Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
234 words
A radio transmission system for transmitting a carrier frequency signal frequency modulated by an information amplitude modulated subcarrier frequency signal, comprising: first means for supplying a base frequency signal, second means responsive to said first means for generating a subcarrier frequency signal in a non-audible frequency band an amplitude modulator coupled to said second means for amplitude modulating the subcarrier frequency signal with an information signal; third means responsive to said second means for generating an announcement recognition frequency signal and a radio station recognition frequency signal; a memory coupled to said third means and having stored therein data representative of (1) the frequency of the announcement recognition frequency signal; (2) the frequency of the radio station recognition frequency signal; (3) the degree of amplitude modulation of the subcarrier for the announcement recognition frequency signal, and (4) the degree of amplitude modulation of the subcarrier for the radio station recognition frequency signal; said memory controlling the third means in accordance with data therein; means to provide said announcement and radio station recognition frequency signals to said amplitude modulator as said information signal; selector switch means connected to and selectively controlling the memory to furnish data to the third means and thereby control the third means to amplitude modulate the subcarrier in accordance with selected frequencies and degrees of amplitude modulation; and means to frequency modulate a carrier frequency signal with said amplitude modulated subcarrier.
Claim 2
Dependent Claim
234 words
A radio transmission system for transmitting a carrier frequency signal frequency modulated by an information amplitude modulated subcarrier frequency signal, comprising: first means for supplying a base frequency signal, second means responsive to said first means for generating a subcarrier frequency signal in a non-audible frequency band an amplitude modulator coupled to said second means for amplitude modulating the subcarrier frequency signal with an information signal; third means responsive to said second means for generating an announcement recognition frequency signal and a radio station recognition frequency signal; a memory coupled to said third means and having stored therein data representative of (1) the frequency of the announcement recognition frequency signal; (2) the frequency of the radio station recognition frequency signal; (3) the degree of amplitude modulation of the subcarrier for the announcement recognition frequency signal, and (4) the degree of amplitude modulation of the subcarrier for the radio station recognition frequency signal; said memory controlling the third means in accordance with data therein; means to provide said announcement and radio station recognition frequency signals to said amplitude modulator as said information signal; selector switch means connected to and selectively controlling the memory to furnish data to the third means and thereby control the third means to amplitude modulate the subcarrier in accordance with selected frequencies and degrees of amplitude modulation; and means to frequency modulate a carrier frequency signal with said amplitude modulated subcarrier.
Claim 3
Dependent Claim
17 words
A system according to claim 1, wherein said memory further stores data representative of humanly recognizable indicia.
Claim 4
Dependent Claim
46 words
A system according to claim 1, further including controlled connection means connected between the third means and the providing means for controlling the degree of amplitude modulation of the subcarrier by one of said announcement and radio station recognition frequency signals in dependence on the other.
Claim 5
Dependent Claim
51 words
A system according to claim 1, wherein said third means includes modulation control means, said memory controlling the modulation control means to control the degree of modulation being effected by said amplitude modulator in accordance with data stored in said memory, and selected for said control by said selector switch means.
Claim 6
Dependent Claim
39 words
A system according to claim 1, wherein said third means includes a controllable low-pass filter, said filter being connected to and controlled by said memory to control its filter range in accordance with frequency data stored in the memory.
Claim 7
Dependent Claim
40 words
A system according to claim 1, wherein said second means comprises a phase-locked loop including, a phase comparator and means for applying a control signal which is phase-shifted by 90° with respect to the base frequency, to said phase comparator.
Claim 8
Dependent Claim
46 words
A system according to claim 6, wherein said means for supplying the 90° phase-shifted signal comprises a 2:1 frequency divider and an exclusive-OR gate coupled to said frequency divider and having applied thereto said base frequency and a base-related frequency, and providing the phase-shifted output signal.
Claim 9
Dependent Claim
41 words
A system according to claim 6, wherein said second means further comprises an external quartz oscillator; and selectively connectable connection means in circuit with said phase-locked loop and coupled to said oscillator to selectively provide an oscillator output to said subcarrier.
Claim 10
Dependent Claim
44 words
A system according to claim 8, wherein said second means further includes signal recognition means connected to receive the base frequency, if present, and providing an output signal selectively connecting said external quartz oscillator, if and only if said base frequency should be absent.