Radio information broadcasting and receiving system

• US 5,581,576 A
• Filed: 01/12/1995
• Issued: 12/03/1996
• Est. Priority Date: 01/12/1995
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Mok, Lawrence S., Lanzetta, Alphonso P.
• Primary Examiner(s): Bocure, Tesfaldet
• Application Number:
  US08/371,621
• Time in Patent Office: 691 Days
• Field of Search: 455/6.3, 455/45, 455/133, 455/186.1, 381/2, 381/77, 381/14, 375/259, 375/260, 375/216, 375/271, 375/272, 375/268, 375/300, 375/303, 375/320, 375/334, 375/267, 375/299, 375/347, 375/316, 375/295, 332/117, 332/151, 332/149, 332/144, 332/100, 329/315, 329/300, 329/345, 329/347, 329/348, 370/110.4, 370/110.1, 371/30
• US Class Current: 375/216
• CPC Class Codes: H04H 20/34 using an out-of-band subcarrier signal
• CPC Class Codes: H04H 20/86 Arrangements characterised by the broadcast information itself
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26

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.

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.

2. A radio information broadcasting system according to claim 1 wherein said first subcarrier means of said broadcast transmitter includes a first data modulator circuit connected to said first source of digital data input signals, a first subcarrier frequency generator connected to said first data modulator circuit for modulating said text encoded first digital data signals with a first subcarrier frequency signal, and means connecting said modulated first digital data signals to said analog signal mixer means and wherein said second subcarrier means of said broadcast transmitter includes a second data modulator circuit connected to said second source of index encoded-digital data input signal, a second subcarrier frequency generator connected to said second data modulator circuit for modulating said second digital data signals with a second subcarrier frequency signal, and means for connected said modulated second digital data signals to said analog signal mixer means.

3. A radio information broadcasting system according to claim 2 wherein said receiving means includes a first demodulating means including a first band-pass filter circuit connected to said first one of said transmitted digital data signals, a first data demodulator circuit connected to the output of said first band-pass filter circuit, and a first subcarrier frequency generator circuit connected to said first data demodulator circuit for demodulating said first one of said transmitted digital data signals onto a first output lead,

and a second demodulating means including a second band-pass filter circuit connected to said second one of said transmitted digital data signals, a second data demodulator circuit connected to the output of said second band-pass filter circuit, and a second subcarrier frequency generator circuit connected to said second data demodulator circuit for demodulating said second one of said transmitted digital data signals onto a second output lead.

4. A radio information broadcasting system according to claim 3 further including a digital data processing computer means including a storage memory connected to said first and second output leads of said receiving means for storing said demodulated first and second digital data signals in said memory, and further including a display means for displaying said text of said first digital data signals.

5. A radio information broadcasting system according to claim 4 wherein said text data displayed on said display means of said digital data computer means is selected in accordance with said index data.

6. A radio information broadcasting system according to claim 4 wherein said index encoded second digital data signals are transmitted repeatedly for each transmission of said text encoded first digital data signals.

7. A radio information broadcasting system according to claim 4 wherein said first and second digital data signals include data bits for identification numbers, control bits and error detection bits, and wherein said digital data processing computers means performs error detection on said first and second digital data signals.