Wireless handset

• US 6,466,774 B1
• Filed: 09/18/2000
• Issued: 10/15/2002
• Est. Priority Date: 07/21/1998
• Status: Expired due to Fees

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takei, Ken, Okabe, Hiroshi
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Vuong, Quochien B.
• Application Number:
  US09/663,206
• Time in Patent Office: 757 Days
• Field of Search: 455/193.1, 455/226.1, 455/226.2, 455/193.2, 455/193.3, 455/69, 455/150.1, 455/161.1, 455/161.2, 455/161.3, 455/179.1, 455/71, 455/277.2, 455/575, 455/280, 455/281, 455/282, 455/287, 455/289, 455/129, 455/121, 333/32, 343/860, 343/702
• US Class Current: 455/150.1
• CPC Class Codes: H01Q 1/243 with built-in antennas

Abstract

A novel wireless handset is provided which can provide control so as to tune a center frequency of impedance matching of a tunable antenna to a call frequency.

A first control signal sent from the central processing unit 51 to the synthesizer 41 or data used in the central processing unit to generate the first control signal is used to generate a second control signal by the central processing unit or the control signal generator 52 provided in the outside connected with the central processing unit, and the second control signal is applied to the control circuit 30 for center frequency of impedance matching, whereby center frequencies of impedance matching of the tunable antenna 10 are controlled.

Claims

1. A wireless handset used in a communication system that switches a plurality of call frequencies for use, comprising:

a tunable antenna having a circuit for center frequency of impedance matching;

a strength detector for retaining received signal strength for each call frequency;

a circuit that refers to a frequency to voltage conversion table retaining a relationship between a digital signal for controlling a DC voltage value for setting a center frequency of impedance matching of said tunable antenna and each call frequency, to output a digital signal corresponding to information about a call frequency indicating an input maximum received signal strength; and

a digital to analog converter for generating a DC voltage for setting a center frequency of impedance matching of the tunable antenna in accordance with said digital signal, wherein control is performed by said DC voltage so that a center frequency of impedance matching of the tunable antenna tunes to a call frequency.