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US 6,552,608 B2Granted
Linear amplifier
AssigneeFujitsu Limited
InventorsAyanori Matsuda, Yutaka Saito
Life of this patent
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Abstract
The present invention relates to a linear amplifier for amplifying power of a radio-frequency signal whose level varies widely, based on feed-forward technique. The linear amplifier according to the present invention is given in advance appropriate transfer characteristics for an error elimination loop and an error detection loop and these appropriate transfer characteristics are applied at a starting time. Therefore, performance and total reliability of equipment to which the present invention is applied are enhanced and cost reduction thereof is realized.
Claims22
A linear amplifier comprising:
- an amplifying section for amplifying a principal signal on which a pilot signal with a known frequency is superimposed, whose linearity is maintained based on feed-forward technique;
- a monitoring section for extracting a component of said pilot signal included as a distortion component at an output end of an error elimination loop which is included in said amplifying section;
- and
- a controlling section to which appropriate transfer characteristics for said error elimination loop and an error detection loop included in said amplifying section are given in advance and which applies the appropriate transfer characteristics at a starting time and updates the transfer characteristics under adaptive control which minimizes a level of the pilot signal extracted by said monitoring section.
1 more element
A linear amplifier comprising:
- an amplifying section for amplifying a principal signal on which a pilot signal with a known frequency is superimposed, whose linearity is maintained based on feed-forward technique;
- a monitoring section for extracting a component of said pilot signal included as a distortion component at an output end of an error elimination loop which is included in said amplifying section;
- and
- a controlling section to which appropriate transfer characteristics for said error elimination loop and an error detection loop included in said amplifying section are given in advance and which applies the appropriate transfer characteristics when a rate of change in a level of the principal signal inputted to said amplifying section or outputted by said amplifying section exceeds a predetermined threshold and updates the transfer characteristics under adaptive control which minimizes a level of the pilot signal which is extracted by said monitoring section.
1 more element
A linear amplifier comprising:
- a pilot signal superimposing section for superimposing a pilot signal with a known frequency on an inputted principal signal;
- an amplifying section
- for amplifying the principal signal on which said pilot signal is superimposed by said pilot signal superimposing section, and
- which maintains linearity based on a feed-forward technique, under adaptive control which minimizes a component of the pilot signal obtained at an output end thereof;
- a level monitoring section for monitoring a level of said inputted principal signal;
- and
- a controlling section for restricting superimposition of the pilot signal done by said pilot signal superimposing section during a period in which the level of the principal signal monitored by said level monitoring section is lower than a predetermined lower limit value.
4 more elements
A linear amplifier comprising:
- a pilot signal superimposing section for superimposing a pilot signal with a known frequency on an inputted principal signal;
- an amplifying section
- for amplifying the principal signal on which said pilot signal is superimposed by said pilot signal superimposing section, and
- which maintains linearity based on a feed-forward technique, under adaptive control which minimizes a component of the pilot signal obtained at an output end thereof;
- and
- a controlling section for restricting, according to a notice indicating a period in which a level of said inputted principal signal is lower than a predetermined lower limit value, superimposition of the pilot signal done by said pilot signal superimposing section during the period.
3 more elements
Dependencies are inferred from the claim text.