RADIO-FREQUENCY RECEIVER

• US 20070123186A1
• Filed: 01/25/2007
• Published: 05/31/2007
• Est. Priority Date: 10/14/2003
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakatsuji, Koji, Suzuki, Masanori, Terao, Atsuhito, Asayama, Sanae
• Granted Patent: US 7,418,247 B2
• Time in Patent Office: Days
• US Class Current: 455/188.100
• CPC Class Codes: H03J 3/08 by varying a second parameter simultaneously with the tuning, e.g. coupling bandpass filter
• CPC Class Codes: H03J 5/244 using electronic means
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

A radio-frequency (RF) receiver includes an input terminal for receiving RF signals in a first frequency band and a second frequency band lower than the first frequency band, a first tuned filter allowing a signal of a passing frequency in the RF signal in the first frequency band to pass through the filter, a local oscillator, a frequency divider for frequency-dividing a signal output from the local oscillator, a first mixer operable to convert the signal output from the first tuned filter into a signal of an intermediate frequency, a second tuned filter allowing a signal of a passing frequency of the RF signal in the second frequency band to pass through the filter, a second mixer operable to convert the signal output from the second tuned filter into a signal of the intermediate frequency, and a phase-locked-loop (PLL) circuit operable to control an oscillation frequency of the local oscillator and the passing frequencies of the first tuned filter and the second tuned filter.

Claims

1. A radio-frequency (RF) receiver capable of receiving first RF signals in a first frequency band and second RF signals in a second frequency band lower than the first frequency band, the receiver comprising:

a local oscillator;

a frequency divider for frequency-dividing a signal output from the local oscillator,

wherein the signal output from the frequency divider contains a first output signal and a second output signal different in phase by 90 degrees from the first output signal, the first and second output signal being produced by frequency-dividing the signal output from the local oscillator;

a first signal receiving section for receiving the first RF signals in the first frequency band;

a second signal receiving section for receiving the second RF signals in the second frequency band, the second signal receiving section comprising;

a tuned filter allowing a signal of the second frequency band to pass through the tuned filter,

a first mixer operable to mix the signal output from the tuned filter with the first output signal of the frequency divider,

a phase shifter operable to shift a signal output from the first mixer in phase by 90 degrees, and

a second mixer operable to mix the signal output from the tuned filter with the second output signal of the frequency divider;

wherein a signal output from the second mixer and a signal output from the phase shifter are output from an output terminal of the receiver along with a signal output from the first signal receiving section.