RDS data demodulator capable of precisely attenuating ARI signal
AssigneePioneer Electronic Corporation
InventorsYuji Yamamoto, Terukazu Kobayashi
Life of this patent
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Abstract
An RDS data demodulator includes an analog-to-digital converter for converting an analog FM signal into a digital FM modulation signal; a first filter having a transfer zero point at a predetermined frequency, for receiving the digital FM modulation signal and for attenuating an information modulation signal; a second filter having a pass band characteristic at the predetermined frequency, for receiving a filter output signal from the first filter and for extracting an RDS modulation signal; and RDS demodulating means for demodulating the RDS modulation signal from the second filter to output both an RDS data signal and a reproduction clock signal used to demodulate the RDS data signal.
Claims7
A radio data system (RDS) data demodulator comprising:
- an analog-to-digital converter for converting an analog FM signal into a digital FM modulation signal;
- a first, filter having a transfer zero point at a predetermined frequency, for receiving the digital FM modulation signal and for attenuating an information modulation signal;
- a second filter having a pass band characteristic at the predetermined frequency, for receiving a filter output signal from the first filter and for extracting an RDS modulation signal;
- and
- RDS demodulating means for demodulating the RDS modulation signal from the second filter to output both an RDS data signal and a reproduction clock signal used to demodulate the RDS data signal.
A radio data system (RDS) data demodulator comprising:
- an analog-to-digital converter for converting an analog FM signal into a digital FM modulation signal;
- a first filter having a transfer zero point at a predetermined frequency, for receiving the digital FM modulation signal and for attenuating an information modulation signal;
- a second filter having a pass band filter characteristic at the predetermined frequency, for receiving a filter output signal from the first filter and for extracting an RDS modulation signal;
- and
- a demodulator for demodulating the RDS modulation signal from the second filter to output both an RDS data signal and a reproduction clock signal used to demodulate the RDS data signal.
A method for demodulating data to a radio data system comprising:
- converting an analog FM signal into a digital FM signal;
- attenuating an information modulation signal of a predetermined frequency within the digital FM signal;
- extracting an RDS modulation signal from the digital FM signal, after the attenuation of the information modulation signal;
- demodulating an RDS modulation signal extracted by the extracting operation to obtain an RDS data signal;
- and
- outputting the RDS data signal and a reproduction clock signal used to demodulate the RDS data signal,
- wherein the attenuating operation is executed by a first infinite impulse response type filter and the extracting operation is executed by a second infinite impulse response type filter, each of the first infinite impulse response type filter and the second infinite impulse response type filter has a transfer function of H(Z)=(B+B1Z−1+B2Z−2)/(1−A1Z−1−A2Z−2), parameters of the transfer function of the first infinite impulse response type filter are A1=B1=0, B=B2, parameters of the transfer function of the second infinite impulse response type filter are A1=B1=0, B=−B2, the coefficient “A1” being a factor for determining a pass-band blocking frequency, or a pass-band central frequency of the filter, the coefficient “A2” being a factor for determining “Q” of the filter, and the coefficient “B” denoting an element used to determine an amplification factor of input/output in a pass band.
Dependencies are inferred from the claim text.