CN101594124B - A coordinate tunable filter and a wireless communication front end circuit - Google Patents
A coordinate tunable filter and a wireless communication front end circuit Download PDFInfo
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- CN101594124B CN101594124B CN2009100033220A CN200910003322A CN101594124B CN 101594124 B CN101594124 B CN 101594124B CN 2009100033220 A CN2009100033220 A CN 2009100033220A CN 200910003322 A CN200910003322 A CN 200910003322A CN 101594124 B CN101594124 B CN 101594124B
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Abstract
The invention discloses a front end circuit with coordinate tunable filter, wherein the circuit comprises a first filter, an amplifier and a second filter; the amplifier is coupled to the first filter; the second filter is coupled to the amplifier; the amplifier is arranged between the first and the second filter; the first filter is provided with an adjustable first center frequency for filtering the received signal; the amplifier is used for outputting the first filter; the second filter is provided with an adjustable second center frequency for filtering the output of the amplifier, wherein, the first and the second center frequency is provided with an adjusting relationship of coordination.
Description
Technical field
The present invention relates to a kind of filter apparatus and use the wireless communication front end circuit of this filter, and particularly relate to a kind of wireless communication front end circuit that has the coordinate tunable filter apparatus and use this filter.
Background technology
At present development of wireless communication devices let people amenities of life great facility, the user can be out of doors or the indoor mobile device of borrowing just can surf the Net or communicate etc. with the people.Yet, in whole wireless channel, be flooded with the signal of various different frequencies; When the user will communicate with radio receiving terminal equipment; Must launch the signal of the frequency that is assigned to, and must do reception to the signal of the frequency that is assigned to when receiving, correctly transceive data.
At wireless communication front end circuit, generally all possessed prefilter, with postfilter.Prefilter is generally done filtering in order to the input signal to low noise amplifier, and rearmounted filter then is the action of the output signal of low noise amplifier being done filtering.Yet traditional wireless communication front end circuit has the function of selecting multi-frequency multi-mode, with the situation in the face of various different communication modes and frequency selection.But traditional wireless communication front end circuit is then because need to integrate many group filters, and makes and more caused the waste of power outside cost and the area increase of hardware.
Please with reference to Fig. 1, Fig. 1 shows the circuit diagram of traditional wireless communication front-end circuit 10.This wireless communication front end circuit 10 is US 6,345,176 B1 patents that Ericsson company obtained in 2002.This wireless communication front end circuit comprises antenna 100, low noise amplifier circuit 11, the linear amplifying circuit 12 of low current, control circuit 108, selector 109, local oscillator (local oscillator) 110 and intermediate frequency (intermediate frequency) amplifier 107.
Low noise amplifier circuit 11 comprises low noise amplifier 101, low-noise mixer 102 and low noise intermediate frequency amplifier 103.Wherein, low-noise mixer 102 is coupled to low noise amplifier 101 and low noise intermediate frequency amplifier 103.The linear amplifying circuit 12 of low current comprises the linear amplifier 104 of low current, linear frequency mixer 105 of low current and the linear intermediate frequency amplifier 106 of low current.Wherein, the linear frequency mixer 105 of low current is coupled to linear amplifier 104 of low current and the linear intermediate frequency amplifier 106 of low current.
Please with reference to Fig. 2, Fig. 2 shows the circuit diagram of the traditional wireless communication front end circuit 20 of another kind.This wireless communication front end circuit 20 is US 4,225,823 B1 patents that Nippon Gakki Seizo Kabushiki Kausha company obtained in 1980, and this wireless communication front end circuit 20 is applied to the receiver of FM (Frequency Modulation).This wireless communication front end circuit 20 comprises first front-end circuit 21, second front-end circuit 22, local oscillator 23, selector 24 and 25.Selector 24 is coupled to first front-end circuit 21 and second front-end circuit 22.Frequency mixer 23 is coupled to first front-end circuit 21 and second front-end circuit 22.Selector 25 is coupled to first front-end circuit 21 and second front-end circuit 22.
First front-end circuit 21 comprises coil 210,214, high frequency filter 211,213, amplifier 212 and frequency mixer 215.Wherein, coil 210 is coupled to selector 24.Amplifier 212 is coupled to high frequency filter 211 and 213.Coil 214 is coupled to frequency mixer 215.Frequency mixer 215 is coupled to selector 25 and local oscillator 23.Second front-end circuit 22 comprises high frequency filter 220,222, amplifier 221 and frequency mixer 223.Wherein, high frequency filter 220 is coupled to selector 24.Amplifier 221 is coupled to high frequency filter 220 and 222.High frequency filter 222 is coupled to frequency mixer 223.Frequency mixer 223 is coupled to selector 25 and local oscillator 23.
The filter 211,213,220 and 222 of this wireless communication front end circuit 20 has the Q value (Q factor) of different qualities; This wireless communication front end circuit 20 is by first and second control signal control selector 24 and 25; Choose first front-end circuit 21 or second front-end circuit 22 for output, to reach optimum signal noise ratio (signal-to-noise ratio) according to the intensity of signal and interference signal.Yet this wireless communication front end circuit 20 needs many group filters, so cost is higher, hardware area and consumed power are bigger.
Please with reference to Fig. 3, Fig. 3 shows the circuit diagram of another traditional wireless communication front end circuit 30.This wireless communication front end circuit 30 is 5,437, No. 051 patent of US that Toshiba company obtained in nineteen ninety-five.This wireless communication front end circuit 30 comprises demultiplexer 31, low frequency front-end circuit 32, high frequency front-end circuit 33, local oscillator 34, selector 35a, 35b, first intermediate frequency amplifier 36, intermediate-frequency filter 37, second intermediate frequency amplifier 38 and demodulator 39.
Demultiplexer 31 is coupled to low frequency front-end circuit 32 and high frequency front-end circuit 33.Local oscillator 34 is coupled to low frequency front-end circuit 32 and high frequency front-end circuit 33.Selector 35a is coupled to low frequency front-end circuit 32 and high frequency front-end circuit 33.First intermediate frequency amplifier 36 is coupled to selector 35a.Intermediate-frequency filter 37 is coupled to first intermediate frequency amplifier 36.Second intermediate frequency amplifier 38 is coupled to intermediate-frequency filter 37.Demodulator 39 is coupled to second intermediate frequency amplifier 38.Selector 35b is coupled to demodulator 39.
Low frequency front-end circuit 32 comprises first low frequency amplifier 320, first attenuator 321, second low frequency amplifier 322, low-frequency filter 323, frequency mixer 324 and buffer amplifier 325.Wherein, first low frequency amplifier 320 is coupled to demultiplexer 31.First attenuator 321 is coupled to first low frequency amplifier 320.Second low frequency amplifier 322 is coupled to first attenuator 321.Low-frequency filter 323 is coupled to second low frequency amplifier 322.Frequency mixer 324 is coupled to selector 35a, buffer amplifier 325 and low-frequency filter 323.Buffer amplifier 325 is coupled to local oscillator 34.
High frequency front-end circuit 33 comprises first high-frequency amplifier 320, second attenuator 331, second high-frequency amplifier 332, high frequency filter 333, frequency mixer 334 and buffer amplifier 335.Wherein, first high-frequency amplifier 330 is coupled to demultiplexer 31.Second attenuator 331 is coupled to first high-frequency amplifier 330.Second high-frequency amplifier 332 is coupled to second attenuator 331.High frequency filter 333 is coupled to second high-frequency amplifier 332.Frequency mixer 334 is coupled to selector 35a, buffer amplifier 335 and high frequency filter 333.Buffer amplifier 335 is coupled to local oscillator 34.
Demultiplexer 31 is divided into low frequency signal and high-frequency signal with the signal input_sig that receives, and low frequency signal is delivered to low frequency front-end circuit 32, and high-frequency signal then is sent to high frequency front-end circuit 33.First and second attenuator 321,331 can be with noise attentuation.Selector 35a and 35b are controlled by first control signal and second control signal respectively.The restituted signal 39a and the 39b of two kinds of opposed polarities of demodulator 39 outputs, its polarity is relevant with selector 35a selection high frequency front-end circuit 33 or low frequency front-end circuit 32.
This wireless communication front end circuit 30 selects the output of output or low frequency signal of high-frequency signal to reach the function of selecting frequency signal by first control signal control selector 35a.Yet this wireless communication front end circuit 30 needs many group filters and amplifier, so cost is higher, hardware area is big, consumed power is big and hardware complexity is higher.
In addition; The US 7 that SiGe Semiconductor company was obtained in 2007; 187, No. 913 patent provides a kind of wireless communication front end circuit, and this front-end circuit has filter array; And come the control filters array by control interface, make this front-end circuit can to the action chosen of the frequency band that will receive.Yet the area of this filter array, cost and consumed power are all big, and do not meet the trend of the compact and power saving of present communications electronics.
Comprehensive the above, traditional wireless communication front end circuit has that hardware complexity is higher, chip area and the bigger problem of consumed power, does not meet the trend of the compact and power saving of present communications electronics product.Therefore, in order to reduce chip area, consumed power, manufacturing cost and hardware complexity, the present invention provides a kind of wireless communication front end circuit employed coordinate tunable filter of wireless communication front end circuit therewith.
Summary of the invention
The present invention is providing a kind of front-end circuit with harmony tunable filter, and the manufacturing cost of this front-end circuit tradition is cheap, and all more traditional front-end circuit of consumed power, hardware complexity and chip area is little.
The present invention provides a kind of filter apparatus that is applicable to wireless communication front end circuit again, adopts the wireless communication front end circuit of this filter apparatus to have advantages such as low manufacturing cost, low consumpting power, low hardware area and low hardware complexity.
The present invention provides a kind of front-end circuit with harmony tunable filter again, and this front-end circuit only uses a transistor AND gate variable resistor and electric capacity, and it is with low cost, consumed power is little, hardware complexity is low and chip area is little.
The present invention proposes a kind of front-end circuit with harmony tunable filter, and this circuit comprises first filter, amplifier and second filter.Amplifier is coupled to first filter, and second filter is coupled to amplifier, and amplifier is between first and second filter.First filter has adjustable first centre frequency, in order to carry out filtering to received signal.Amplifier is in order to amplify the output of first filter.Second filter has adjustable second centre frequency, carries out filtering in order to the output of pair amplifier.Wherein, first and second centre frequency has the adjusting relation (coherent-tuning) of harmony.First, second filter and amplifier are integrated circuits, and this integrated circuit comprises input, output, earth terminal, transistor, variable capacitance and variable inductance.Transistor is coupled to input, output and earth terminal.Variable capacitance is coupled to output, and variable inductance also is coupled to output.Wherein, transistor has parasitic capacitance, and this parasitic capacitance is between input and output.
According to the described front-end circuit of another embodiment of the present invention with harmony tunable filter; First, second above-mentioned filter and amplifier are integrated circuits, and this integrated circuit comprises input, output, earth terminal, transistor, feedback resistance, feedback capacity, variable capacitance and variable inductance.Transistor is coupled to input, output and earth terminal.Feedback resistance is coupled between output and the input.Feedback capacity is coupled between output and the input.Variable capacitance is coupled to output.Variable inductance is coupled to output.Wherein, feedback resistance and feedback capacity are one another in series.
The present invention provides a kind of front-end circuit with harmony tunable filter, and this front-end circuit comprises input, output, earth terminal, transistor, variable capacitance and variable inductance.Transistor is coupled to input, output and earth terminal.Variable capacitance is coupled to output, and variable inductance also is coupled to output.Wherein, transistor has parasitic capacitance, and parasitic capacitance is between input and output, and parasitic capacitance and transistor form first filter at input, and variable capacitance, variable inductance and transistor form second filter at output.First and second filter has adjustable first centre frequency and second centre frequency respectively, and first has the adjusting relation of harmony with this second centre frequency.
According to embodiments of the invention, the above-mentioned front-end circuit with harmony tunable filter also comprises feedback resistance and feedback capacity.Feedback resistance is coupled between input and the output.Feedback capacity is coupled between input and the output.Wherein, Feedback capacity, feedback resistance and transistor form first filter at input; Variable capacitance, variable inductance and transistor form second filter at output; First and second filter has adjustable first centre frequency and second centre frequency respectively, and first has the adjusting relation of harmony with this second centre frequency.
First and second filter that the present invention has the adjusting relation of harmony because of employing, the described front-end circuit of the embodiment of the invention and filter apparatus just can reach unlike the filter of quite a few groups of traditional front-end circuit and filter apparatus needs and amplifier and be applied on the communicating by letter of multi-frequency multi-mode.So this front-end circuit and filter apparatus have low consumpting power, low manufacturing cost, chip area is little and the low advantage of hardware complexity.
For let above and other objects of the present invention, feature and advantage can be more obviously understandable, hereinafter is special lifts embodiment, and conjunction with figs., elaborates as follows.
Description of drawings
Fig. 1 shows the circuit diagram of traditional wireless communication front-end circuit 10.
Fig. 2 shows the circuit diagram of the traditional wireless communication front end circuit 20 of another kind.
Fig. 3 shows the circuit diagram of another traditional wireless communication front end circuit 30.
Fig. 4 shows the circuit diagram of one embodiment of the invention.
Fig. 5 a shows the circuit diagram of the integrated circuit 50 of prefilter 41, amplifier 42 and post amplifier 43.
Fig. 5 b and Fig. 5 c show the circuit diagram of variable inductance LL respectively.
Fig. 5 d shows the circuit diagram of another kind of integrated circuit 60.
Fig. 5 e shows the circuit diagram of another integrated circuit 70.
Fig. 5 f shows the circuit diagram of another kind of integrated circuit 90.
Fig. 5 g shows the circuit diagram of another integrated circuit 99.
Fig. 5 h shows the circuit diagram of another integrated circuit 95.
Fig. 6 shows the reflection coefficient of the above embodiments and the curve chart of gain coefficient.
The reference numeral explanation
10: wireless communication front end circuit
100: antenna
11: low noise amplifier circuit
12: the linear amplifying circuit of low current
108: control circuit
109: selector
110: local oscillator
107: intermediate frequency amplifier
101: low noise amplifier
102: low-noise mixer
103: the low noise intermediate frequency amplifier
104: the linear amplifier of low current
105: the linear frequency mixer of low current
106: the linear intermediate frequency amplifier of low current
20: wireless communication front end circuit
21: the first front-end circuits
22: the second front-end circuits
23: local oscillator
24,25: selector
210,214: coil
211,213: high frequency filter
212: amplifier
215: frequency mixer
220,222: high frequency filter
221: amplifier
223: frequency mixer
30: wireless communication front end circuit
31: demultiplexer
32: the low frequency front-end circuit
33: the high frequency front-end circuit
34: local oscillator
35a, 35b: selector
36: the first intermediate frequency amplifiers
37: intermediate-frequency filter
38: the second intermediate frequency amplifiers
39: demodulator
320: the first low frequency amplifiers
321: the first attenuators
322: the second low frequency amplifiers
323: low-frequency filter
324: frequency mixer
325: buffer amplifier
320: the first high-frequency amplifiers
331: the second attenuators
332: the second high-frequency amplifiers
333: high frequency filter
334: frequency mixer
335: buffer amplifier
40: front-end circuit
41: prefilter
42: amplifier
43: postfilter
44: frequency mixer
50,60,70: integrated circuit
501: input
502: output
503: earth terminal
560: selector
M1, M2:N type field-effect transistor
CF: feedback resistance
RF: feedback capacity
CL: variable capacitance
LL: variable inductance
Cgd: parasitic capacitance
L1～Ln, LG: inductance
Bipolar junction transistor of BJT1:NPN
LD: inductance
80～83: curve.
Embodiment
In order to solve the problem of traditional wireless communication front-end circuit hardware complexity, area and manufacturing cost, embodiments of the invention provide a kind of front-end circuit with harmony tunable filter.The hardware complexity of this front-end circuit, area and manufacturing cost are all come lowly than the conventional wireless front-end circuit.
Please with reference to Fig. 4, Fig. 4 shows the circuit diagram of one embodiment of the invention.This front-end circuit 40 comprises prefilter 41, amplifier 42 and postfilter 43.Amplifier 42 is coupled to prefilter 41, and postfilter 43 is coupled to amplifier 42, and amplifier 42 is between prefilter 41 and postfilter 43.Prefilter 41 has adjustable first centre frequency, in order to carry out filtering to received signal.Amplifier 42 is in order to amplify the output of prefilter 41.Postfilter 43 has adjustable second centre frequency, carries out filtering in order to the output of pair amplifier 42.Wherein, first and second centre frequency has the adjusting relation (coherent-tuning) of harmony.
This front-end circuit 40 also comprises frequency mixer 44, and frequency mixer 44 is coupled to postfilter 43, carries out smear in order to the output to postfilter 43.In this embodiment, first centre frequency equals second centre frequency, regulates relation because first and second centre frequency has harmony, so by adjustment second centre frequency, first centre frequency also can be followed and adjusted.In addition, in this embodiment, amplifier 42 can be low noise amplifier or general amplifier.
When first and second centre frequency be adjusted to receive frequency the time, the interference signal that prefilter 41 can other frequencies of filtering, linearity degree of requirement that therefore can step-down amplifier 42.Postfilter 43 carries out filtering with the output of amplifier 42 again, just can reduce the linearity degree of requirement of frequency mixer 44.This front-end circuit 40 goes for the wireless communication system of number of different types; Only need first and second centre frequency is adjusted to the frequency that institute's desire receives; Just can reach a plurality of wireless communication systems and share the purpose of front-end circuit 40, therefore can reduce hardware complexity, chip area and production cost significantly.
Prefilter 41 in the above-mentioned front-end circuit 40, amplifier 42 can use an integrated circuit to implement with post amplifier 43.Please with reference to Fig. 5 a, Fig. 5 a shows the circuit diagram of the integrated circuit 50 of prefilter 41, amplifier 42 and post amplifier 43.This integrated circuit 50 comprises input 501, output 502, earth terminal 503, n type field effect transistor (N-type MOS transistor) M1, feedback resistance CF, feedback capacity RF, variable capacitance CL and variable inductance LL.Transistor M1 is coupled to input 501, output 502 and earth terminal 503.Feedback resistance RF is coupled between output 502 and the input 501.Feedback capacity CF is coupled between output 502 and the input 501.Variable capacitance CL is coupled to output 502, and variable inductance LL also is coupled to output 502.Wherein, feedback resistance RF and feedback capacity CF are one another in series.
In this embodiment, the drain electrode end of transistor M1 (drain end) is coupled to output 502, and the source terminal of transistor M1 (source end) is coupled to earth terminal 503, and the gate terminal of transistor M1 (gate end) is coupled to input 501.Yet n type field effect transistor M1 is not in order to limit the present invention.
The transistor M1 of this integrated circuit 50 is in order to as commonsource amplifier; Feedback resistance RF, feedback capacity CF and transistor M1 form prefilter 41 at input 501, and variable inductance LL, variable capacitance CL and transistor M1 form postfilter 43 at output.Because variable inductance LL and variable capacitance CL can adjust, therefore, postfilter 43 is actually the adjustable band pass filter of second centre frequency.The impedance of feedback capacity CF, feedback resistance RF and input 501 (generally speaking being 50 ohm) can receive the influence of impedance, variable inductance LL and the variable capacitance CL of output 502; So first centre frequency of prefilter 41 can be adjusted along with second centre frequency, therefore first centre frequency and second centre frequency have the adjusting relation of a harmony.Likewise, the impedance of output 502, variable inductance LL and variable capacitance CL can receive the influence of impedance, feedback capacity CF and the feedback resistance RF of input 501.
When the frequency that receives signal reaches formed second centre frequency of variable inductance LL and variable capacitance CL; The load impedance of output 502 is a pure real number; This moment, the reflection coefficient of input 501 was minimum in first centre frequency; Make signal can get into transistor M1, and because the adjusting relation of above-mentioned harmony, first centre frequency equals second centre frequency.And when the frequency that receives signal during away from this second centre frequency, reflection coefficient can be because the impedance that input 501 is seen becomes away from 50 ohm greatly, and makes input signal can't get into transistor M1.So feedback capacity CF, feedback resistance RF and transistor M1 can form prefilter 41 at input 501.
Because the impedance of input 501, feedback capacity CF and feedback resistance RF can interact with impedance, variable inductance LL and the variable capacitance CL of output 502, so first centre frequency and second centre frequency have the adjusting relation of a harmony.That is to say that the reflection coefficient (reflected signal is to the ratio of input signal) of input 501 and the gain coefficient of output 502 (the output signal is to the ratio of input signal) also have the adjusting relation of harmony; When the frequency of input signal equals first centre frequency and second centre frequency; Reflection coefficient is minimum, and gain coefficient is maximum.
Please with reference to Fig. 5 b and Fig. 5 c, Fig. 5 b and Fig. 5 c show the circuit diagram of variable inductance LL respectively.Among Fig. 5 b, variable inductance LL comprises selector 560 and a plurality of inductance L 1～Ln.Selector 560 is controlled by control signal control_sig, to select needed inductance value by this.Among Fig. 5 c, variable inductance LL comprises inductance L G and selector 560, has a plurality of contacts by inductance L G, and control signal control_sig control selector 560 is selected the contact of inductance L G, to select needed inductance value by this.
Please with reference to Fig. 5 d, Fig. 5 d shows the circuit diagram of another kind of integrated circuit 60.This integrated circuit 60 is not have feedback resistance RF and feedback capacity CF with integrated circuit 50 different places, is utilize the parasitic capacitance Cgd of transistor M1 between input 501 and output 503 to be used as feedback capacity.Therefore, parasitic capacitance Cgd and transistor M1 can form prefilter 41 at input 501.Variable capacitance CL, variable inductance LL and transistor M1 then form postfilter 43 at output 503.The operating principle of integrated circuit 60 is identical with the operating principle of integrated circuit 50, does not therefore give unnecessary details at this.
Please with reference to Fig. 5 e～5h, Fig. 5 e shows the circuit diagram of another integrated circuit 70; Fig. 5 f shows the circuit diagram of another kind of integrated circuit 90; And Fig. 5 g shows the circuit diagram of another integrated circuit 99; Fig. 5 h shows the circuit diagram of another kind of integrated circuit 95.This integrated circuit 70 is to use bipolar junction transistor BJT1 of NPN (NPN BJT transistor) to replace n type field effect transistor M1 with integrated circuit 50 different places.Wherein, the collector terminal of transistor BJT1 (collector end) is coupled to output, and the emitter terminal of this transistor BJT1 (emitter end) is coupled to earth terminal, and the base terminal of this transistor BJT1 (base end) is coupled to input.Integrated circuit 90 adds inductance L D between earth terminal 503 and transistor M1, in order to improve the input impedance matching of integrated circuit 90, obtain preferable noise figure (Noise Figure), and the linearity can be raised also.99 of integrated circuits are the embodiment that resistance R F is removed, and integrated circuit 70,90 is identical with the operating principle of integrated circuit 50 with 99, therefore also do not give unnecessary details at this.Integrated circuit 95 then is between feedback capacity CF and transistor M1, to couple a transistor M2; The grid of transistor M2 receives bias voltage Vb; Its operating principle is same as described above; Also do not give unnecessary details at this, its inductance L D is then equally not essential in addition, and the transistor M2 among this embodiment is a n type field effect transistor.
Then, please with reference to Fig. 6, Fig. 6 shows the reflection coefficient of the above embodiments and the curve chart of gain coefficient.As shown in Figure 6, when first centre frequency and second centre frequency were 2.709GHz, gain coefficient curve 80 can reach 17.41dB at 2.709GHz, and reflection coefficient curve 81 then has minimum value at 2.709GHz.When first centre frequency and second centre frequency were 3.528GHz, gain coefficient curve 82 can reach 18.52dB at 3.528GHz, and reflection coefficient curve 83 then has minimum value at 3.528GHz.By Fig. 6, can see that first centre frequency and second centre frequency have the adjusting relation of above-mentioned harmony.
In sum, at embodiments of the invention a kind of front-end circuit and a kind of filter apparatus that is applicable to front-end circuit are provided, this front-end circuit and filter apparatus have low manufacturing cost, advantages such as low hardware complexity, low consumpting power and little hardware area.In addition, as noted earlier, the front-end circuit that the embodiment of the invention provides can be applied on the communication system of multi-frequency multi-mode.
Though the present invention discloses as above with embodiment; Right its is not in order to limiting the present invention, anyly has the knack of this art, do not breaking away from the spirit and scope of the present invention; When can doing a little change and retouching, so protection scope of the present invention is as the criterion when looking the claim person of defining of the present invention.
Claims (19)
1. the front-end circuit with harmony tunable filter is characterized in that, comprising:
One first filter has adjustable one first centre frequency, carries out filtering in order to receive signal to one;
One amplifier is coupled to this first filter, in order to amplify the output of this first filter; And
One second filter is coupled to this amplifier, has adjustable one second centre frequency, carries out filtering in order to the output to this amplifier;
Wherein, this amplifier this first and this second filter between, this first has the adjusting relation of a harmony with this second centre frequency;
Wherein, this first, second filter and this amplifier are integrated circuits, and this integrated circuit comprises:
One input, an output and an earth terminal;
One the first transistor is coupled to this input, this output and this earth terminal;
One variable capacitance is coupled to this output; And
One variable inductance is coupled to this output;
Wherein, this first transistor has a parasitic capacitance, and this parasitic capacitance is between this input and this output.
2. the front-end circuit with harmony tunable filter as claimed in claim 1 is characterized in that, also comprises:
One frequency mixer is coupled to this second filter, in order to the output frequency reducing to this second filter.
3. the front-end circuit with harmony tunable filter as claimed in claim 1; It is characterized in that wherein, this first centre frequency equals this second centre frequency; The adjusting relation of this harmony is meant that this first centre frequency also and then is conditioned when regulating this second centre frequency.
4. the front-end circuit with harmony tunable filter as claimed in claim 1 is characterized in that, wherein, this amplifier is a low noise amplifier.
5. the front-end circuit with harmony tunable filter as claimed in claim 1 is characterized in that, wherein, this integrated circuit also comprises:
One feedback capacity is coupled between this output and this input.
6. the front-end circuit with harmony tunable filter as claimed in claim 5 is characterized in that, wherein, this integrated circuit also comprises:
One feedback resistance is coupled between this output and this input, and wherein, this feedback resistance and this feedback capacity are one another in series.
7. the front-end circuit with harmony tunable filter as claimed in claim 1 is characterized in that, wherein, this integrated circuit also comprises:
One transistor seconds is coupled between this output and this first transistor, and its grid receives a bias voltage.
8. the front-end circuit with harmony tunable filter as claimed in claim 1, wherein, this integrated circuit also comprises:
One inductance is coupled between this first transistor and this earth terminal.
9. the front-end circuit with harmony tunable filter is characterized in that, comprising:
One input, an output and an earth terminal;
One the first transistor is coupled to this input, this output and this earth terminal;
One variable capacitance is coupled to this output; And
One variable inductance is coupled to this output;
Wherein, This first transistor has a parasitic capacitance; This parasitic capacitance is between this output and this input, and this parasitic capacitance and this first transistor form one first filter at this input, and this variable capacitance, this variable inductance and this first transistor form one second filter at this output; This first and second filter has adjustable one first centre frequency and one second centre frequency respectively, and this first has the adjusting relation of a harmony with this second centre frequency.
10. the front-end circuit with harmony tunable filter as claimed in claim 9; It is characterized in that wherein, this first centre frequency equals this second centre frequency; The adjusting relation of this harmony is meant that this first centre frequency also and then is conditioned when regulating this second centre frequency.
11. the front-end circuit with harmony tunable filter as claimed in claim 9 is characterized in that, wherein, this front-end circuit with harmony tunable filter also comprises:
One feedback capacity is coupled between this output and this input;
Wherein, This feedback capacity and this first transistor form one first filter at this input; This variable capacitance, this variable inductance and this first transistor form one second filter at this output; This first and second filter has adjustable one first centre frequency and one second centre frequency respectively, and this first has the adjusting relation of a harmony with this second centre frequency.
12. the front-end circuit with harmony tunable filter as claimed in claim 11 is characterized in that, wherein, this front-end circuit with harmony tunable filter also comprises:
One feedback resistance is coupled between this output and this input;
Wherein, This feedback capacity, this feedback resistance and this first transistor form one first filter at this input; This variable capacitance, this variable inductance and this first transistor form one second filter at this output; This first and second filter has adjustable one first centre frequency and one second centre frequency respectively, and this first has the adjusting relation of a harmony with this second centre frequency.
13. the front-end circuit with harmony tunable filter as claimed in claim 9 is characterized in that, wherein, this first transistor forms an amplifier.
14. the front-end circuit with harmony tunable filter as claimed in claim 13 is characterized in that, this amplifier is a low noise amplifier.
15. the front-end circuit with harmony tunable filter as claimed in claim 9 is characterized in that, wherein, this front-end circuit with harmony tunable filter also comprises:
One frequency mixer is coupled to this second filter, in order to the output frequency reducing to this second filter.
16. the front-end circuit with harmony tunable filter as claimed in claim 9; It is characterized in that; This first transistor is a n type field effect transistor, and the drain electrode end of this n type field effect transistor is coupled to this output, and the source terminal of this n type field effect transistor is coupled to this earth terminal or is coupled to an end of an inductor; The other end of this inductor is coupled to earth terminal, and the gate terminal of this n type field effect transistor is coupled to this input.
17. the front-end circuit with harmony tunable filter as claimed in claim 9; It is characterized in that; This first transistor is bipolar junction transistor of a NPN, and the collector terminal of bipolar junction transistor of this NPN is coupled to this output, and the emitter-base bandgap grading end of bipolar junction transistor of this NPN is coupled to this earth terminal or is coupled to an end of an inductor; The other end of this inductor is coupled to earth terminal, and the base terminal of bipolar junction transistor of this NPN is coupled to this input.
18. the front-end circuit with harmony tunable filter as claimed in claim 9 is characterized in that, wherein, this front-end circuit with harmony tunable filter also comprises:
One transistor seconds is coupled between this output and this first transistor, and its grid receives a bias voltage.
19. the front-end circuit with harmony tunable filter as claimed in claim 18 is characterized in that, wherein, this transistor seconds is a n type field effect transistor, and its source electrode is coupled to this output, and its drain electrode is coupled to this first transistor.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US12/126,941 US8073419B2 (en) | 2007-12-28 | 2008-05-26 | Coherent tunable filter apparatus and wireless communication front-end circuit thereof |
| US12/126,941 | 2008-05-26 |
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|---|---|
| CN101594124A CN101594124A (en) | 2009-12-02 |
| CN101594124B true CN101594124B (en) | 2012-05-16 |
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| CN2009100033220A Expired - Fee Related CN101594124B (en) | 2008-05-26 | 2009-01-22 | A coordinate tunable filter and a wireless communication front end circuit |
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| CN101917758B (en) * | 2010-07-23 | 2014-12-10 | 中兴通讯股份有限公司 | High-power wireless front end and application method thereof |
| AU2016405599B2 (en) * | 2016-05-02 | 2019-06-20 | Telefonaktiebolaget Lm Ericsson (Publ) | Amplifier |
| CN116942169B (en) * | 2023-09-21 | 2024-02-02 | 之江实验室 | Miniaturized brain-computer signal amplifier and brain-computer interface chip system |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1953338A (en) * | 2005-10-20 | 2007-04-25 | 三星电子株式会社 | Wireless receiving device without pll frequency synthesizer and wireless receiving method using the same |
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2009
- 2009-01-22 CN CN2009100033220A patent/CN101594124B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1953338A (en) * | 2005-10-20 | 2007-04-25 | 三星电子株式会社 | Wireless receiving device without pll frequency synthesizer and wireless receiving method using the same |
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| CN101594124A (en) | 2009-12-02 |
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