Radio transmitter and radio communication method

• US 6,519,293 B1
• Filed: 12/09/1999
• Issued: 02/11/2003
• Est. Priority Date: 06/03/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Miyake, Atsushi
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): AL BESHRAWI, TONY
• Application Number:
  US09/445,364
• Time in Patent Office: 1,160 Days
• Field of Search: 375/297, 375/296, 455/126, 330/127
• US Class Current: 375/297
• CPC Class Codes: H03G 3/3047 for intermittent signals, e.g. burst signals
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A radio transmitter in which a power level of a modulated signal that has been amplified by an amplifier is detected, an error component is detected by comparing the detected power level with a theoretical value, an ideal value is calculated by adding the error component to the theoretical value, a reference level is generated by comparing the ideal value with the error component, and the gain of the amplifier is controlled based on a difference between the detected power level and the generated reference level.

Claims

1. A radio transmitter comprising:

amplifier means for amplifying a modulated signal;

detection means for detecting a power level of said modulated signal amplified by said amplifier means, and for detecting an error component by comparing said power level with a theoretical value;

arithmetic means for calculating an ideal value by adding an error component in said error component detected by said detection means to said theoretical value;

generation means for generating a reference level by comparing said ideal value calculated by said arithmetic means with said error component detected by said detection means; and

control means for controlling a gain of said amplifier means based on a difference between said power level detected by said detection means and said reference level generated by said generation means.

3. A radio transmitter according to claim 1, further comprises calculation means for calculating said theoretical value that indicates a burst waveform by using a window function.

5. A radio transmitter according to claim 1, further comprises calculation means for calculating an envelope curve value based on a base-band signal, for calculating an error component by comparing said envelope curve value at a reference time with a specified power value, and for calculating an ideal value by adding said error component to said envelope curve value at each time.

7. A radio transmitter according to claim 1, wherein said detection means comprises a first subtracter for subtracting said power level from said theoretical value and for outputting said error component, and said generation means comprises a second subtracter for subtracting said error component outputted by said first subtracter from said ideal value obtained by said arithmetic means and for outputting said reference level.

8. A radio transmitter according to claim 7, wherein said arithmetic means comprises an adder for adding said error component at said reference time to said theoretical value and for outputting said ideal value.

9. A radio transmitter according to claim 8, wherein said arithmetic means further comprises a sample and hold circuit for storing said error component at said reference time when receiving a timing signal, and for outputting said error component to said adder.

2. A radio transmitter comprising:

first amplifier means for amplifying a modulated signal;

second amplifier means for amplifying said modulated signal that has been amplified by said first amplifier means;

detection means for detecting a power level of said modulated signal amplified by said second amplifier means, and for detecting an error component by comparing said power level with a theoretical value;

first control means for controlling a gain of said first amplifier means based on said error component detected by said detection means; and

second control means for controlling a gain of said second amplifier means based on a difference between said power level detected by said detection means and a reference level.

4. A radio transmitter according to claim 2, further comprises calculation means for calculating said theoretical value that indicates a burst waveform by using a window function.

6. A radio transmitter according to claim 2, further comprises calculation means for calculating an envelope curve value based on a base-band signal, for calculating an error component by comparing said envelope curve value at a reference time with a specified power value, and for calculating an ideal value by adding said error component to said envelope curve value at each time.

10. A radio transmission method comprising the steps of:

detecting a power level of a modulated signal when an amplifier amplifies said modulated signal, and detecting an error component by comparing said power level with a theoretical value;

calculating an ideal value by an arithmetic operation in which an error component in said error component and said theoretical value are added;

generating a reference level by comparing said ideal value with said error component; and

controlling a gain of said amplifier means based on a difference between said power level and said reference level.

12. A radio transmission method according to claim 10, wherein an ideal value indicating a burst waveform is calculated based on a window function.

14. A radio transmission method according to claim 10, wherein an envelope curve value is calculated based on a base-band signal, an error component is calculated by comparing said envelope curve value at a reference time with a specified power value, and an ideal value is calculated by adding said error component to said envelope curve value at each time.

11. A radio transmission method, comprising the steps of:

detecting a power level of a modulated signal and then detecting an error component by comparing said power level with a theoretical value when a first amplifier amplifies said modulated signal and a second amplifier then amplifies said modulated signal;

controlling a gain of said first amplifier based on said error component; and

controlling a gain of said second amplifier based on a difference between said power level and a reference level.

13. A radio transmission method according to claim 11, wherein an ideal value indicating a burst waveform is calculated based on a window function.

15. A radio transmission method according to claim 11, wherein an envelope curve value is calculated based on a base-band signal, an error component is calculated by comparing said envelope curve value at a reference time with a specified power value, and an ideal value is calculated by adding said error component to said envelope curve value at each time.