Radio signal reception with a PLL frequency controlled for an IF signal depending on coexistence of a spurious signal with the radio signal
First Claim
1. A radio signal receiving method of receiving a radio signal, comprising the steps of generating a phase locked oscillation signal of a generated frequency, frequency multiplying said phase locked oscillation signal into a local oscillation signal with said generated frequency multiplied into a local oscillation frequency with a multiplication factor, mixing said radio signal end said local oscillation signal into an intermediate frequency signal, and receiving said intermediate frequency signal to produce an information signal carried by said radio signal, wherein:
- said generating step is a controllable generating step of generating said phase locked oscillation signal with a controllable frequency;
said frequency multiplying step is a controllable frequency multiplying step of multiplying said controllable frequency into said local oscillation frequency with a controllable factor used as said multiplication factor;
said receiving step comprising the steps of;
detecting, responsive to said intermediate frequency signal, whether or not a spurious signal coexists with said radio signal; and
controlling said controllable generating step and said controllable frequency multiplying step to raise said controllable frequency and to reduce said controllable factor when coexistence of said spurious signal is detected.
1 Assignment
0 Petitions
Accused Products
Abstract
In a radio receiver a PLL oscillator generates a phase locked oscillation signal with a controllable frequency and a frequency multiplier multiplies the controllable frequency with a controllable factor into a local oscillation frequency to provide a local oscillation signal for mixing into an IF signal with a radio signal reaching the receiver, the IF signal is monitored to raise the controllable frequency and to reduce the controllable factor when a spurious signal coexists with the radio signal. This coexistence is detected by monitoring a level difference between the IF signal and an output signal of an IF filter. Preferably, the oscillator comprises in a PLL two VCO'"'"'s for generating phase locked oscillation signals of higher and lower oscillation frequencies, such as 260 and 65 MHz, and a controllable prescaler supplied with high and low voltage signals when the VCO'"'"'s are put in operation at the higher and the lower oscillation frequencies. Concurrently, the controllable factor is controlled to factors of unity and four.
-
Citations
20 Claims
-
1. A radio signal receiving method of receiving a radio signal, comprising the steps of generating a phase locked oscillation signal of a generated frequency, frequency multiplying said phase locked oscillation signal into a local oscillation signal with said generated frequency multiplied into a local oscillation frequency with a multiplication factor, mixing said radio signal end said local oscillation signal into an intermediate frequency signal, and receiving said intermediate frequency signal to produce an information signal carried by said radio signal, wherein:
-
said generating step is a controllable generating step of generating said phase locked oscillation signal with a controllable frequency; said frequency multiplying step is a controllable frequency multiplying step of multiplying said controllable frequency into said local oscillation frequency with a controllable factor used as said multiplication factor; said receiving step comprising the steps of; detecting, responsive to said intermediate frequency signal, whether or not a spurious signal coexists with said radio signal; and controlling said controllable generating step and said controllable frequency multiplying step to raise said controllable frequency and to reduce said controllable factor when coexistence of said spurious signal is detected. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A radio receiver for receiving a radio signal, comprising phase locked oscillator means for generating a phase locked oscillation signal of a generated frequency, frequency multiplier means for frequency multiplying said phase locked oscillation signal into a local oscillation signal with said generated frequency multiplied into a local oscillation frequency with a multiplication factor, mixer means for mixing said radio signal and said local oscillation signal into an intermediate frequency signal, and receiver means for receiving said intermediate frequency signal to produce an information signal carried by said radio signal, wherein:
-
said phase locked oscillator means is controllable phase locked oscillator means for generating said phase locked oscillation signal with a controllable frequency used as said generated frequency; said frequency multiplier means is controllable frequency multiplier means for multiplying said controllable frequency into said local oscillation frequency with a controllable factor used as said multiplication factor; said receiver means comprising; detector means responsive to said intermediate frequency signal for detecting whether or not a spurious signal coexists with said radio signal; and control means for controlling said controllable phase locked oscillator means and said controllable frequency multiplier means to raise said controllable frequency and to reduce said controllable factor when coexistence of said spurious signal is detected. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A combination of a local oscillator and intermediate frequency filter circuitry used in a radio receiver comprising phase locked oscillator means for generating a phase locked oscillation signal of a generated frequency, frequency multiplier means for frequency multiplying said phase locked oscillation signal into a local oscillation signal with said generated frequency multiplied into a local oscillation frequency with a multiplication factor to be operable as said local oscillator in cooperation with said phase locked oscillator means, and mixer means for producing an intermediate frequency signal of an intermediate frequency by mixing said local oscillation signal and a radio signal reaching said radio receiver, said intermediate frequency filter circuitry comprising an intermediate frequency bandpass filter for filtering said intermediate frequency signal into a filtered signal and demodulator means for demodulating said filtered signal into an information signal carried by said radio signal, wherein:
-
said phase locked oscillator means is controllable phase locked oscillator means for generating said phase locked oscillation signal with a controllable frequency used as said generated frequency; said frequency multiplier means is controllable frequency multiplier means for multiplying said controllable frequency into said local oscillation frequency with a controllable factor used as said multiplication factor; said intermediate frequency filter circuitry further comprising; detector means for detecting a level difference between said intermediate frequency signal and said filtered signal to produce a level difference signal indicative of whether or not a spurious signal coexists with said radio signal; and control means for controlling said controllable phase locked oscillator means and said controllable frequency multiplier means to raise said controllable frequency and to reduce said controllable factor when coexistence of said spurious signal is detected. - View Dependent Claims (16, 17, 18, 19, 20)
-
Specification