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US 6,320,464 B1Granted
Feedforward amplifier
AssigneeNTT Mobile Communications Network, Inc.
InventorsYasunori Suzuki, Toshio Nojima
Life of this patent
Estimating the term…
Abstract
In a distortion injection path (15) wherein a detected distortion component of a main amplifier (23) becomes amplified, distortion by an auxiliary amplifier (29a) is detected by an auxiliary distortion detector (42) composed of a variable attenuator (27a), a variable phase shifter (28a), a first auxiliary amplifier (29a), a delay line (36) and a phase inverter (37), and the detected distortion is cancelled by an auxiliary distortion canceller (43) composed of a variable attenuator (27b), a variable phase shifter (28a), a second auxiliary amplifier (29b) and a delay line (39), thereby increasing the efficiency of the amplifier.
Claims17
A feedforward amplifier which detects a distortion component of an amplifier output and injects said distortion component into an amplifier output to cancel said distortion component, said feedforward amplifier comprising:
- a main-amplifier distortion detector made up of:
- a main-amplifier path containing a main amplifier, for amplifying and transferring an input signal thereto;
- a first linear path for transferring said input signal linearly;
- a main-amplifier power divider for branching said input signal to said paths;
- and a power combiner/divider for combining the outputs from said main-amplifier path and said first linear path and for outputting the sum component and the difference component of said combined outputs as a main-amplifier main signal component and a main-amplifier distortion component, respectively;
- and
- a main-amplifier distortion canceller made up of:
- a second linear path supplied with said main signal component, for transferring it linearly;
- a main-amplifier distortion injection path containing auxiliary amplifying means, for amplifying and transferring said main-amplifier distortion component;
- and a main-amplifier power combiner for combining the output of said second linear path with the output of said main-amplifier distortion injection path;
- wherein said auxiliary amplifying means comprises:
- an auxiliary-amplifier distortion detector made up of:
- an auxiliary-amplifier power divider for dividing said main-amplifier distortion component into two;
- an auxiliary-amplifier path containing a first auxiliary amplifier, for amplifying and transferring one of said two divided main-amplifier distortion components;
- a third linear path for linearly the other of said two divided main-amplifier distortion components;
- and an auxiliary-amplifier power combiner/divided for combining the outputs of said auxiliary-amplifier path and said third linear path and for outputting the sum component and the difference component of said combined outputs as an auxiliary-amplifier main signal component and an auxiliary-amplifier distortion component, respectively;
- and
- an auxiliary-amplifier distortion canceller made up of:
- a fourth linear path supplied with said auxiliary-amplifier main signal component from said auxiliary-amplifier power combiner/divider, for linearly transferring said auxiliary-amplifier main signal component;
- an auxiliary-amplifier distortion injection path supplied with said auxiliary-amplifier distortion component from said auxiliary-amplifier power combiner/divider, for amplifying and transferring said auxiliary-amplifier distortion component;
- and an auxiliary-amplifier power combiner for combining the outputs of said fourth linear path and said auxiliary-amplifier distortion injection path and for providing said combined output as the output of said main-amplifier injection path to said main-amplifier power combiner.
18 more elements
A feedforward amplifier which detects a distortion component of an amplifier output and injects said distortion component into an amplifier output to cancel said distortion component, said feedforward amplifier comprising:
- a main-amplifier distortion detector made up of:
- a main-amplifier path containing a main amplifier, for amplifying and transferring an input signal thereto;
- a first linear path for transferring said input signal linearly;
- a main-amplifier power divider for branching said input signal to said paths;
- and a power combiner/divider for combining the outputs from said main-amplifier path and said first linear path and for outputting the sum component and the difference component of said combined outputs as a main-amplifier main signal component and a main-amplifier distortion component, respectively;
- and
- a main-amplifier distortion canceller made up of:
- a second linear path supplied with said main signal component, for transferring it linearly;
- a main-amplifier distortion injection path containing auxiliary amplifying means, for amplifying and transferring said main-amplifier distortion component;
- and a main-amplifier power combiner for combining the output of said second linear path with the output of said main-amplifier distortion injection path;
- wherein said main amplifier has a plurality of amplification characteristics;
- and
- wherein said main amplifier comprises:
- a source- or emitter-grounded main-amplifier semiconductor amplifying device for amplifying a signal of said main-amplifier path;
- a main-amplifier voltage converter for changing the voltage to be applied to a drain or collector terminal of said main-amplifier semiconductor amplifying device;
- a main-amplifier detector for detecting an envelope component of a signal to be fed to said main amplifier;
- and a main-amplifier control circuit for controlling said main-amplifier voltage converter in accordance with the output signal of said main-amplifier detector to change the voltage to be applied to said drain or collector terminal of said main-amplifier semiconductor amplifying device to change said amplification characteristic, thereby providing said plurality of amplification characteristics.
14 more elements
A feedforward amplifier which detects a distortion component of an amplifier output and injects said distortion component into an amplifier output to cancel said distortion component, said feedforward amplifier comprising:
- a main-amplifier distortion detector made up of:
- a main-amplifier path containing a main amplifier, for amplifying and transferring an input signal thereto;
- a first linear path for transferring said input signal linearly;
- a main-amplifier power divider for branching said input signal to said paths;
- and a power combiner/divider for combining the outputs from said main- amplifier path and said first linear path and for outputting the sum component and the difference component of said combined outputs as a main-amplifier main signal component and a main-amplifier distortion component, respectively;
- and
- a main-amplifier distortion canceller made up of:
- a second linear path supplied with said main signal component, for transferring it linearly;
- a main-amplifier distortion injection path containing auxiliary amplifying means, for amplifying and transferring said main-amplifier distortion component;
- and a main-amplifier power combiner for combining the output of said second linear path with the output of said main-amplifier distortion injection path;
- wherein said main amplifier has a plurality of amplification characteristics;
- and
- wherein said main amplifier comprises:
- a source- or emitter-grounded main-amplifier semiconductor amplifying device for amplifying a signal of said main-amplifier path;
- a main-amplifier voltage converter for changing the voltage to be applied to a gate or base terminal of said main-amplifier semiconductor amplifying device;
- a main-amplifier detector for detecting an envelope component of a signal to be fed to said main amplifier;
- and a main-amplifier control circuit for controlling said main-amplifier voltage converter in accordance with the output signal of said main-amplifier detector to change the voltage to be applied to said gate or base terminal of said main-amplifier semiconductor amplifying device to change said amplification characteristic, thereby providing said plurality of amplification characteristics.
14 more elements
A feedforward amplifier which detects a distortion component of an amplifier output and injects said distortion component into an amplifier output to cancel said distortion component, said feedforward amplifier comprising:
- a main-amplifier distortion detector made up of:
- a main-amplifier path containing a main amplifier, for amplifying and transferring an input signal thereto;
- a first linear path for transferring said input signal linearly;
- a main-amplifier power divider for branching said input signal to said paths;
- and a power combiner/divider for combining the outputs from said main- amplifier path and said first linear path and for outputting the sum component and the difference component of said combined outputs as a main-amplifier main signal component and a main-amplifier distortion component, respectively;
- and
- a main-amplifier distortion canceller made up of:
- a second linear path supplied with said main signal component, for transferring it linearly;
- a main-amplifier distortion injection path containing auxiliary amplifying means, for amplifying and transferring said main-amplifier distortion component;
- and a main-amplifier power combiner for combining the output of said second linear path with the output of said main-amplifier distortion injection path;
- wherein said main amplifier has a plurality of amplification characteristics;
- and
- wherein said auxiliary amplifying means comprises:
- an auxiliary-amplifier distortion detector made up of:
- an auxiliary-amplifier power divider for dividing said main-amplifier distortion component into two;
- an auxiliary-amplifier path containing a first auxiliary amplifier, for amplifying and transferring one of said two divided main-amplifier distortion components;
- a third linear path for linearly transferring the other of said two divided main-amplifier distortion components;
- and an auxiliary-amplifier power combiner/divider for combining the outputs of said auxiliary-amplifier path and said third linear path and for outputting the sum component and the difference component of said combined outputs as an auxiliary-amplifier main signal component and an auxiliary-amplifier distortion component, respectively;
- and
- an auxiliary-amplifier distortion canceller made up of:
- a fourth linear path supplied with said auxiliary-amplifier main signal component from said auxiliary-amplifier power combiner/divider, for linearly transferring said auxiliary-amplifier main signal component;
- an auxiliary-amplifier distortion injection path supplied with said auxiliary-amplifier distortion component from said auxiliary-amplifier power combiner/divider, for amplifying and transferring said auxiliary-amplifier distortion component;
- and an auxiliary-amplifier power combiner for combining the outputs of said fourth linear path and said auxiliary-amplifier distortion injection path and for providing said combined output as the output of said main-amplifier injection path to said main-amplifier power combiner.
20 more elements
Dependencies are inferred from the claim text.