Radio receiver

Claim 2

A radio receiver for receiving a radio signal comprising: means receiving and converting said radio signal into an IF signal; a first demodulating circuit which is a pulse count demodulating circuit and a second demodulating circuit other than a pulse count demodulating circuit, both demodulating circuits being responsive to said IF signal; a detecting circuit for generating a field strength signal related to the received electric field intensity of said radio signal; and a switching circuit selectively outputting a demodulation signal from said first demodulating circuit and a demodulation signal from said second demodulating circuit in response to said field strength signal.

Claim 3

A radio receiver of claim 1 further comprising a switching level control circuit which selectively activates said switching circuit to supply said demodulation signal from said first demodulating circuit under a received electric field intensity equal to and higher than a first level and to supply said demodulation signal from said second demodulating circuit under a received electric field intensity equal to or lower than a second level which is smaller than said first level.

Claim 4

A radio receiver for receiving a radio signal comprising: means receiving and converting said radio signal into an IF signal; a first demodulating circuit which is a pulse count demodulating circuit and a second demodulating circuit other than a pulse count demodulation circuit, both demodulating circuits being responsive to said IF signal; a detecting circuit for generating a field strength signal related to the received electric field intensity of said radio signal; a switching circuit selectively supplying a demodulation signal from said first demodulating circuit and a demodulation signal from said second demodulating circuit in response to said field strength signal; a noise elimination circuit for removing noises contained in one of said demodulating signals supplied from said switching circuit; and a noise elimination circuit controller responsive to the received electric field intensity to change the degree of the noise eliminating operation of said noise elimination circuit.

Claim 5

A radio receiver for receiving a radio signal comprising: means receiving and converting said radio signal into an IF signal; a first demodulating circuit which is a pulse count demodulating circuit and a second demodulating circuit other than a pulse count demodulation circuit, both demodulating circuits being responsive to said IF signal; a detecting circuit for generating a field strength signal related to the received electric field intensity of said radio signal; a switching circuit selectively supplying a demodulation signal from said first demodulating circuit and a demodulation signal from said second demodulating circuit in response to said field strength signal; a noise elimination circuit for removing noises contained in one of said demodulating signals supplied from said switching circuit; and a noise elimination circuit controller responsive to the received electric field intensity to change the degree of the noise eliminating operation of said noise elimination circuit.

Claim 6

A radio receiver for receiving a radio signal comprising: means receiving and converting said radio signal into an IF signal; a first demodulating circuit which is a pulse count demodulating circuit and a second demodulating circuit other than a pulse count demodulating circuit, both demodulating circuits being responsive to said IF signal; a detecting circuit for generating a field strength signal related to the received electric field intensity of said radio signal; a switching circuit selectively supplying a demodulation signal from said first demodulating circuit or a demodulation signal from said second demodulating circuit in response to said field strength signal; a stereo demodulation circuit receiving a stereo demodulation signal which is one of said demodulation signals supplied from said switching circuit, to reproduce an L-channel signal and an R-channel signal from said stereo demodulation signal; a separation circuit responsive to said field strength signal to control the degree of channel separation of said stereo demodulation circuit; a high-cut circuit responsive to said field strength signal to attenuate high band components of said L-channel signal and R-channel signal supplied from said stereo demodulation circuit; and a separation/high-cut controller interrupting or minimizing operations of said high-cut circuit and separation circuit when said stereo demodulation signal supplied from said switching circuit is said demodulation signal from said first demodulating circuit.

Claim 7

A radio receiver for receiving a radio signal comprising: means receiving and converting said radio signal into an IF signal; a first demodulating circuit which is a pulse count demodulating circuit and a second demodulating circuit other than a pulse count demodulating circuit, both demodulating circuits being responsive to said IF signal; a detecting circuit for generating a field strength signal related to the received electric field intensity of said radio signal; a switching circuit selectively supplying a demodulation signal from said first demodulating circuit or a demodulation signal from said second demodulating circuit in response to said field strength signal; a stereo demodulation circuit receiving a stereo demodulation signal which is one of said demodulation signals supplied from said switching circuit, to reproduce an L-channel signal and an R-channel signal from said stereo demodulation signal; a separation circuit responsive to said field strength signal to control the degree of channel separation of said stereo demodulation circuit; a high-cut circuit responsive to said field strength signal to attenuate high band components of said L-channel signal and R-channel signal supplied from said stereo demodulation circuit; and a separation/high-cut controller interrupting or minimizing operations of said high-cut circuit and separation circuit when said stereo demodulation signal supplied from said switching circuit is said demodulation signal from said first demodulating circuit.