RDS receiver with improved alternate frequency switchover
First Claim
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1. A radio data system (RDS) receiver comprisinga mixing stage (3);
- a first FM demodulator (11) connected to an output of said mixing stage (3);
an RDS decoder (16) having an input, connected to an output of said FM demodulator, and an output;
a first Phase-Locked Loop (PLL), including a divider (5), and having an output connected to said mixing stage (3); and
a microcomputer (17) having at least one output (9) connected to a control input of said divider (5);
and whereinthe output of said RDS decoder (16) is connected selectively to one of two inputs (18,
19) of the microcomputer (17), via a controllable changeover switch (23) controlled (24) by said microcomputer (17), to facilitate rapid checking of codes contained in RDS signals received at successively tuned different broadcast frequencies using a single demodulator and decoder.
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Abstract
In a radio receiver having a device for decoding radio data signals, which are divided into groups each with a predetermined number of bits and contain a program identification code, and having a device for switchover for switchover from a received frequency to an alternative frequency, by briefly switching over to the alternative frequency, a plurality of data samples are taken from various groups and at various times within the groups of the radio data signal that is received at the alternative frequency. The data samples are compared with a program identification code stored in memory.
37 Citations
13 Claims
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1. A radio data system (RDS) receiver comprising
a mixing stage (3); -
a first FM demodulator (11) connected to an output of said mixing stage (3); an RDS decoder (16) having an input, connected to an output of said FM demodulator, and an output; a first Phase-Locked Loop (PLL), including a divider (5), and having an output connected to said mixing stage (3); and a microcomputer (17) having at least one output (9) connected to a control input of said divider (5); and wherein the output of said RDS decoder (16) is connected selectively to one of two inputs (18,
19) of the microcomputer (17), via a controllable changeover switch (23) controlled (24) by said microcomputer (17), to facilitate rapid checking of codes contained in RDS signals received at successively tuned different broadcast frequencies using a single demodulator and decoder. - View Dependent Claims (2)
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3. In a radio receiver having a device (16) for decoding radio data signals, which signals are divided into groups, each with a predetermined number of bits and which contain a Program Identification (PI) code, and
a switchover device (22,23,37) for switchover from a received frequency, to an alternative frequency, in order to identify a Program Identification code of a radio data signal transmitted on the alternative frequency, a method of identifying said PI code on the alternative frequency while limiting duration of each switchover to a period of time less than the duration of reception of a complete radio data signal group consisting of said predetermined number of bits, said method comprising the steps of: -
limiting duration of each switchover from said received frequency to said alternative frequency to a limited period of time during which only a partial sample, of said radio data signal on said alternative frequency, can be taken, initiating switchovers at various times to take a plurality of data samples from various ones of said groups, and at various times within each group of the radio data signal, and comparing data samples taken with a Program Identification code stored in a memory in said receiver, for determining whether a match exists between said stored code and at least one of said samples. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification