CN1549446A - Automatic gain control circuit and method - Google Patents
Automatic gain control circuit and method Download PDFInfo
- Publication number
- CN1549446A CN1549446A CNA031309909A CN03130990A CN1549446A CN 1549446 A CN1549446 A CN 1549446A CN A031309909 A CNA031309909 A CN A031309909A CN 03130990 A CN03130990 A CN 03130990A CN 1549446 A CN1549446 A CN 1549446A
- Authority
- CN
- China
- Prior art keywords
- gain control
- voltage
- automatic gain
- control circuit
- switch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 10
- 238000001514 detection method Methods 0.000 claims description 5
- 230000006698 induction Effects 0.000 abstract 3
- 230000005540 biological transmission Effects 0.000 description 8
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 240000004859 Gamochaeta purpurea Species 0.000 description 1
- 238000001994 activation Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
Images
Landscapes
- Control Of Amplification And Gain Control (AREA)
Abstract
The invention relates to an automatic gain control circuit and a method applying a time division duplex mode, wherein the automatic gain control circuit comprises an induction circuit, a first switcher, a second switcher, an attenuator, a frequency booster, a comparator and a voltage amplifier. The sensing circuit is used for sensing an input signal. The input end of the attenuator is electrically connected with the first switch. The input end of the frequency booster is electrically connected with the output end of the attenuator, and the output end of the frequency booster is electrically connected with the second switcher. The input end of the comparator receives the output voltage of the induction circuit, and the output end of the comparator is electrically connected with the first switcher and the second switcher for controlling the switching action of the first switcher and the second switcher. The voltage amplifier can amplify the output voltage of the induction circuit to control the attenuation power of the attenuator.
Description
Technical field
The present invention relates to a kind of automatic gain control circuit and method, particularly, relate to a kind of application time division duplex (Time Division Duplexing, TDD) automatic gain control circuit of pattern and method.
Background technology
Along with popularizing gradually of WLAN, not only the demand to the indoor user that gets online without being tethered to a cable with notebook computer increases gradually in each company, and so-called point-to-point or each intercompany of point-to-multipoint pattern or the application of the open airs such as wireless transmission between each building also come into one's own gradually.
Because the wireless transmission common band of the 2.4GHz of ISM has been tending towards saturated state at present, existing those skilled in the art utilize the technological adjustment of lifting frequency to the frequency band that needs to authorize, for example be promoted to the frequency band of 3.5GHz, one is capable of increasing bandwidth, and two can improve the confidentiality of transfer of data.Traditional wireless transmission is that (Frequency Division Duplexing, FDD) pattern, its transfer of data are the continuity pattern to the employing Frequency Division Duplexing (FDD).An automatic gain control circuit 10 of using mode of frequency division duplexing shows the circuit structure of the outdoor unit of a wireless transmitting system that utilizes the lifting frequency technology as shown in Figure 1.This automatic gain control circuit 10 comprises a demodulation multiplexer 11,12, one first intermediate frequency amplifier of attenuator 13, one first frequency mixer 14, one first band pass filter 15, power amplifier 16, transmission oscillator 17, integrator 18,19, low noise amplifier of duplexer (diplexer) 21, image and gets rid of filter 22, one second frequency mixer 23, reception oscillator 24, second band pass filter 25 and one second intermediate frequency amplifier 26, a coupler 27 and a diode 30.This first intermediate frequency amplifier 13, first frequency mixer 14, first band pass filter 15 and power amplifier 16 can be formed a upconverter 28, the input signal of this demodulation multiplexer 11 can be promoted to required frequency, transfer to an antenna 20 via this duplexer 19 again, to carry out wireless transmission.This low noise amplifier 21, image are got rid of filter 22, second frequency mixer 23, second band pass filter 25 and 26 of second intermediate frequency amplifiers and can be formed a frequency demultiplier 29, can reduce the frequency of these antenna 20 received signals, and, information is sent into indoor use via this demodulation multiplexer 11.This diode 30 can detect the induced voltage of this coupler 27, and passes it back this attenuator 12 to adjust its decay power via this integrator 18.Generally speaking, when signal transfers to outdoor unit by indoor unit, because of the difference of build-out will produce about loss of 5 to 15dBm.The transfer of data of mode of frequency division duplexing is successional, so these automatic gain control circuit 10 self-activations are through several seconds to time of tens of seconds and after stable gradually, its final power output can utilize this coupler 27, diode 30 and integrator 18 to carry out FEEDBACK CONTROL, to adjust the decay power of this attenuator 12, thereby be maintained fixing power output, and then improve the unsettled phenomenon of power output that loss causes because of the cable transmission.
Yet, when wireless transmission adopted TDD mode, its information was to transmit with burst mode (burstmode), and the time of transfer of data is different in size, this moment, the power output of this automatic gain control circuit 10 was everlasting when not reaching stable state as yet, just stopped its transfer of data.Thus, not only power output can't be fixed, and output signal may serious distortion.
Summary of the invention
Main purpose of the present invention provides a kind of automatic gain control circuit and method of using TDD mode, cable loss in the time of can reaching outdoor connection indoors according to a wireless transmitting system is adjusted, and makes the signal output of this wireless transmitting system maintain constant power all the time.
Than the employed feedback loop of traditional mode of frequency division duplexing, the automatic gain control circuit of application TDD mode of the present invention and method are to adopt the design of feed-forward loop, before carrying out raising frequency, signal promptly carries out the control of decay power, in order to the time delay of avoiding feedback loop to cause.
The automatic gain control circuit of application TDD mode of the present invention comprises a sensor circuit, first switch, second switch, an attenuator, a upconverter, a comparator and a voltage amplifier.This sensor circuit is used for responding to an input signal.The input of this attenuator is electrically connected with this first switch.The input of this upconverter is electrically connected with the output of this attenuator, and output then is electrically connected with this second switch.The input of this comparator receives the output voltage of this sensor circuit, and its output is electrically connected this first and second switch, in order to control the change action of this first and second switch.This voltage amplifier can amplify the output voltage of this sensor circuit, in order to control the decay power of this attenuator.
The auto gain control method of application TDD mode of the present invention comprises the following step: (1) detects an input signal to produce one first voltage; (2) utilize this first voltage that this input signal is switched to a raising frequency circuit; (3) this first voltage is amplified and one second voltage; (4) utilize this second voltage before this input signal carries out raising frequency, to adjust its decay power.
Description of drawings
The present invention will be illustrated according to accompanying drawing, wherein:
Fig. 1 is the automatic gain control circuit of existing application mode of frequency division duplexing;
Fig. 2 is the automatic gain control circuit of application TDD mode of the present invention;
Fig. 3 detects the input power of diode and the graph of a relation of output voltage;
Fig. 4 is the control voltage of attenuator and the graph of a relation of decay power.
Element numbers explanation among the figure:
50 automatic gain control circuits
51 sensor circuits, 511 couplers, 512 detect diode
52 comparators
53 voltage amplifiers
54 first switchs
55 attenuators
56 upconverters, 561 first intermediate frequency amplifiers, 562 first frequency mixers, 563 first band pass filters, 564 power amplifiers
57 frequency demultipliers, 571 low noise amplifiers, 572 second band pass filters, 573 second frequency mixers, 574 the 3rd band pass filters, 575 second intermediate frequency amplifiers
58 second switchs
59 oscillators
60 cables
Embodiment
Fig. 2 is the automatic gain control circuit 50 of application TDD mode of the present invention, shows the circuit structure of the outdoor unit of a wireless transmitting system that utilizes the lifting frequency technology.This automatic gain control circuit 50 comprises a sensor circuit 51, comparator 52, voltage amplifier 53, one first switch 54, attenuator 55, upconverter 56, one second switch 58, a frequency demultiplier 57 and an oscillator 59.This sensor circuit 51 comprises a coupler 511 and a detection diode 512.This upconverter 56 comprises one first intermediate frequency amplifier 561, one first frequency mixer 562, first band pass filter 563 and a power amplifier 564.This frequency demultiplier 57 comprises a low noise amplifier 571, one second band pass filter 572, one second frequency mixer 573, the 3rd band pass filter 574 and one second intermediate frequency amplifier 575.This oscillator 59 is used to provide radiofrequency signal and carries out mixing for this first frequency mixer 562 and second frequency mixer 573.The main difference of this automatic gain control circuit 50 and prior art is that this sensor circuit 51 is located at the I/O end of signal, when signal is in emission state, this detection diode 512 can detect the induced voltage of this coupler 511, and export one first voltage, this first voltage approximately between 0.2 to 0.8V.This first voltage compares via this comparator 52 and a reference voltage Vcc, thereby produce a control voltage SW CTRL, in order to this first switch 54 and second switch 58 are switched to radiating circuit, promptly this first switch 54, attenuator 55, upconverter 56 and second switch 58 form path.On the contrary, when signal is in accepting state, this first switch 54 and second switch 58 will switch to receiving circuit, promptly form conducting with this frequency demultiplier 57.In addition, this first voltage that detects diode 512 generations will produce one second voltage (for example about 0.6V) after this voltage amplifier 53 amplifies, in order to control the decay power of this attenuator 55, to keep fixing power output.Usually attenuator is to be made by diode, so the control voltage of the input power of this detection diode 512 and output voltage and this attenuator 55 and decay power all are nonlinear positive relationship, it respectively as shown in Figures 3 and 4.Therefore, when this input power that detects diode 512 was hanged down, first voltage of its output was also lower, so that lower through second voltage of these voltage amplifier 53 outputs, so the decay power of this attenuator 55 is less.Otherwise when the input power of this detection diode 512 was higher, this first voltage that detects diode 512 outputs was higher, so that higher through second voltage of these voltage amplifier 53 outputs, so the decay power of this attenuator 55 is more.Thus,, pass through the adjustment of the decay power of this attenuator 55, then can keep fixing power output though the input of this automatic gain control circuit 50 may cause different cable power losss owing to cable is different in size.
Than the feedback loop design of prior art, automatic gain control circuit 50 of the present invention is the notions that adopt feed-forward loop, promptly carries out the adjustment of power before signal enters this upconverter 56.In addition, design of the present invention does not need integrator etc. to cause the assembly of time delay easily in the loop, makes this first switch 54 and second switch 58 more promptly to switch, thereby is fit to very much the burst data transmission of TDD mode.
Technology contents of the present invention and technical characterstic disclose as above, still may be based on teaching of the present invention and announcement and do all replacement and modifications that does not deviate from spirit of the present invention yet be familiar with those skilled in the art.Therefore, protection scope of the present invention should be not limited to the described content of embodiment, and should comprise various do not deviate from replacement of the present invention and modifications, and is contained by the present patent application claim.
Claims (9)
1. an automatic gain control circuit is applied to TDD mode, comprises:
A sensor circuit is used for responding to an input signal;
One first switch is electrically connected with described input signal;
One second switch;
An attenuator, its input is electrically connected with described first switch;
A upconverter, its input is electrically connected with the output of described attenuator, and its output is electrically connected with described second switch;
An amplifier amplifies the output signal of described sensor circuit, is used for controlling the decay power of described attenuator.
2. automatic gain control circuit according to claim 1 is characterized in that described sensor circuit comprises a coupler and a detection diode.
3. automatic gain control circuit according to claim 1, it is characterized in that it further comprises a comparator, its input is used to receive the output signal of described sensor circuit, and its output is used to control the change action of described first and second switch.
4. automatic gain control circuit according to claim 1 is characterized in that described upconverter comprises at least one amplifier, at least one band pass filter and a frequency mixer.
5. automatic gain control circuit according to claim 4 is characterized in that it further comprises an oscillator, is used to provide a radiofrequency signal and carries out mixing for described frequency mixer.
6. automatic gain control circuit according to claim 1 is characterized in that it further comprises a frequency demultiplier, and its two ends are electrically connected to this first and second switch respectively.
7. automatic gain control circuit according to claim 6 is characterized in that described frequency demultiplier comprises at least one amplifier, at least one band pass filter and a frequency mixer.
8. an auto gain control method is applied to TDD mode, comprises the following step:
Detect an input signal to produce one first voltage;
Utilize this first voltage that described input signal is switched to a raising frequency circuit;
Described first voltage amplified and one second voltage;
Utilize described second voltage before this input signal carries out raising frequency, to adjust its decay power.
9. auto gain control method according to claim 8 is characterized in that described first voltage and a predetermined reference voltage compare, to judge whether that this input signal is switched to a raising frequency circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031309909A CN1549446A (en) | 2003-05-12 | 2003-05-12 | Automatic gain control circuit and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA031309909A CN1549446A (en) | 2003-05-12 | 2003-05-12 | Automatic gain control circuit and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1549446A true CN1549446A (en) | 2004-11-24 |
Family
ID=34322749
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA031309909A Pending CN1549446A (en) | 2003-05-12 | 2003-05-12 | Automatic gain control circuit and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1549446A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102315885A (en) * | 2010-06-29 | 2012-01-11 | 原相科技股份有限公司 | Signal strength sensing device, relevant method thereof and communication system |
| CN103067035A (en) * | 2011-10-24 | 2013-04-24 | 联发科技股份有限公司 | Sliced transmitter front-end circuit and related method |
| US9065691B2 (en) | 2011-10-24 | 2015-06-23 | Mediatek Inc. | Sliced transmitter front-end |
-
2003
- 2003-05-12 CN CNA031309909A patent/CN1549446A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102315885A (en) * | 2010-06-29 | 2012-01-11 | 原相科技股份有限公司 | Signal strength sensing device, relevant method thereof and communication system |
| CN102315885B (en) * | 2010-06-29 | 2014-05-07 | 原相科技股份有限公司 | Signal strength sensing device, relevant method thereof and communication system |
| CN103067035A (en) * | 2011-10-24 | 2013-04-24 | 联发科技股份有限公司 | Sliced transmitter front-end circuit and related method |
| US9065691B2 (en) | 2011-10-24 | 2015-06-23 | Mediatek Inc. | Sliced transmitter front-end |
| CN103067035B (en) * | 2011-10-24 | 2015-11-18 | 联发科技股份有限公司 | Sliced transmitter front-end circuits and related methods |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9191903B2 (en) | Remote antenna unit with external power control using a single control line | |
| US5892396A (en) | Method and apparatus for controlling gain of a power amplifier | |
| US10581396B2 (en) | Electric transmission cable module and transmission loss compensation circuit | |
| CN101036309A (en) | Wireless data communication device | |
| EP1764624A2 (en) | Transmitting-receiving module of radar system | |
| CN1549446A (en) | Automatic gain control circuit and method | |
| CN112119598A (en) | Antenna unit, transmission system and method for operating an antenna unit | |
| TWI326526B (en) | Dual band transmitter having filtering coupler | |
| CN210469240U (en) | High-stability forward automatic gain control circuit | |
| CN108598669B (en) | Electronic device | |
| US6542029B1 (en) | Variable-slope variable-gain amplifier | |
| CN1254461A (en) | Power control of RF signals with booster module | |
| JP2000165164A (en) | High frequency amplifier | |
| TWI231646B (en) | Automatic gain control circuit and method | |
| CN113922790B (en) | Group delay tuning-based power synthesis circuit and signal transmission system | |
| CN221828911U (en) | Antenna receiving and transmitting circuit | |
| KR101172035B1 (en) | Low loss duplexer apparatus in time division duplex systems | |
| CN116111959B (en) | power amplifier circuit | |
| CN201127070Y (en) | Digital television receiver | |
| CN219086248U (en) | Antenna assembly and electronic equipment | |
| CN216290845U (en) | L-band 10W power amplifier | |
| US6052031A (en) | Signal level control circuit for amplifiers | |
| CN119135281A (en) | Automatic gain control method and system for pluggable optical module and two-way output peak detection circuit | |
| CN119276392A (en) | Cellular Antenna Compensation Device | |
| KR200270090Y1 (en) | Line-coupler for wireless-repeater |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |