Radio apparatus

• US 20050042994A1
• Filed: 10/05/2004
• Published: 02/24/2005
• Est. Priority Date: 03/14/1997
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Otaka, Shoji, Kayano, Hiroyuki, Tsurumi, Hiroshi, Sekine, Syuichi, Maeda, Tadahiko, Yoshida, Hiroshi
• Granted Patent: US 7,184,738 B2
• Time in Patent Office: Days
• US Class Current: 455/180.300
• CPC Class Codes: H03D 3/008 Compensating DC offsets
• CPC Class Codes: H03F 1/30 Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in differential amplifiers H03F3/45479
• CPC Class Codes: H03F 2200/294 the amplifier being a low noise amplifier [LNA]
• CPC Class Codes: H03F 2200/372 Noise reduction and elimination in amplifier
• CPC Class Codes: H03F 2200/504 the supply voltage or current being continuously controlled by a controlling signal, e.g. the controlling signal of a transistor implemented as variable resistor in a supply path for, an IC-block showed amplifier
• CPC Class Codes: H03F 3/189 High-frequency amplifiers, e.g. radio frequency amplifiers
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04
• CPC Class Codes: H03L 7/1075 by changing characteristics of the loop filter, e.g. changing the gain, changing the bandwidth H03L7/1072 takes precedence
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04B 1/403 using the same oscillator for generating both the transmitter frequency and the receiver local oscillator frequency
• CPC Class Codes: H04B 1/405 with multiple discrete channels
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a radio apparatus, the band of a loop filter of a synthesizer in a blank channel searching state is narrower than the band in a communicating state. In addition, a radio wave environment is measured. A characteristic necessary for the radio apparatus is determined corresponding to the measured-radio wave environment. The power is controlled corresponding to the performance of the radio apparatus. Thus, the power consumption is decreased. In addition, the efficiency of the output power is improved. In the radio apparatus, the current consumption of a power amplifier PA is measured. A matching circuit (LNA or MIX) of the antenna is adjusted with the measured result so as to decrease an antenna loss. In the radio apparatus, a DC offset is removed from the transmitted power and the reflected wave. When the DC offset is removed using an AC coupling capacitor, the deterioration of the frequency characteristic of the receiving portion is compensated with a capacitor in a digital signal process. In the radio apparatus, a transmission power detecting portion is structured as an IC chip. The transmission power detecting portion detects the transmission power corresponding to leakage currents in the power supply of the IC chip and the ground. Thus, when the power is detected, a power loss is suppressed. Consequently, the power consumption of the radio apparatus can be decreased.

Claims

1-10. -10. (Canceled).

11. A radio apparatus for tandem-connecting structural elements that are at least a frequency converter, a filter, and analog/digital converter through respective capacitors and directly converting the frequency of an RF signal received from an antenna to a baseband signal, comprising:

processing means for adding a digital signal with inverse characteristics of frequency characteristics of the capacitors to a digital signal converted by the analog/digital converter.

12. The radio apparatus as set forth in claim 11,

wherein said processing means comprises:

storing means for storing data of the frequency characteristics of the capacitors; and

means for generating the inverse characteristics corresponding to the data of the frequency characteristics stored in said storing means.

13. The radio apparatus as set forth in claim 11, further comprising:

measuring means for measuring AC coupling frequency characteristics of the capacitors among the structural elements; and

calculating means for calculating the inverse characteristics of the capacitors corresponding to the frequency characteristics measured by said measuring means.

14-24. -24. (Canceled).

25. A radio apparatus for converting a frequency of an RF signal received from an antenna to a baseband signal, the radio apparatus comprising:

a frequency converter configured to convert the RF signal to an analog baseband signal;

a capacitor configured to remove a DC component from the analog baseband signal;

an analog/digital converter configured to convert the analog baseband signal outputted from the frequency converter and through the capacitor into a digital baseband signal; and

a processor unit configured to add a digital signal with an inverse characteristic of a frequency characteristic of the capacitor to the digital baseband signal converted by the analog/digital converter.

26. The radio apparatus as set forth in claim 25,

wherein said processor unit comprises:

a memory unit configured to store a data of the frequency characteristic of the capacitor; and

a generating unit configured to generate the inverse characteristic based on the data of the frequency characteristic stored in said memory unit.

27. The radio apparatus as set forth in claim 25, further comprising:

a measuring unit configured to measure an AC coupling frequency characteristic of the capacitor; and

a calculating unit configured to calculate the inverse characteristic based on the frequency characteristic measured by said measuring unit.