital data input signals for providing a digitally modulated signal at a first subcarrier frequency and at least a second subcarrier means connected to a second one of said at least first and second sources of digital data input signals for providing a digitally modulated signal at a second subcarrier frequency, wherein said first digital data input signals consists of text encoded into a relatively long string of digital signals representative of a plurality of separate subject indices and said at least second digital data input signals consists of index data related to the separate subject indices of said text data of said first digital data signals, said index data being encoded into a relatively long string of digital data signals, an analog signal mixer means connected to said source of main program audio input signals, and to said first and to said at least second digitally modulated signals at said first and at least second subcarrier frequency to provide a combined main program carrier signal and at least two subcarrier frequency signals on a baseband, means for frequency modulating said combined signals from said analog signal mixer and means for repeatedly transmitting said frequency modulated combined signal for a given period of time, said radio information broadcasting system further including a receiving means including frequency modulation receiver and demodulating circuits for receiving said repeatedly transmitted frequency modulated combined signal from said broadcast transmitter means and demodulating said received repeatedly transmitted frequency modulated combined signal into a main program frequency signal, and at least first and second subcarrier frequency signals, filter means responsive to the outputs of said demodulating circuits for separating the frequency bands of said first and second subcarrier frequency signals from said main program audio signal, an audio output circuit having a speaker connected to said demodulated main program signal, subcarrier frequency generating means for generating first and second subcarrier frequencies and data demodulation means connected to said subcarrier frequency generating means and responsive to said separated frequency bands of at least first and second subcarrier frequency signals for demodulating the data thereon to provide at least first and second digital data signals transmitted by said broadcast transmitter, said receiving means further including,a digital data processing computer means response to said data demodulator means including a storage memory responsive to said first and second digital data signals therefrom for storing said first and second digital data signals from said data demodulator means in said memory and for performing first and second levels of error correction on said stored first and second digital data signals wherein said first level of error correction is bit error correction and said second level of correction and wherein said second level of error correction selects the one of the repeatedly transmitted combined signal with the least errors.
1 Assignment
0 Petitions
Accused Products
Abstract
A radio information broadcasting and receiving system consisting of three major parts: an FM transmitter station with subcarrier multiplexing capability, an FM receiver apparatus with subcarrier demodulation capability, and a computer connected in combination with the receiver apparatus. The FM transmitter station includes sources of main programming signals first digital data signals and second digital data signals. The first and second digital data signals are modulated by subcarrier 1 and subcarrier 2 frequencies respectively and are mixed with the main program signal and then transmitted. The transmitted signals are received by a receiver apparatus including an FM receiver circuit and an FM demodulator circuit for receiving the broadcast signal and demodulating it. The demodulated main program audio frequency signal is applied through a filter/deemphasis circuit and amplifier to speaker to provide an audio output. The first subcarrier frequency signal is demodulated by a first subcarrier frequency generator to provide a digital signal of the text portion of the transmitted signal which is then applied to a first input port of this digital computer. Likewise, the second subcarrier frequency is demodulated and the resultant index digital data signal is applied to a second input port of the computer.
-
Citations
7 Claims
-
1. A radio information broadcasting system comprising:
-
a broadcast transmitter means including a source of main program audio input signals at a carrier frequency, at least first and second sources of digital data input signal, a first subcarrier means connected to a first one of said at least first and second sources of digital data input signals for providing a digitally modulated signal at a first subcarrier frequency and at least a second subcarrier means connected to a second one of said at least first and second sources of digital data input signals for providing a digitally modulated signal at a second subcarrier frequency, wherein said first digital data input signals consists of text encoded into a relatively long string of digital signals representative of a plurality of separate subject indices and said at least second digital data input signals consists of index data related to the separate subject indices of said text data of said first digital data signals, said index data being encoded into a relatively long string of digital data signals, an analog signal mixer means connected to said source of main program audio input signals, and to said first and to said at least second digitally modulated signals at said first and at least second subcarrier frequency to provide a combined main program carrier signal and at least two subcarrier frequency signals on a baseband, means for frequency modulating said combined signals from said analog signal mixer and means for repeatedly transmitting said frequency modulated combined signal for a given period of time, said radio information broadcasting system further including a receiving means including frequency modulation receiver and demodulating circuits for receiving said repeatedly transmitted frequency modulated combined signal from said broadcast transmitter means and demodulating said received repeatedly transmitted frequency modulated combined signal into a main program frequency signal, and at least first and second subcarrier frequency signals, filter means responsive to the outputs of said demodulating circuits for separating the frequency bands of said first and second subcarrier frequency signals from said main program audio signal, an audio output circuit having a speaker connected to said demodulated main program signal, subcarrier frequency generating means for generating first and second subcarrier frequencies and data demodulation means connected to said subcarrier frequency generating means and responsive to said separated frequency bands of at least first and second subcarrier frequency signals for demodulating the data thereon to provide at least first and second digital data signals transmitted by said broadcast transmitter, said receiving means further including, a digital data processing computer means response to said data demodulator means including a storage memory responsive to said first and second digital data signals therefrom for storing said first and second digital data signals from said data demodulator means in said memory and for performing first and second levels of error correction on said stored first and second digital data signals wherein said first level of error correction is bit error correction and said second level of correction and wherein said second level of error correction selects the one of the repeatedly transmitted combined signal with the least errors. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
Specification