US20110006848A1 - Amplifier circuit - Google Patents
Amplifier circuit Download PDFInfo
- Publication number
- US20110006848A1 US20110006848A1 US12/538,249 US53824909A US2011006848A1 US 20110006848 A1 US20110006848 A1 US 20110006848A1 US 53824909 A US53824909 A US 53824909A US 2011006848 A1 US2011006848 A1 US 2011006848A1
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- United States
- Prior art keywords
- transistor
- amplifier
- circuit
- filter circuit
- signals
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- 239000003990 capacitor Substances 0.000 claims description 27
- 238000001914 filtration Methods 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000010897 surface acoustic wave method Methods 0.000 description 3
- 230000000295 complement effect Effects 0.000 description 1
- 230000002079 cooperative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/189—High-frequency amplifiers, e.g. radio frequency amplifiers
- H03F3/19—High-frequency amplifiers, e.g. radio frequency amplifiers with semiconductor devices only
- H03F3/191—Tuned amplifiers
Definitions
- the present disclosure relates to amplifier circuits, and particularly to an amplifier circuit capable of rejecting image signals.
- the communication terminals In wireless communication, when wireless signals are received by communication terminals, the communication terminals often need to convert frequencies of the received signals into working signals capable of being transmitted and processed in the communication terminals. However, the frequency conversion operations may generate image signals interfering with wireless communication. Thus, the communication terminals generally require filters used therein for filtering the image signals.
- the working signals are generally inputted into amplifier circuits to be amplified, and then are transmitted to other functional modules (e.g., decoders or speakers) of the communication terminals to be further processed.
- the filters for filtering image signals are integrated with the amplifier circuits, such that the image signals are filtered before the working signals are further processed.
- SAW surface acoustic wave
- conventional filters integrated with the amplifier circuits, such as the SAW filters are usually expensive, which increases cost of the communication terminals.
- the FIGURE is a circuit diagram of an amplifier circuit, according to an exemplary embodiment.
- an amplifier circuit 100 is provided.
- the amplifier circuit 100 is used in a wireless communication terminal (not shown) such as a mobile phone, a radiogram or an interphone to amplify desired working signals and filter image signals generated in frequency conversion operations.
- the amplifier circuit 100 includes a first amplifier unit 10 , a second amplifier unit 20 and a third amplifier unit 30 connected in series.
- the first amplifier unit 10 includes an input connector 12 , an input filter circuit 14 and a first transistor amplifier module 16 .
- the input connector 12 is electronically connected to other circuits of the communication terminal to input signals.
- the input filter circuit 14 includes a capacitor C 1 and an inductor L 1 .
- the capacitor C 1 has one end connected to the feed connector 12 and another end connected to one end of the inductor L 1 . Another end of the inductor L 1 is connected to the first transistor amplifier module 16 .
- the first transistor amplifier module 16 includes a power supply V 1 , a first transistor M 1 , a resistor R 1 and an inductor L 2 .
- the first transistor M 1 is a Complementary Metal Oxide Semiconductor (CMOS) transistor.
- CMOS Complementary Metal Oxide Semiconductor
- the inductor L 1 has one end connected to the gate of the first transistor M 1 .
- the resistor R 1 has one end connected to the power supply V 1 and another end connected to the gate of the first transistor M 1 .
- the power supply V 1 can provide a working electric potential to the first transistor M 1 through the resistor R 1 .
- the inductor L 2 has one end connected to the source of the first transistor M 1 and another end grounded.
- the drain of the first transistor M 1 is connected to the second amplifier unit 20 to input signals.
- the second amplifier unit 20 includes a second transistor amplifier module 22 , a main filter circuit 24 , a subsidiary filter circuit 26 and a notch-filter 28 .
- the second transistor amplifier module 22 includes a power supply V 2 , a second transistor M 2 , a resistor R 2 and a capacitor C 2 .
- the second transistor M 2 is a CMOS transistor.
- the resistor R 2 has one end connected to the power supply V 2 and another end connected to the gate of the second transistor M 2 .
- the power supply V 2 can provide a working electric potential to the second transistor M 2 through the resistor R 2 .
- the main filter circuit 24 includes a capacitor C 3 and an inductor L 3 , which are connected in parallel between the drain of the first transistor M 1 and the source of the second transistor M 2 .
- the subsidiary filter circuit 26 includes a capacitor C 4 and an inductor L 4 connected in series, wherein the capacitor C 4 has one end connected to the source of the second transistor M 2 and another end connected to the inductor L 4 , and the inductor L 4 has one end connected to the capacitor C 4 and another end grounded.
- the main filter circuit 24 and the source of the second transistor M 2 are both connected to the ground via the subsidiary filter circuit 26 .
- the notch-filter circuit 28 includes two capacitors C 51 , C 52 and two inductors L 51 , L 52 .
- the two capacitors C 51 , C 52 are connected in series between the gate of the second transistor M 2 and one end of the capacitor C 2 .
- the inductor L 51 has one end connected between the capacitors C 51 , C 52 and another end grounded.
- the inductor L 52 has one end connected between the gate of the second transistor M 2 and the capacitor C 51 , and another end connected between the capacitor C 52 and the capacitor C 2 . Another end of the capacitor C 2 is connected to the drain of the first transistor M 1 .
- the drain of the second transistor M 2 is connected to the third amplifier unit 30 to input signals.
- the third amplifier unit 30 includes a third transistor amplifier module 32 , an output filter circuit 34 and an output connector 36 .
- the third transistor amplifier module 32 includes a power supply V 3 , a third transistor M 3 , a resistor R 3 , a capacitor C 6 and an inductor L 6 .
- the third transistor M 3 is a CMOS transistor.
- the resistor R 3 has one end connected to the power supply V 3 and another end connected to the gate of the third transistor M 3 .
- the power supply V 3 can provide a working electric potential to the third transistor M 3 through the resistor R 3 .
- the source of the third transistor M 3 is connected to the drain of the second transistor M 2 .
- the capacitor C 6 has one end connected to the gate of the third transistor M 3 and another end grounded.
- the inductor L 6 has one end connected to the power supply V 3 and another end connected to the drain of the third transistor M 3 .
- the output filter circuit 34 includes three capacitors C 7 , C 8 , C 9 .
- the capacitor C 7 has one end connected between the inductor L 6 and the drain of the third transistor M 3 and another end connected to the capacitor C 8 .
- the capacitor C 8 has one end connected to the capacitor C 7 and another end connected to the output connector 36 .
- the capacitor C 9 has one end connected between the capacitors C 7 , C 8 and another end grounded.
- the amplifier circuit 100 is installed in a wireless communication terminal, e.g., a mobile phone, a radiogram or an interphone.
- the capacitances of the capacitors C 3 , C 4 , C 51 , C 52 and the inductances of the inductors L 3 , L 4 , L 51 , L 52 are regulated to set the resonating frequencies of the input filter circuit 24 , the main filter circuit 26 and the notch-filter circuit 28 .
- An open circuit resonating frequency of the main filter circuit 24 and a resonating frequency of the notch-filter circuit 28 are set to be equal to a same predetermined frequency of the working signals used by the communication terminal.
- a short circuit resonating frequency of the subsidiary filter circuit 26 is set to be equal to a frequency of unneeded signals, e.g., image signals generated in the communication terminal.
- the communication terminal receives wireless communication signals.
- the frequency of the received signals is converted, and the signals are then transformed into working signals to be further processed.
- image signals may be generated.
- the working signals and the image signals both enter the amplifier circuit 100 and are amplified by the first amplifier unit 10 .
- the input filter circuit 10 filters noise signals and the inductor L 2 cooperatives with the first transistor M 1 to form a source feedback to improve amplifying quality.
- the amplified working signals and image signals are both transmitted to the second amplifier unit 20 from the drain of the first transistor M 1 .
- the capacitor C 2 can further filter noise signals.
- the working signals are not able to pass through the main filter circuit 24 , and the notch-filter circuit 28 allows only the working signals to pass through.
- the desired working signals pass through the notch-filter circuit 28 and are inputted into the gate of the second transistor M 2 to be amplified, and the unneeded image signals pass through the main filter circuit 24 and the subsidiary filter circuit 24 to be grounded. In this way, the image signals are filtered.
- the working signals are then transmitted from the drain of the second transistor M 2 to the source of the third transistor M 3 .
- the first transistor amplifier module 16 and the second transistor amplifier module 22 cooperate with the third transistor amplifier module 32 to form a cascade amplifier, which improves quality of the amplified working signals outputted from the output connector 36 .
- the output filter circuit 40 can filter noises in the outputted working signals.
- the amplifier circuit 100 can be widely used in wireless communication terminals. After a communication terminal receives wireless communication signals and converts the frequency of the wireless signals into working signals, the amplifier circuit 100 can both amplify the working signals and filter the image signals generated in the frequency conversion operation. Furthermore, the amplifier circuit 100 can also provide high power plus to the amplified working signals. Understandably, the amplifier circuit 100 can also filter other unneeded signals mixed with the working signals, if only the frequencies of the unneeded signals are different from the frequency of the working signals.
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Abstract
Description
- 1. Technical Field
- The present disclosure relates to amplifier circuits, and particularly to an amplifier circuit capable of rejecting image signals.
- 2. Description of Related Art
- In wireless communication, when wireless signals are received by communication terminals, the communication terminals often need to convert frequencies of the received signals into working signals capable of being transmitted and processed in the communication terminals. However, the frequency conversion operations may generate image signals interfering with wireless communication. Thus, the communication terminals generally require filters used therein for filtering the image signals.
- After the frequency conversion operations, the working signals are generally inputted into amplifier circuits to be amplified, and then are transmitted to other functional modules (e.g., decoders or speakers) of the communication terminals to be further processed. Thus, in most communication terminals, the filters for filtering image signals are integrated with the amplifier circuits, such that the image signals are filtered before the working signals are further processed. For example, surface acoustic wave (SAW) filters are often integrated with amplifier circuits of wireless communication terminals to filter image signals. However, conventional filters integrated with the amplifier circuits, such as the SAW filters, are usually expensive, which increases cost of the communication terminals.
- Therefore, there is room for improvement within the art.
- Many aspects of the present amplifier circuit can be better understood with reference to the following drawing. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present amplifier circuit.
- The FIGURE is a circuit diagram of an amplifier circuit, according to an exemplary embodiment.
- Referring to the FIGURE, an
amplifier circuit 100 according to an exemplary embodiment is provided. Theamplifier circuit 100 is used in a wireless communication terminal (not shown) such as a mobile phone, a radiogram or an interphone to amplify desired working signals and filter image signals generated in frequency conversion operations. Theamplifier circuit 100 includes afirst amplifier unit 10, asecond amplifier unit 20 and athird amplifier unit 30 connected in series. - The
first amplifier unit 10 includes aninput connector 12, aninput filter circuit 14 and a firsttransistor amplifier module 16. Theinput connector 12 is electronically connected to other circuits of the communication terminal to input signals. Theinput filter circuit 14 includes a capacitor C1 and an inductor L1. The capacitor C1 has one end connected to thefeed connector 12 and another end connected to one end of the inductor L1. Another end of the inductor L1 is connected to the firsttransistor amplifier module 16. - The first
transistor amplifier module 16 includes a power supply V1, a first transistor M1, a resistor R1 and an inductor L2. The first transistor M1 is a Complementary Metal Oxide Semiconductor (CMOS) transistor. The inductor L1 has one end connected to the gate of the first transistor M1. The resistor R1 has one end connected to the power supply V1 and another end connected to the gate of the first transistor M1. Thus, the power supply V1 can provide a working electric potential to the first transistor M1 through the resistor R1. The inductor L2 has one end connected to the source of the first transistor M1 and another end grounded. - The drain of the first transistor M1 is connected to the
second amplifier unit 20 to input signals. Thesecond amplifier unit 20 includes a secondtransistor amplifier module 22, amain filter circuit 24, asubsidiary filter circuit 26 and a notch-filter 28. The secondtransistor amplifier module 22 includes a power supply V2, a second transistor M2, a resistor R2 and a capacitor C2. The second transistor M2 is a CMOS transistor. The resistor R2 has one end connected to the power supply V2 and another end connected to the gate of the second transistor M2. Thus, the power supply V2 can provide a working electric potential to the second transistor M2 through the resistor R2. Themain filter circuit 24 includes a capacitor C3 and an inductor L3, which are connected in parallel between the drain of the first transistor M1 and the source of the second transistor M2. Thesubsidiary filter circuit 26 includes a capacitor C4 and an inductor L4 connected in series, wherein the capacitor C4 has one end connected to the source of the second transistor M2 and another end connected to the inductor L4, and the inductor L4 has one end connected to the capacitor C4 and another end grounded. Thus, themain filter circuit 24 and the source of the second transistor M2 are both connected to the ground via thesubsidiary filter circuit 26. - The notch-
filter circuit 28 includes two capacitors C51, C52 and two inductors L51, L52. The two capacitors C51, C52 are connected in series between the gate of the second transistor M2 and one end of the capacitor C2. The inductor L51 has one end connected between the capacitors C51, C52 and another end grounded. The inductor L52 has one end connected between the gate of the second transistor M2 and the capacitor C51, and another end connected between the capacitor C52 and the capacitor C2. Another end of the capacitor C2 is connected to the drain of the first transistor M1. - The drain of the second transistor M2 is connected to the
third amplifier unit 30 to input signals. Thethird amplifier unit 30 includes a thirdtransistor amplifier module 32, anoutput filter circuit 34 and anoutput connector 36. The thirdtransistor amplifier module 32 includes a power supply V3, a third transistor M3, a resistor R3, a capacitor C6 and an inductor L6. The third transistor M3 is a CMOS transistor. The resistor R3 has one end connected to the power supply V3 and another end connected to the gate of the third transistor M3. Thus, the power supply V3 can provide a working electric potential to the third transistor M3 through the resistor R3. The source of the third transistor M3 is connected to the drain of the second transistor M2. The capacitor C6 has one end connected to the gate of the third transistor M3 and another end grounded. The inductor L6 has one end connected to the power supply V3 and another end connected to the drain of the third transistor M3. - The
output filter circuit 34 includes three capacitors C7, C8, C9. The capacitor C7 has one end connected between the inductor L6 and the drain of the third transistor M3 and another end connected to the capacitor C8. The capacitor C8 has one end connected to the capacitor C7 and another end connected to theoutput connector 36. The capacitor C9 has one end connected between the capacitors C7, C8 and another end grounded. - The
amplifier circuit 100 is installed in a wireless communication terminal, e.g., a mobile phone, a radiogram or an interphone. The capacitances of the capacitors C3, C4, C51, C52 and the inductances of the inductors L3, L4, L51, L52 are regulated to set the resonating frequencies of theinput filter circuit 24, themain filter circuit 26 and the notch-filter circuit 28. An open circuit resonating frequency of themain filter circuit 24 and a resonating frequency of the notch-filter circuit 28 are set to be equal to a same predetermined frequency of the working signals used by the communication terminal. A short circuit resonating frequency of thesubsidiary filter circuit 26 is set to be equal to a frequency of unneeded signals, e.g., image signals generated in the communication terminal. - In use, the communication terminal receives wireless communication signals. The frequency of the received signals is converted, and the signals are then transformed into working signals to be further processed. In the frequency conversion operation, image signals may be generated. The working signals and the image signals both enter the
amplifier circuit 100 and are amplified by thefirst amplifier unit 10. Theinput filter circuit 10 filters noise signals and the inductor L2 cooperatives with the first transistor M1 to form a source feedback to improve amplifying quality. - The amplified working signals and image signals are both transmitted to the
second amplifier unit 20 from the drain of the first transistor M1. The capacitor C2 can further filter noise signals. According to above-mentioned frequency characteristics of themain filter circuit 24, thethird filter 26 and the notch-filter circuit 28, the working signals are not able to pass through themain filter circuit 24, and the notch-filter circuit 28 allows only the working signals to pass through. Thus, the desired working signals pass through the notch-filter circuit 28 and are inputted into the gate of the second transistor M2 to be amplified, and the unneeded image signals pass through themain filter circuit 24 and thesubsidiary filter circuit 24 to be grounded. In this way, the image signals are filtered. - The working signals are then transmitted from the drain of the second transistor M2 to the source of the third transistor M3. Thus, the first
transistor amplifier module 16 and the secondtransistor amplifier module 22 cooperate with the thirdtransistor amplifier module 32 to form a cascade amplifier, which improves quality of the amplified working signals outputted from theoutput connector 36. The output filter circuit 40 can filter noises in the outputted working signals. - The
amplifier circuit 100 can be widely used in wireless communication terminals. After a communication terminal receives wireless communication signals and converts the frequency of the wireless signals into working signals, theamplifier circuit 100 can both amplify the working signals and filter the image signals generated in the frequency conversion operation. Furthermore, theamplifier circuit 100 can also provide high power plus to the amplified working signals. Understandably, theamplifier circuit 100 can also filter other unneeded signals mixed with the working signals, if only the frequencies of the unneeded signals are different from the frequency of the working signals. - It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of structures and functions of various embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Claims (18)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
TW98123372 | 2009-07-10 | ||
TW98123372A | 2009-07-10 | ||
TW098123372A TWI483542B (en) | 2009-07-10 | 2009-07-10 | Amplifier circuit |
Publications (2)
Publication Number | Publication Date |
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US7855605B1 US7855605B1 (en) | 2010-12-21 |
US20110006848A1 true US20110006848A1 (en) | 2011-01-13 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US12/538,249 Expired - Fee Related US7855605B1 (en) | 2009-07-10 | 2009-08-10 | Amplifier circuit |
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US (1) | US7855605B1 (en) |
TW (1) | TWI483542B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN117713706A (en) * | 2024-02-06 | 2024-03-15 | 深圳飞骧科技股份有限公司 | Low-noise amplifier and radio frequency chip |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8373508B2 (en) * | 2008-12-24 | 2013-02-12 | Nxp B.V. | Power amplifier |
US20150056940A1 (en) * | 2013-08-23 | 2015-02-26 | Qualcomm Incorporated | Harmonic trap for common gate amplifier |
JP2021182713A (en) * | 2020-05-20 | 2021-11-25 | 住友電気工業株式会社 | Power amplification circuit |
Citations (7)
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US6681103B1 (en) * | 2000-08-25 | 2004-01-20 | Sige Semiconductor Inc. | On-chip image reject filter |
US7221924B2 (en) * | 2003-04-30 | 2007-05-22 | Agency For Science, Technology And Research | Wideband monolithic tunable high-Q notch filter for image rejection in RF application |
US7266360B2 (en) * | 2004-04-07 | 2007-09-04 | Neoreach, Inc. | Low noise amplifier for wireless communications |
US20080204148A1 (en) * | 2007-02-23 | 2008-08-28 | Qualcomm Incorporated | Amplifier with integrated filter |
US7522024B2 (en) * | 2007-04-06 | 2009-04-21 | Mediatek Inc. | Negative gm circuit, a filter and low noise amplifier including such a filter |
US7629850B2 (en) * | 2007-07-13 | 2009-12-08 | International Busines Machines Corporation | Variable-gain image-reject low-noise amplifier |
US7636021B2 (en) * | 2005-05-20 | 2009-12-22 | Synergy Microwave Corporation | Low noise and low phase hits tunable oscillator |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8077795B2 (en) * | 2005-10-03 | 2011-12-13 | Telefonaktiebolaget Lm Ericsson (Publ) | Apparatus and method for interference mitigation |
US8306494B2 (en) * | 2008-08-14 | 2012-11-06 | Broadcom Corporation | Method and system for a single-ended input low noise amplifier with differential output |
-
2009
- 2009-07-10 TW TW098123372A patent/TWI483542B/en not_active IP Right Cessation
- 2009-08-10 US US12/538,249 patent/US7855605B1/en not_active Expired - Fee Related
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6681103B1 (en) * | 2000-08-25 | 2004-01-20 | Sige Semiconductor Inc. | On-chip image reject filter |
US7221924B2 (en) * | 2003-04-30 | 2007-05-22 | Agency For Science, Technology And Research | Wideband monolithic tunable high-Q notch filter for image rejection in RF application |
US7266360B2 (en) * | 2004-04-07 | 2007-09-04 | Neoreach, Inc. | Low noise amplifier for wireless communications |
US7636021B2 (en) * | 2005-05-20 | 2009-12-22 | Synergy Microwave Corporation | Low noise and low phase hits tunable oscillator |
US20080204148A1 (en) * | 2007-02-23 | 2008-08-28 | Qualcomm Incorporated | Amplifier with integrated filter |
US7522024B2 (en) * | 2007-04-06 | 2009-04-21 | Mediatek Inc. | Negative gm circuit, a filter and low noise amplifier including such a filter |
US7629850B2 (en) * | 2007-07-13 | 2009-12-08 | International Busines Machines Corporation | Variable-gain image-reject low-noise amplifier |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN117713706A (en) * | 2024-02-06 | 2024-03-15 | 深圳飞骧科技股份有限公司 | Low-noise amplifier and radio frequency chip |
Also Published As
Publication number | Publication date |
---|---|
US7855605B1 (en) | 2010-12-21 |
TW201103254A (en) | 2011-01-16 |
TWI483542B (en) | 2015-05-01 |
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