High frequency apparatus

• US 20050227662A1
• Filed: 03/17/2005
• Published: 10/13/2005
• Est. Priority Date: 04/13/2004
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Umeda, Takashi, Adachi, Kenji
• Granted Patent: US 7,359,691 B2
• Time in Patent Office: Days
• US Class Current: 455/283
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

Disclosed is a high frequency apparatus which eliminates an influence of interfering signals. An interference-cut filter (24) for eliminating interfering signals is disposed between an input terminal (22) and a mixer (27). The interference-cut filter (24) is so controlled that it effectively demonstrates the function while the interfering signals are transmitted. Control of the interference-cut filter (24) is made by a switch (23), which is controlled by a selector switch controller (39), and the switch controller (39) is controlled responsive to an error correction counter (38) and a radio wave transmitted from a cellular telephone (40). This structure eliminates interference attributable to communication signals transmitted by the cellular telephone (40) and undesirable signals entering from the outside. The invention can thus realize high quality reception.

Claims

1. A high frequency apparatus comprising:

an input terminal for receiving a high frequency signal;

a mixer having an input port for receiving the signal fed through the input terminal, and another input port in connection to an output of a local oscillator;

an output terminal for delivering an output of the mixer; and

an interference-cut filter disposed between the input terminal and the mixer for removing an interfering signal included in the high frequency signal,

wherein the interference-cut filter is controlled when an interfering signal is transmitted.

2. The high frequency apparatus of claim 1 for receiving a high frequency digital signal from the input terminal,

the high frequency apparatus further comprising a demodulator and an error correction circuit disposed in this order between the mixer and the output terminal,

wherein the interference-cut filter is controlled when a value of error correction signal output by the error correction circuit exceeds a predetermined value.

3. The high frequency apparatus of claim 1 further comprising a cellular telephone mounted thereto, wherein

an interference frequency of the interference-cut filter is set to match with a transmission frequency of the cellular telephone, and

the interference-cut filter is controlled at least when a radio wave is transmitted from the cellular telephone.

4. The high frequency apparatus of claim 2 further comprising an AGC voltage detector circuit in connection to an output of the mixer,

wherein the interference-cut filter is controlled when an output of the AGC voltage detector circuit is within a predetermined voltage range.

5. The high frequency apparatus of claim 1 further comprising an interference-pass filter connected to the input terminal for passing an interfering signal of same frequency as the interference-cut filter, and an interference signal detector in connection to an output of the interference-pass filter, wherein

the interference-cut filter is controlled when an output of the interference signal detector exceeds a predetermined value.

6. The high frequency apparatus of claim 5, wherein center frequencies of the interference-cut filter and the interference-pass filter are made variable continuously in a synchronized manner.