CN1553588A - Self-adaptation balancing apparatus for SDH transmission system circuit attenuation compensation - Google Patents
Self-adaptation balancing apparatus for SDH transmission system circuit attenuation compensation Download PDFInfo
- Publication number
- CN1553588A CN1553588A CNA03131824XA CN03131824A CN1553588A CN 1553588 A CN1553588 A CN 1553588A CN A03131824X A CNA03131824X A CN A03131824XA CN 03131824 A CN03131824 A CN 03131824A CN 1553588 A CN1553588 A CN 1553588A
- Authority
- CN
- China
- Prior art keywords
- circuit
- signal
- gain
- control circuit
- amplitude
- 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.)
- Granted
Links
Images
Landscapes
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
This invention is relative to a self-adaptive automatic equalizer used to compensate line attenuation for SDH transmission system, specially is used to compensate the E1 line attenuation for the self-adaptive equalizer. It comprises the automatic gain control circuit, the pre-filtering circuit, the gain lifting circuit, the post filtering circuit, the amplitude detection circuit and digital control circuit, the comparison circuit and the clock time extraction circuit. This invention has wide automatic equalization range reaching from several meters to several kilometers, the self-adaptive automatic equalizer can self adapt the amplitude and phase characteristics to the length of the transmission line, thus whether the transmission distance of the signal is long and short they all can be equalized accurately and properly.
Description
Technical field
The present invention relates to the adaptive equalization device of a kind of SDH of being used for transmission system Line Attenuation compensation, particularly relate to a kind ofly in the SDH transmission system, be used for the adaptive equalization device of E1 Line Attenuation compensation.
Background technology
In communication transmission system, if the signal transmission surpasses certain distance, signal transfer quality will be difficult to guarantee, so Line Attenuation is to influence the effectively key factor of transmission of E1 signal.
Because the distortion of signal that transmission line causes is usually expressed as: the one, the wave-shape amplitude of the signal that receives diminishes, and this causes owing to there is decay in transmission line; The 2nd, crest is delayed, and this is because the time-delay characteristics of transmission line cause; The 3rd, pulse duration increases greatly, and this is because the frequency characteristic of transmission line causes.
In order to realize that signal correctly and accurately transmits, we need use equalizer that the signal of distortion and decay is carried out equilibrium in the E1 interface circuit.Described equalizer is positioned at the front end of E1 receiver, and its particular location as shown in Figure 1.
Equalizer is actual to be a kind of compensating circuit, and it produces the characteristic opposite with the characteristic of channel, offsets fading channel, thereby realizes the compensation to the frequency characteristic and the phase characteristic of input signal.Fig. 2 is transmission-line attenuation amplitude, equalizer enlargement range and complete attenuation characteristic and E1 signal frequency graph of relation, and Fig. 3 is the attenuation characteristic curve of different transmission lines.
By Fig. 2 and Fig. 3 as can be known, the effect of equalizer is to amplify and filtering, and different transmission ranges needs equalizer to have different equalization characteristics.Such as long line transmission, equalizer need amplify at front end, when short-term is used, because the decay of high frequency is little, so the equalizer high frequency compensation is very little.
Data in a lot of at present communications all transmit by transmission line, signal transmission distance is often from tens meters to several kilometers, the transmission line of different length has different characteristic curves, uncertain transmission range produces signal attenuation in various degree, how to guarantee that it is a very important problem that signal integrity is exported without distortion through different transmission lines, thereby the design of equalizer is had higher requirement.
Usually the method for the equalizer that adopts has:
The first, peak value detection type equalizer, this circuit is made up of the passive equalization network, network has fixedly limit and variable zero, the position at zero point is relevant with the transmission distance, the length of transmission range will cause the variation of electric current on the diode in the equalizing network, the change of electric current is big or diminish and cause the diode equivalent changes in resistance, thereby change the dead-center position of equalizer, but the balanced scope of this equalizer is smaller, sees patent 3568100 (Automatic equalizer for digitaltransmission systems) for details.
The second, adopt all variable equalizer in position of pole and zero, peak detection circuit is used for producing the door that voltage control signal drives FFT, forms nonlinear resistance and produces zero point and limit.The advantage of this method is to be easy to realize, sees patent 4,887 for details, 278 (Equalizer fordigital transmission systems), but adjusting range also is very limited.
Above-mentioned two kinds of existing equalizers all can't be implemented in the very interior circuit automatic equalization of wide region, in case the scope that this equalizer institute can equilibrium is longer than or is shorter than to input signals distance, then equilibrium and balanced excessively situation will appear owing in input signal after this equalizer output, therefore can't reach desirable portfolio effect.
Summary of the invention
The technical problem to be solved in the present invention is the shortcoming that can't make corresponding adjustment according to the actual transmissions distance neatly for the equalizer that overcomes prior art, a kind of adaptive equalization device that is used for the compensation of SDH transmission system Line Attenuation is proposed, can balanced distance be 0 to 1500 meter, can maximum equalizing signal decay to-signal of 43db.
The present invention is achieved in that
A kind of adaptive equalization device that is used for the compensation of SDH transmission system Line Attenuation, it is characterized in that this device is by automatic gain control circuit, the pre-filtering circuit, amplitude detection circuit, digital control circuit, feedback control loop and gain improvement circuit that comparison circuit and clock timing extraction circuit are formed, the post-filtering circuit is formed;
Automatic gain control circuit is used for the signal of input is carried out equilibrium on the amplitude, no matter make the signal amplitude of outside input is what, just in time is decay value behind the 17db of normal signal through the amplitude of signal behind the automatic gain control circuit;
The pre-filtering circuit is used for removing the decay of self-channel to carrying out filtering through the outside E1 signal after the automatic gain control circuit equilibrium, adopts traditional RC filter to realize;
Gain improvement circuit is used for waveform to distortion and carries out compensation on the phase place, adopts switched-capacitor circuit to realize;
The post-filtering circuit is used for the signal after promoting through balanced, gain is carried out filtering, the switching noise that the filtering gain improvement circuit produces;
Amplitude detection circuit by five comparative levels are set, is used to transmit the judgement of line length;
Digital control circuit according to the result that amplitude detection circuit detects, is exported correct control signal and is given automatic gain control circuit and gain improvement circuit, is used to adjust gain and phase place after the automatic gain control circuit equilibrium;
Comparison circuit, the analog signal that is used for being exported through the automatic gain control circuit equilibrium changes into digital signal;
The clock timing extraction circuit, be used for extracting clock from the signal that preposition filter circuit is exported, the rising edge of this clock is just in time in the central authorities of data, this clock is as the clock of digital control circuit, correctly detect the state of amplitude detection circuit output level, give digital control circuit thereby obtain more correct result;
Described gain improvement circuit begins to be initial condition, automatic gain control circuit begins the gain-state for 0db, data are decayed by five set comparative levels difference respective signal of amplitude detection circuit through different transmission-line attenuations, obtain the digital signal of a more rough sign transmission attenuation situation, on correct sequential, detect the amplitude detection signal by digital control circuit, and the signal of amplitude detection judged and export control signal and give automatic gain control circuit, change the attenuation/gain value of automatic gain control circuit, the result of automatic gain control circuit adjustment is the amplitude stabilization that makes output back signal, be the 17db of normal signal attenuation amplitude promptly through the signal behind the automatic gain control circuit, after the loop stability, the automatic gain control circuit digital control signal will truly reflect the attenuation of external transmission lines, after the transmission line distance is determined, digital control circuit just can be exported one group of control signal according to transmission range and give gain improvement circuit, by changing the amplitude and the phase characteristic of gain improvement circuit, reach the automatic equalization and the compensation of amplitude and phase place.
Described automatic gain control circuit is made up of two programmable amplifiers, provides the set of number control signal by digital control circuit to automatic gain control circuit, with ride gain and decay;
The variation each time of described digital controlled signal, automatic gain control circuit removes the signal that amplifies or decay and import with the factor that each step-length 1.7db adjusts gain or decay;
After the amplitude of whole loop reached the value of normal signal decay 17db, gain and decay factor were maintained fixed.
Described pre-filtering circuit, it is a second-order low-pass filter, form unlimited gain multichannel feedback low pass filter by resistance-capacitance network and high-gain amplifier, from the output of amplifier to being provided with a plurality of negative feedbacks the end of oppisite phase, be that output signal is passed through resistance or directly arrived input by capacitive feedback, the long-pending upper limit much larger than filter bandwidht of bandwidth of operational amplifiers gain in the described filter adopts the output of both-end input both-end, and inner amplifier adopts common-mode feedback;
Under high frequency, electric capacity is equivalent to short circuit, and transfer function is 0, and under low frequency, electric capacity is equivalent to open circuit;
Described pre-filtering circuit provides a precipitous frequency decay, the noise of filtering external input signal and interference, and the signal that limits other frequency enters gain improvement circuit, obtains the E1 signal of useful frequency.
Described gain improvement circuit is made up of switching capacity filter, comprise two gain joints, each gain joint produces a zero point and two transmission characteristic functions that limit is all adjustable, can compensate the decay of transmission signals on high frequency to the full extent by regulating zero point, first gain joint provides little high-frequency gain, second gain joint provides big high-frequency gain, high-frequency gain promotes big corresponding transmission line distance, the situation that attenuated input signal is big, and the high-frequency gain lifting is little, then the respective signal transmission range is short, the situation that transmission attenuation is little;
Described gain improvement circuit provides fixedly limit, but the amplification of high frequency zeroising, after whole loop stability, to carry out the compensation on phase place and the frequency through the signal behind the prefilter, make that the decay of balanced ripple on phase place of output is minimum, phase compensation is corresponding with the amplitude compensation, be provided with 8 kinds of phase compensation controls, the decay of corresponding different transmission range signals respectively, putting attainable gain ranging in the Nyquist sample frequency is 0-17db, 8 different step responses are selected by digital control circuit, obtain amplitude and phase place and all carry out balanced signal.
To the E1 signal, gain improvement circuit provides the zero point of a gain near 1.024M, and be to be set by the value of digital control circuit this zero point, is used for the amplitude of input signal is carried out gain compensation and lifting at this frequency place, realizes the compensation of phase place and amplitude.
Described post-filtering circuit is used for the signal that level and smooth gain improvement circuit is exported, and adopts low-pass first order filter to realize.
Described amplitude detection circuit, be used to detect the input signals distance, when initial, automatic gain control circuit placed does not both have the yet zero-decrement state of gain, at this moment the signal that is input to amplitude detection circuit is the transmission and the attenuation of reflected signal truly, is provided with 5 comparative levels corresponding attenuated input signal 8db respectively, 17db, 24db, the value of 32db and 40db;
The unlike signal transmission range, digital control circuit will produce control signal to the carry out attenuation/gain of automatic gain control circuit to input signal, judge through delivering in the amplitude detection circuit again after the automatic gain control circuit adjustment, each step-length of adjusting is 1.7db, feedback constantly carries out detecting appropriate signal up to amplitude detection circuit, promptly Shu Ru signal amplitude after automatic gain control circuit is handled just in time is the value behind the normal signal decay 17db, at this moment the value of digital control signal is fixed, the control signal of automatic gain control circuit is also fixed, the inner ring road stable state is set up, this moment, the digital control circuit input control signal was given gain improvement circuit, to obtain reasonable portfolio effect.
Described clock timing extraction circuit adopts digital phase-locked loop, from the output signal of comparison circuit, extract a 2.048M clock, and the rising edge that makes this clock is just in time in the central authorities of data, the clock that extracts can be at the state of five set level of correct position sampling amplitude detection circuit, and together correctly detect the state of amplitude detection circuit output level with digital control circuit, export correct control signal and give automatic gain control circuit and gain improvement circuit.
Described digital control circuit is made up of two parts, is respectively the AGC numerical control and produces circuit and gain lifting control signal generation circuit, and the clock that the AGC numerical control produces circuit is to be produced by the clock timing extraction circuit, and the AGC numerical control produces circuit and realized by state machine;
Described AGC numerical control produces the initial condition of circuit, the gain of corresponding automatic gain control circuit is 0, this moment automatic gain control circuit the comparative level result that obtains with amplitude detection circuit of output signal, on correct sequential, sampled by digital control circuit, situation according to transmission-line attenuation, the output digital controlled signal is to the automatic gain control circuit adjustment, and after loop stability, gain promotes control signal generation circuit will produce the set of number control signal to gain improvement circuit.
A kind of self adaptation E1 equalizer that the present invention proposes is just in order to satisfy communicating requirement and to overcome above-mentioned equalizer shortcoming and custom-designed, this equilibrium can automatic equalization the non-constant width of scope, can reach several meters to several kilometers, adaptive equalizer can be adjusted the amplitude and the phase characteristic of equalizer adaptively according to the length of transmission line, no matter signal transmission distance is that length or weak point can obtain most suitable and equilibrium accurately like this.
Description of drawings
Fig. 1 is an equalizer position schematic diagram;
Fig. 2 is transmission-line attenuation amplitude and equalizer enlargement range and complete attenuation characteristic and E1 signal frequency relation curve;
Fig. 3 is the transfer curve of transmission line under different transmission ranges;
Fig. 4 is the schematic diagram of adaptive equalizer of the present invention;
Fig. 5 is the automatic gain control circuit structural representation;
Fig. 6 is preposition low-pass filter circuit structural representation;
Fig. 7 is the gain improvement circuit structural representation;
Fig. 8 relates to the frequency response characteristic of Fig. 7;
Fig. 9 is an amplitude detection circuit level schematic diagram;
Figure 10 is the digital control circuit structural representation.
Embodiment
Technical scheme of the present invention: the long line equalizer 100 of a kind of self adaptation, comprise AGC automatic gain control circuit 200, pre-filtering circuit 201, gain improvement circuit (Gain_boost) 202, post-filtering circuit 204, amplitude detection circuit 205 and digital control circuit 203, comparison circuit 207 and clock timing extraction circuit 206.
AGC automatic gain control circuit 200: the effect of this circuit is that the signal of coming in is carried out equilibrium on the amplitude, no matter make outside signal amplitude of coming in is what, just in time is decay value behind the 17db of normal signal through the amplitude of signal behind the agc circuit.Signal through different transmission ranges compensates through all carrying out amplitude behind the agc circuit like this, and the signal that transmission range is long will amplify through amplitude behind the AGC, and the short signal of transmission range will be decayed through behind the AGC.No matter have how long all to make the amplitude of the signal after the AGC output be stable, be the value behind the normal signal decay 17db but the long and is the external signal transmission range.
Pre-filtering circuit 201: this circuit carries out filtering to the E1 signal of outside, thereby removes the decay of self-channel, and pre-filtering circuit 201 adopts traditional RC filter to realize.
Gain improvement circuit (Gain_boost) 202: adopt switched-capacitor circuit to realize, this circuit carries out compensation on the phase place to the waveform of distortion, concerning the E1 signal, signal is decayed maximum on 1.024M, so this circuit provides the zero point of a gain near 1.024M, be to be set by the value of digital control end this zero point, and the effect that be set zero point is that the amplitude of input signal is carried out gain compensation and lifting at this frequency place, thereby reach the purpose of phase place and amplitude compensation.
Post-filtering circuit 204: this circuit is to carrying out filtering through the signal after the equilibrium, the switching noise that filtering gain improvement circuit 202 produces.
Amplitude detection circuit 205: transmit the judgement of line length, be provided with the judgement that five comparative levels are used for realizing transmitting line length here.
Digital control circuit 203: the result who detects according to amplitude detection circuit, promote circuit 202 for automatic gain control circuit 200 and amplitude by the correct control signal of digital control circuit output, be used for adjusting gain and phase place after the automatic gain control circuit equilibrium.
Comparison circuit 207: will change into digital signal through the analog signal of the balanced output of automatic gain control circuit.
Clock timing extraction circuit 206: from the signal of preposition filter circuit 201 outputs, extract clock, the rising edge of this clock is just in time in the central authorities of input signal, this clock is as the clock of digital control part, can correctly detect the state of the level of range detector output, give digital control circuit 203 thereby obtain more correct result.
Further describe the present invention below in conjunction with accompanying drawing.
The design principle of adaptive equalizer 100 of the present invention is such, by transmission line theory as can be known, the decay of transmission line is that the square root of the frequency of transmission signal together is directly proportional and with transmitting distance dependent, the frequency of signal is high more, the transmission range of transmission line is long more, and the decay of signal is big more.In graph of relation shown in Figure 2, abscissa is represented the frequency of E1 signal, and ordinate is represented amplitude, and unit is dB.The attenuation characteristic of transmission line such as curve 2, signal frequency is high more, and transmission-line attenuation is big more, and concerning the E1 signal, signal is when the 1.024MHz frequency, and the decay of transmission line is maximum.The design of equalizer is in order to compensate the decay of transmission line at front end to the full extent, the summit of gain is set at E1 signal frequency 1.024MHz place, and gain reduces beyond the E1 Frequency point, and to prevent the interference of front end, the equalizer frequency characteristic is shown in curve 2.Because the compensation of equalizer makes the characteristic of the network that transmission line and equalizer acting in conjunction are formed be similar to a desirable low-pass characteristic shown in curve 1.If input signal is by such low-pass network, the decay and the distortion meeting of signal are very little.Characteristic curve when Figure 3 shows that transmission line through different distance, as shown in Figure 3, the transmission line distance is long more, and signal attenuation is big more, and equalizer also requires big more in the compensation of front end.
For transmission range is the signal of 0-1500 rice, the distance of transmission line is different, the equalization characteristic of equalizer is also different, and adaptive equalizer will be adjusted the gain and the frequency characteristic of input signal automatically according to the distance of transmission line, with the compensation decay that transmission line was caused.Specifically, the level of input signal is with the detected transmission range of estimating transmission line, and the output corresponding control signal gives equalizer so that optimum gain and frequency compensation to be provided.
Adaptive equalizer 100 of the present invention is by automatic gain control circuit 200, pre-filtering circuit 201, amplitude detection circuit 205, digital control circuit 203, feedback control loop and gain improvement circuit 202 that comparison circuit 207 and clock timing extraction circuit 206 are formed, post-filtering circuit 204 constitutes jointly, as shown in Figure 4.The input signal of this equalizer is RRING and RTIP, and output signal is Vp and Vn.In the process of loop tracks and locking, the feedback control signal that digital control circuit 203 will characterize transmission range offers automatic gain control circuit 200 and carries out the amplitude adjustment, up to loop stability, the sign of loop stability is that the output signal of AGC is the 17db of normal signal decay.After loop stability, digital control circuit 203 is given gain improvement circuit 202 with the input digit control signal, to obtain the compensation of suitable phase place and amplitude, passes through 204 outputs of post-filtering circuit through the signal after phase amplitude compensation and the equilibrium.Said process is mainly finished two purposes, the tracking lock process of loop is judgement and the detection in order to transmit line length, after the loop stability, the transmission line distance has also been determined, at this moment can be according to giving gain improvement circuit 202 with the corresponding set of number control signal of transmission range, to obtain more satisfactory transmission characteristic, obtaining cleaner balanced ripple output by post-filtering circuit 204.
Below in conjunction with Fig. 4 circuit, introduce the course of work of adaptive equalizer in detail, before the loop equilibrium establishment, gain improvement circuit 202 is in initial condition all the time, does not carry out any operation.And gain control circuit 200 also is in the 0db gain-state, because feedback network mainly is used for determining length of transmission line, so loop is in the judgement state of following the tracks of at the beginning, external input signal is finished by amplitude detection circuit 205 through transmission-line attenuation how long, at this moment the digital control signal that requires automatic gain control circuit 200 is 01010, the gain of the automatic gain control circuit 200 that shows is 0, amplitude detection circuit 205 is provided with five comparative levels (A, B, C, D, E) difference respective signal decay 8.5db, 17db, 25.5db, 34db, the level during 42.5db.Because the gain of circuit and decay to 0, truly reflected the attenuation that enters the preceding external signal of transformer so be input to the signal of amplitude detection circuit 205, this signal compares with five comparative levels of amplitude detection circuit, and level ratio result can obtain the digital signal of a more rough sign transmission attenuation situation.Digital control circuit 203 detects the amplitude detection signal on correct sequential, and the signal of amplitude detection judged and export control signal and give automatic gain control circuit 200, change the attenuation/gain value of automatic gain control circuit 200, the principle that automatic gain control circuit 200 is adjusted: the signal that transmission range is long will amplify through automatic gain control circuit 200 back amplitudes, and the short signal of transmission range will be decayed through behind the automatic gain control circuit 200.No matter have how long all to make the amplitude of the signal after automatic gain control circuit 200 output be stable, be the 17db of normal signal attenuation amplitude promptly through the signal behind the automatic gain control circuit 200 but the long and is the external signal transmission range.As signal transmission distance is 0 meter, and then the numerical control end of automatic gain control circuit 200 will make it place 17db decay, if signal transmission distance is 1500 meters, then the gain that will make of the numerical control end of automatic gain control circuit 200 places the 25db gain.The adjustment of automatic gain control circuit 200 is a step-length adjustment by 1.7db, every adjustment once, amplitude detection circuit 205 all will detect the output signal of automatic gain control circuit 200 again, obtain new level comparative result, then readjust the output of automatic gain control circuit 200, so whole loop is constantly to follow the tracks of to adjust, meet the demands up to the output of automatic gain control circuit 200.After the loop stability, automatic gain control circuit 200 digital control signals will truly reflect the attenuation of external transmission lines, automatic gain control circuit 200 maximum attenuation digital control values are with the shortest situation of corresponding transmission range, and automatic gain control circuit 200 maximum gain digital control values will be the longest to transmission range situation, so just can determine the transmission range of transmission line by the digital control value of automatic gain control circuit 200.After the transmission line distance was determined, digital control circuit 203 just can be exported one group of control signal according to transmission range and give gain improvement circuit 202, by changing the amplitude and the phase characteristic of gain improvement circuit 202, reaches the automatic equalization and the compensation of amplitude and phase place.
Can adjust the frequency individual features of whole equalizer adaptively according to the distance of transmission line by above-mentioned FEEDBACK CONTROL, to reach reasonable portfolio effect.
Be described in further detail each built-up circuit below in conjunction with accompanying drawing:
Automatic gain control circuit 200 circuit: the effect of automatic gain control circuit 200 circuit is that the signal of coming in is carried out equilibrium on the amplitude, no matter make how many sizes of outside signal amplitude of coming in is, the amplitude of signal just in time is the value behind the normal signal decay 17db behind process automatic gain control circuit 200 circuit.The short signal of transmission range will be decayed through automatic gain control circuit 200 amplitudes and the long signal of transmission range will amplify through automatic gain control circuit 200 back amplitudes like this.The size that automatic gain control circuit 200 gains are adjusted is controlled by digital control circuit 203, gain and decay factor by five groups of programmable digital control automatic gain control circuit 200 circuit, circuit decay gain adjustment scope is-and 17db is to+25db, and the step-length that automatic gain control circuit 200 is adjusted is 1.7db.
The structure chart of automatic gain control circuit 200 circuit as shown in Figure 5, this circuit is made up of two programmable amplifiers, digital control signal D_AGC[0:3] control the gain of first programmable amplifier 300, and the gain of second programmable amplifier 301 of digital control signal D_AGC4 control.When the control signal D_AGC4 of AGC was 0, the gain of second programmable amplifier 301 was 0db, and when D_AGC4 was 1, the gain of second programmable amplifier 301 was 17db.Digital control circuit 203 provides gain and the decay of set of number signal to control it for automatic gain control circuit 200 circuit.The variation each time of digital control value will cause that all automatic gain control circuit 200 goes to amplify or decays and be input to signal in the equalizer with the gain or the factor of decay that each step-length 1.7db adjusts it.After the amplitude of whole loop reached the value of normal signal decay 17db, gain and decay factor were maintained fixed.
Automatic gain control circuit 200 circuit numerical control values, the relation table of corresponding gain reduction db number and transmission line length is as follows:
| The transmission range of transmission line | D_AGC4，D_AGC3，D_AGC2， D_AGC1，D_AGC0 | The decay of corresponding agc circuit |
| ?0-60m | ?00000 | -17db |
| ?60m-120m | ?00001 | -15.3db |
| ?120m-180m | ?00010 | -13.6db |
| ?180m-240m | ?00011 | -11.9db |
| ?240m-300m | ?00100 | -10.2db |
| ?300m-360m | ?00101 | -8.5db |
| ?360m-420m | ?00110 | -6.8db |
| ?420m-480m | ?00111 | -5.1db |
| ?480m-540m | ?01000 | -3.4db |
| ?540m-600m | ?01001 | -1.7db |
| ?600m-660m | ?01010 | 0db |
| ?660m-720m | ?01011 | 1.7db |
| ?720m-780m | ?01100 | 3.4db |
| ?780m-840m | ?01101 | 5.1db |
| ?840m-900m | ?01110 | 6.8db |
| ?900m-960m | ?01111 | 8.5db |
Table 1
When D_AGC4=1, D_AGC[3:0] corresponding value be
| ?960m-1020m | ?10110 | ?10.2db |
| ?1020m-1080m | ?10111 | ?11.9db |
| ?1080m-1140m | ?11000 | ?13.6db |
| ?1140m-1200m | ?11001 | ?15.3db |
| ?1200m-1260m | ?11010 | ?17db |
| ?1260m-1320m | ?11011 | ?18.7db |
| ?1320m-1380m | ?11100 | ?20.4db |
| ?1380m-1440m | ?11101 | ?22.1db |
| ?1440-1500m | ?11110 | ?23.8db |
| ?1500m- | ?11111 | ?25.5db |
Table 2
Pre-filtering circuit 201: pass through a second-order low-pass filter through the signal behind the automatic gain control circuit 200, filter circuit configuration as shown in Figure 6, this circuit is a kind of unlimited gain multichannel feedback low pass filter, is made up of jointly with the high-gain amplifier resistance-capacitance network.Be characterized in that output from amplifier is to a plurality of negative feedbacks are arranged the end of oppisite phase, be that output signal feeds back to input through R2p (R2n) and R3p (R3n), or directly feed back to input by capacitor C 1 and C2, this filter requires the long-pending upper limit much larger than filter bandwidht of bandwidth of operational amplifiers gain, because adopt the output of both-end input both-end, inner amplifier need adopt the common-mode feedback technology.Physical circuit is analyzed as follows, under high frequency, and C1, C3, C4, C5 is equivalent to short circuit, and transfer function is 0, and under low frequency, C1, C3, C4, C5 are equivalent to open circuit.This filter circuit is decayed by a precipitous frequency is provided, the noise and the interference that come the filtering external input signal, and the signal that limits other frequency enters the Gain_boost circuit, and only will carry the E1 signal of the frequency of usefulness.
Gain improvement circuit 202: gain improvement circuit 202 is made up of switching capacity filter, and fixedly limit is provided, but the amplification of high frequency zeroising.After whole loop stability,, make that the decay of balanced ripple on phase place of output is minimum to carry out the compensation on phase place and the frequency through the signal behind the pre-filtering circuit.Phase compensation is corresponding with the amplitude compensation.It has 8 kinds of phase compensation controls, the decay of corresponding different transmission range signals respectively, and putting attainable gain ranging in the Nyquist sample frequency is 0-17db.8 different step responses are selected by digital control circuit.The signal that obtains like this is that amplitude and phase place are all carried out balanced signal.
Following table is the line length of transmission line, relation such as table 3 that the control signal of Gain_boost circuit 202 and Gain_boost low-frequency gain and rf amplitude promote.
| The line length of transmission | The Gain_boost circuit control signal | The low-frequency gain A of Gain_boost | The value B of the lifting of the high frequency of Gain_boost (boost) |
| ?0m-180m | ?000 | ?17db | ?0.5db |
| ?240m-360m | ?001 | ?20db | ?2.5db |
| ?420m-540m | ?010 | ?23db | ?4.5db |
| ?600m-720m | ?011 | ?26db | ?7db |
| ?780m-900m | ?100 | ?29db | ?9.5db |
| ?960m-1140m | ?101 | ?32db | ?12db |
| ?1140m-1260m | ?110 | ?35db | ?14.5db |
| ?1320m-1500m | ?111 | ?38db | ?17db |
Table 3
Above-mentioned relation can be referring to Fig. 8, and Fig. 8 is the frequency response characteristic of gain improvement circuit 202, and A represents the low-frequency gain of gain improvement circuit 202 among the figure, and B represents the lifting values of gain improvement circuit 202 under high frequency.Can see that thus signal transmission distance is long more, signal attenuation is big more, and then the lifting values of high frequency compensation is big more.
Post-filtering circuit 204: be used for level and smooth signal after the agc circuit equilibrium, because gain improvement circuit adopts switched-capacitor circuit to realize, so there is switching noise inevitably, switching noise is the signal of a high frequency, so need post-filtering circuit 204 to come this high-frequency noise of filtering.This circuit adopts low-pass first order filter, and ratio simple in structure is easier to realize.
Amplitude detection circuit 205: amplitude detection circuit 205 is used for detecting the input signals distance, and during initial situation, automatic gain control circuit 200 placed does not both have the yet zero-decrement state of gain, at this moment the signal that is input to amplitude detection circuit 205 is the transmission and the attenuation of reflected signal truly, is provided with 5 comparative level A here, B, C, D, E, as shown in Figure 9, A, B, C, D, E is corresponding attenuated input signal 8db respectively, 17db, 24db, the value of 32db and 40db.Level B is the reference level of respective signal decay, if the amplitude of input signal is greater than A, or the amplitude that input signal then is described between AB is too high, signal transmission distance is shorter, at this moment digital control signal will produce that control signal is given automatic gain control circuit 200 so that the decaying of input signal, process automatic gain control circuit 200 adjusted circuit are delivered in the amplitude detection circuit 205 again and are judged, if signal amplitude is still bigger, then automatic gain control circuit 200 continue decay up to the amplitude of input signal less than B, each step-length of adjusting is 1.7db, if the amplitude of input signal is less than B, the attenuation ratio that input signal then is described is bigger, the transmission range of signal is long, at this moment the adjustment numerical value of automatic gain control circuit 200 will be looked input signal and fall into C, D, the scope of E and deciding, each step-length of adjusting is 1.7db, up to the amplitude of input signal greater than B.This feedback constantly carries out detecting appropriate signal (signal of promptly coming in amplitude after automatic gain control circuit 200 is handled just in time is the value behind the normal signal decay 17db) up to amplitude detection circuit 205.At this moment the value of digital control signal is fixed, and the control signal of automatic gain control circuit 200 is also fixed, and the inner ring road stable state is set up, and this moment, the digital control signal input control signal was given gain improvement circuit 202, to obtain reasonable portfolio effect.
Digital control circuit is made up of two parts as shown in figure 10, is respectively the AGC numerical control and produces circuit 500 and gain lifting control signal generation circuit 501, and the clock that the AGC numerical control produces circuit 500 is produced by clock timing extraction circuit 206.The AGC numerical control produces circuit 500 and can be realized by state machine, and the initial value that the AGC numerical control produces the numerical control part of circuit 500 is 01010 state, and under this state, automatic gain control circuit 200 circuit gains are 0.At this moment the amplitude of automatic gain control circuit 200 output signals has truly reflected the attenuation of external input signal, and this output signal obtains comparative level ABCDE with the result of amplitude detection circuit after relatively.The ABCDE level is sampled by digital-control circuit on correct sequential, and according to the situation of transmission-line attenuation, the output of ABCDE has 6 kinds of situations, and is as shown in the table:
| The attenuated input signal situation | The ABCDE output valve | Corresponding transmission range | The adjusting range of AGC control signal |
| ?0-8db | ????11111 | ?0m-300m | ?00000-00101 |
| ?8db-17db | ????01111 | ?300m-600m | ?00101-01010 |
| ?17db-24db | ????00111 | ?600m-840m | ?01010-01110 |
| ?24db-32db | ????00011 | ?840m-1140m | ?01110-11001 |
| ?32db-40db | ????00001 | ?1140m-1400m | ?11001-11110 |
| Greater than 40db | ????00000 | ?1400m-1500m | ?11110-11111 |
Table 4
Because it is the value of normal signal decay 17db that the output of automatic gain control circuit 200 requires, so if the initial attenuated output signal of automatic gain control circuit 200 is little, show that then the external signal transmission range is short, at this moment adjust the numerical control output of automatic gain control circuit 200, the decay of automatic gain control circuit 200 is increased gradually, numerical control value of every adjustment will cause the decay factor adjustment 1.7db of automatic gain control circuit 200, the output valve of new automatic gain control circuit 200 will continue to compare with amplitude detection circuit, if the output of ABCDE is near the B level, then the output of automatic gain control circuit 200 is fixed, loop stability is no longer adjusted, otherwise the numerical control of automatic gain control circuit 200 continues to adjust, the decay of the output resume of automatic gain control circuit 200 meets the demands up to the output valve of ABCDE.If the initial attenuated output signal of automatic gain control circuit 200 is big, show that then the external signal transmission range is long, at this moment adjust the numerical control output of automatic gain control circuit 200, the gain of automatic gain control circuit 200 is increased gradually, numerical control value of every adjustment will cause the gain factor adjustment 1.7db of automatic gain control circuit 200, the output valve of new automatic gain control circuit 200 will continue to compare with amplitude detection circuit, if the output of ABCDE is near the B level, then the output of automatic gain control circuit 200 is fixed, loop stability is no longer adjusted, otherwise the numerical control of automatic gain control circuit 200 continues to adjust, the output resume of automatic gain control circuit 200 increases, and meets the demands up to the output valve of ABCDE.
After the loop stability, gain promotes control signal generation circuit 501 will produce one group of control signal to gain improvement circuit 200, automatic gain control circuit 200 is finished is that signal to the outside input has carried out the adjustment on the amplitude, and the equilibrium on the phase place then is to depend on the compensation that gain improvement circuit 202 realizes high frequency.The digital value of automatic gain control circuit 200 is with corresponding relation such as the following table of Gain_boost:
| The control signal of AGC | The Gain_boost circuit control signal |
| ?00000-00011 | ?000 |
| ?00100-00110 | ?001 |
| ?00111-01001 | ?010 |
| ?01010-01100 | ?011 |
| ?01101-01111 | ?100 |
| ?10000-10010 | ?101 |
| ?10011-10101 | ?110 |
| ?10110-11001 | ?111 |
Table 5
The numerical control part can be indicated the distance of transmission line, and changing index signal can or deposit in the register by pin output.
In sum, adopt adaptive equalizer of the present invention, can adjust the frequency response characteristic of whole equalizing network automatically adaptively according to the transmission range of external transmission lines, thereby in very wide transmission range (0-1500 rice), can realize good portfolio effect.
Claims (9)
1. one kind is used for the adaptive equalization device that SDH transmission system Line Attenuation compensates, it is characterized in that: this device is by automatic gain control circuit, the pre-filtering circuit, amplitude detection circuit, digital control circuit, feedback control loop and gain improvement circuit that comparison circuit and clock timing extraction circuit are formed, the post-filtering circuit is formed;
Automatic gain control circuit is used for the signal of input is carried out equilibrium on the amplitude, no matter make the signal amplitude of outside input is what, just in time is decay value behind the 17db of normal signal through the amplitude of signal behind the automatic gain control circuit;
The pre-filtering circuit is used for removing the decay of self-channel to carrying out filtering through the outside E1 signal after the automatic gain control circuit equilibrium, adopts traditional RC filter to realize;
Gain improvement circuit is used for waveform to distortion and carries out compensation on the phase place, adopts switched-capacitor circuit to realize;
The post-filtering circuit is used for the signal after promoting through balanced, gain is carried out filtering, the switching noise that the filtering gain improvement circuit produces;
Amplitude detection circuit by five comparative levels are set, is used to transmit the judgement of line length;
Digital control circuit according to the result that amplitude detection circuit detects, is exported correct control signal and is given automatic gain control circuit and gain improvement circuit, is used to adjust gain and phase place after the automatic gain control circuit equilibrium;
Comparison circuit, the analog signal that is used for being exported through the automatic gain control circuit equilibrium changes into digital signal;
The clock timing extraction circuit, be used for extracting clock from the signal that preposition filter circuit is exported, the rising edge of this clock is just in time in the central authorities of data, this clock is as the clock of digital control circuit, correctly detect the state of amplitude detection circuit output level, give digital control circuit thereby obtain more correct result;
Described gain improvement circuit begins to be initial condition, automatic gain control circuit begins the gain-state for 0db, data are decayed by five set comparative levels difference respective signal of amplitude detection circuit through different transmission-line attenuations, obtain the digital signal of a more rough sign transmission attenuation situation, on correct sequential, detect the amplitude detection signal by digital control circuit, and the signal of amplitude detection judged and export control signal and give automatic gain control circuit, change the attenuation/gain value of automatic gain control circuit, the result of automatic gain control circuit adjustment is the amplitude stabilization that makes output back signal, be the 17db of normal signal attenuation amplitude promptly through the signal behind the automatic gain control circuit, after the loop stability, the automatic gain control circuit digital control signal will truly reflect the attenuation of external transmission lines, after the transmission line distance is determined, digital control circuit just can be exported one group of control signal according to transmission range and give gain improvement circuit, by changing the amplitude and the phase characteristic of gain improvement circuit, reach the automatic equalization and the compensation of amplitude and phase place.
2. be used for the adaptive equalization device of SDH transmission system Line Attenuation compensation according to claim 1, it is characterized in that:
Described automatic gain control circuit is made up of two programmable amplifiers, provides the set of number control signal by digital control circuit to automatic gain control circuit, with ride gain and decay;
The variation each time of described digital controlled signal, automatic gain control circuit removes the signal that amplifies or decay and import with the factor that each step-length 1.7db adjusts gain or decay;
After the amplitude of whole loop reached the value of normal signal decay 17db, gain and decay factor were maintained fixed.
3. be used for the adaptive equalization device of SDH transmission system Line Attenuation compensation according to claim 1, it is characterized in that:
Described pre-filtering circuit, it is a second-order low-pass filter, form unlimited gain multichannel feedback low pass filter by resistance-capacitance network and high-gain amplifier, from the output of amplifier to being provided with a plurality of negative feedbacks the end of oppisite phase, be that output signal is passed through resistance or directly arrived input by capacitive feedback, the long-pending upper limit much larger than filter bandwidht of bandwidth of operational amplifiers gain in the described filter adopts the output of both-end input both-end, and inner amplifier adopts common-mode feedback;
Under high frequency, electric capacity is equivalent to short circuit, and transfer function is 0, and under low frequency, electric capacity is equivalent to open circuit;
Described pre-filtering circuit provides a precipitous frequency decay, the noise of filtering external input signal and interference, and the signal that limits other frequency enters gain improvement circuit, obtains the E1 signal of useful frequency.
4. be used for the adaptive equalization device of SDH transmission system Line Attenuation compensation according to claim 1, it is characterized in that:
Described gain improvement circuit is made up of switching capacity filter, comprise two gain joints, each gain joint produces a zero point and two transmission characteristic functions that limit is all adjustable, can compensate the decay of transmission signals on high frequency to the full extent by regulating zero point, first gain joint provides little high-frequency gain, second gain joint provides big high-frequency gain, high-frequency gain promotes big corresponding transmission line distance, the situation that attenuated input signal is big, and the high-frequency gain lifting is little, then the respective signal transmission range is short, the situation that transmission attenuation is little;
Described gain improvement circuit provides fixedly limit, but the amplification of high frequency zeroising, after whole loop stability, to carry out the compensation on phase place and the frequency through the signal behind the prefilter, make that the decay of balanced ripple on phase place of output is minimum, phase compensation is corresponding with the amplitude compensation, be provided with 8 kinds of phase compensation controls, the decay of corresponding different transmission range signals respectively, putting attainable gain ranging in the Nyquist sample frequency is 0-17db, 8 different step responses are selected by digital control circuit, obtain amplitude and phase place and all carry out balanced signal.
5. as described in claim 4, be used for the adaptive equalization device that SDH transmission system Line Attenuation compensates, it is characterized in that:
To the E1 signal, gain improvement circuit provides the zero point of a gain near 1.024M, and be to be set by the value of digital control circuit this zero point, is used for the amplitude of input signal is carried out gain compensation and lifting at this frequency place, realizes the compensation of phase place and amplitude.
6. be used for the adaptive equalization device of SDH transmission system Line Attenuation compensation according to claim 1, it is characterized in that:
Described post-filtering circuit is used for the signal that level and smooth gain improvement circuit is exported, and adopts low-pass first order filter to realize.
7. be used for the adaptive equalization device of SDH transmission system Line Attenuation compensation according to claim 1, it is characterized in that:
Described amplitude detection circuit, be used to detect the input signals distance, when initial, automatic gain control circuit placed does not both have the yet zero-decrement state of gain, at this moment the signal that is input to amplitude detection circuit is the transmission and the attenuation of reflected signal truly, is provided with 5 comparative levels corresponding attenuated input signal 8db respectively, 17db, 24db, the value of 32db and 40db;
The unlike signal transmission range, digital control circuit will produce control signal to the carry out attenuation/gain of automatic gain control circuit to input signal, judge through delivering in the amplitude detection circuit again after the automatic gain control circuit adjustment, each step-length of adjusting is 1.7db, feedback constantly carries out detecting appropriate signal up to amplitude detection circuit, promptly Shu Ru signal amplitude after automatic gain control circuit is handled just in time is the value behind the normal signal decay 17db, at this moment the value of digital control signal is fixed, the control signal of automatic gain control circuit is also fixed, the inner ring road stable state is set up, this moment, the digital control circuit input control signal was given gain improvement circuit, to obtain reasonable portfolio effect.
8. be used for the adaptive equalization device of SDH transmission system Line Attenuation compensation according to claim 1, it is characterized in that:
Described clock timing extraction circuit adopts digital phase-locked loop, from the output signal of comparison circuit, extract a 2.048M clock, and the rising edge that makes this clock is just in time in the central authorities of data, the clock that extracts can be at the state of five set level of correct position sampling amplitude detection circuit, and together correctly detect the state of amplitude detection circuit output level with digital control circuit, export correct control signal and give automatic gain control circuit and gain improvement circuit.
9. be used for the adaptive equalization device of SDH transmission system Line Attenuation compensation according to claim 1, it is characterized in that:
Described digital control circuit is made up of two parts, is respectively the AGC numerical control and produces circuit and gain lifting control signal generation circuit, and the clock that the AGC numerical control produces circuit is to be produced by the clock timing extraction circuit, and the AGC numerical control produces circuit and realized by state machine;
Described AGC numerical control produces the initial condition of circuit, the gain of corresponding automatic gain control circuit is 0, this moment automatic gain control circuit the comparative level result that obtains with amplitude detection circuit of output signal, on correct sequential, sampled by digital control circuit, situation according to transmission-line attenuation, the output digital controlled signal is to the automatic gain control circuit adjustment, and after loop stability, gain promotes control signal generation circuit will produce the set of number control signal to gain improvement circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB03131824XA CN1306719C (en) | 2003-06-05 | 2003-06-05 | Self-adaptation balancing apparatus for SDH transmission system circuit attenuation compensation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB03131824XA CN1306719C (en) | 2003-06-05 | 2003-06-05 | Self-adaptation balancing apparatus for SDH transmission system circuit attenuation compensation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1553588A true CN1553588A (en) | 2004-12-08 |
| CN1306719C CN1306719C (en) | 2007-03-21 |
Family
ID=34322963
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB03131824XA Expired - Fee Related CN1306719C (en) | 2003-06-05 | 2003-06-05 | Self-adaptation balancing apparatus for SDH transmission system circuit attenuation compensation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1306719C (en) |
Cited By (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101167326B (en) * | 2005-04-27 | 2010-09-29 | 松下电器产业株式会社 | Polar modulation transmission circuit and communication device |
| CN101500123B (en) * | 2008-01-31 | 2011-08-03 | 宏正自动科技股份有限公司 | Image distributor having video compensation function and compensating method thereof |
| CN102282774A (en) * | 2008-11-18 | 2011-12-14 | 格努姆有限公司 | Folding sequential adaptive equalizer |
| EP2436174A1 (en) * | 2009-05-29 | 2012-04-04 | Sagemcom Broadband Sas | Method for correcting telephone signal degradation caused by the length of the analog line via the receiver |
| CN102710891A (en) * | 2012-05-16 | 2012-10-03 | 浙江大华技术股份有限公司 | Nonlinear gain control method and device as well as equipment |
| CN102801444A (en) * | 2012-07-06 | 2012-11-28 | 华为技术有限公司 | Analogue balancing device and method |
| CN103152584A (en) * | 2012-07-20 | 2013-06-12 | 浙江大华技术股份有限公司 | Method and system of analog video signal gain control |
| CN103685104A (en) * | 2013-12-03 | 2014-03-26 | 苏州仙林力齐电子科技有限公司 | Two-step adaptive equalizer and logic control method thereof |
| CN105024669A (en) * | 2015-08-14 | 2015-11-04 | 成都易思科科技有限公司 | Active low-pass filter circuit using 4580 operation amplifier |
| CN105472293A (en) * | 2014-08-22 | 2016-04-06 | 浙江大华技术股份有限公司 | Method and device for realizing video signal equalization |
| CN105588609A (en) * | 2016-02-24 | 2016-05-18 | 叶志刚 | Device used for detecting mosquitoes |
| CN106105122A (en) * | 2014-03-20 | 2016-11-09 | 三菱电机株式会社 | Process circuit and signal calibration method |
| CN106656876A (en) * | 2015-10-28 | 2017-05-10 | 北京华大九天软件有限公司 | Continuous time linear adaptive equalizer circuit applied to SERDES receiver |
| CN107517331A (en) * | 2016-06-17 | 2017-12-26 | 浙江大华技术股份有限公司 | A kind of automatic amplitude adjusting method and balanced device for cable transmission |
| CN110166062A (en) * | 2018-02-14 | 2019-08-23 | 円星科技股份有限公司 | Transmitter and related post-equalization system |
| CN110247634A (en) * | 2019-06-24 | 2019-09-17 | 成都芯通软件有限公司 | A kind of broadband high precision apparatus output level band slope temperature compensation method and system |
| CN111697994A (en) * | 2020-06-24 | 2020-09-22 | 天津中科海高微波技术有限公司 | Novel adjustable amplitude equalizer |
| CN112468244A (en) * | 2020-10-30 | 2021-03-09 | 南京微毫科技有限公司 | Balanced delay module and transceiving frequency conversion channel system with same |
| CN112702291A (en) * | 2020-12-24 | 2021-04-23 | 成都振芯科技股份有限公司 | Adaptive equalizer and adjusting range expanding method thereof |
| CN112804169A (en) * | 2021-01-20 | 2021-05-14 | 浪潮电子信息产业股份有限公司 | High-speed signal equalization parameter optimization method, system and related components |
| CN113872568A (en) * | 2021-12-02 | 2021-12-31 | 南京沁恒微电子股份有限公司 | Self-adaptive digital pre-equalization method and system suitable for hundred-mega Ethernet |
| CN117375538A (en) * | 2023-10-09 | 2024-01-09 | 新港海岸(北京)科技有限公司 | Attenuation compensation method and attenuation compensation circuit |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9700440D0 (en) * | 1997-01-10 | 1997-02-26 | Plessey Telecomm | Operation of optical modulators |
| KR100340178B1 (en) * | 2000-08-22 | 2002-06-15 | 선우명훈 | equalizer with Decision Feedback Equalizer structure |
| CN1409511A (en) * | 2001-09-30 | 2003-04-09 | 深圳市中兴通讯股份有限公司上海第二研究所 | Self adaptive stube equalizer |
-
2003
- 2003-06-05 CN CNB03131824XA patent/CN1306719C/en not_active Expired - Fee Related
Cited By (36)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101167326B (en) * | 2005-04-27 | 2010-09-29 | 松下电器产业株式会社 | Polar modulation transmission circuit and communication device |
| CN101500123B (en) * | 2008-01-31 | 2011-08-03 | 宏正自动科技股份有限公司 | Image distributor having video compensation function and compensating method thereof |
| CN102282774A (en) * | 2008-11-18 | 2011-12-14 | 格努姆有限公司 | Folding sequential adaptive equalizer |
| CN102282774B (en) * | 2008-11-18 | 2014-08-13 | 西姆特科加拿大有限公司 | Folding sequential adaptive equalizer |
| EP2436174A1 (en) * | 2009-05-29 | 2012-04-04 | Sagemcom Broadband Sas | Method for correcting telephone signal degradation caused by the length of the analog line via the receiver |
| CN102439958A (en) * | 2009-05-29 | 2012-05-02 | 萨热姆通信宽带简易股份有限公司 | Method for correcting telephone signal degradation caused by the length of the analog line via the receiver |
| CN102439958B (en) * | 2009-05-29 | 2014-12-10 | 萨热姆通信宽带简易股份有限公司 | Method for correcting telephone signal degradation caused by the length of the analog line via the receiver |
| CN102710891B (en) * | 2012-05-16 | 2014-04-09 | 浙江大华技术股份有限公司 | Nonlinear gain control method and device as well as equipment |
| CN102710891A (en) * | 2012-05-16 | 2012-10-03 | 浙江大华技术股份有限公司 | Nonlinear gain control method and device as well as equipment |
| CN102801444B (en) * | 2012-07-06 | 2015-01-21 | 华为技术有限公司 | Analogue balancing device and method |
| CN102801444A (en) * | 2012-07-06 | 2012-11-28 | 华为技术有限公司 | Analogue balancing device and method |
| CN103152584A (en) * | 2012-07-20 | 2013-06-12 | 浙江大华技术股份有限公司 | Method and system of analog video signal gain control |
| CN103152584B (en) * | 2012-07-20 | 2015-02-18 | 浙江大华技术股份有限公司 | Method and system of analog video signal gain control |
| CN103685104A (en) * | 2013-12-03 | 2014-03-26 | 苏州仙林力齐电子科技有限公司 | Two-step adaptive equalizer and logic control method thereof |
| CN106105122B (en) * | 2014-03-20 | 2019-07-16 | 三菱电机株式会社 | Processing circuit and signal calibration method |
| CN106105122A (en) * | 2014-03-20 | 2016-11-09 | 三菱电机株式会社 | Process circuit and signal calibration method |
| CN105472293A (en) * | 2014-08-22 | 2016-04-06 | 浙江大华技术股份有限公司 | Method and device for realizing video signal equalization |
| CN105024669A (en) * | 2015-08-14 | 2015-11-04 | 成都易思科科技有限公司 | Active low-pass filter circuit using 4580 operation amplifier |
| CN106656876A (en) * | 2015-10-28 | 2017-05-10 | 北京华大九天软件有限公司 | Continuous time linear adaptive equalizer circuit applied to SERDES receiver |
| CN106656876B (en) * | 2015-10-28 | 2019-07-09 | 北京华大九天软件有限公司 | A kind of continuous time linear adaptive equalizer circuit applied to the receiving end SERDES |
| CN105588609A (en) * | 2016-02-24 | 2016-05-18 | 叶志刚 | Device used for detecting mosquitoes |
| CN107517331B (en) * | 2016-06-17 | 2019-12-24 | 浙江大华技术股份有限公司 | Automatic amplitude adjusting method and equalizer for cable transmission |
| CN107517331A (en) * | 2016-06-17 | 2017-12-26 | 浙江大华技术股份有限公司 | A kind of automatic amplitude adjusting method and balanced device for cable transmission |
| CN110166062A (en) * | 2018-02-14 | 2019-08-23 | 円星科技股份有限公司 | Transmitter and related post-equalization system |
| CN110247634A (en) * | 2019-06-24 | 2019-09-17 | 成都芯通软件有限公司 | A kind of broadband high precision apparatus output level band slope temperature compensation method and system |
| CN110247634B (en) * | 2019-06-24 | 2023-03-21 | 成都芯通软件有限公司 | Broadband high-precision equipment output level band slope temperature compensation method and system |
| CN111697994B (en) * | 2020-06-24 | 2021-07-09 | 天津中科海高微波技术有限公司 | Novel adjustable amplitude equalizer |
| CN111697994A (en) * | 2020-06-24 | 2020-09-22 | 天津中科海高微波技术有限公司 | Novel adjustable amplitude equalizer |
| CN112468244B (en) * | 2020-10-30 | 2022-06-24 | 南京微毫科技有限公司 | Balanced delay method and transceiving frequency conversion channel system with balanced delay module |
| CN112468244A (en) * | 2020-10-30 | 2021-03-09 | 南京微毫科技有限公司 | Balanced delay module and transceiving frequency conversion channel system with same |
| CN112702291A (en) * | 2020-12-24 | 2021-04-23 | 成都振芯科技股份有限公司 | Adaptive equalizer and adjusting range expanding method thereof |
| CN112702291B (en) * | 2020-12-24 | 2022-08-19 | 成都振芯科技股份有限公司 | Adaptive equalizer and adjusting range expanding method thereof |
| CN112804169A (en) * | 2021-01-20 | 2021-05-14 | 浪潮电子信息产业股份有限公司 | High-speed signal equalization parameter optimization method, system and related components |
| CN112804169B (en) * | 2021-01-20 | 2022-11-04 | 浪潮电子信息产业股份有限公司 | High-speed signal equalization parameter optimization method, system and related components |
| CN113872568A (en) * | 2021-12-02 | 2021-12-31 | 南京沁恒微电子股份有限公司 | Self-adaptive digital pre-equalization method and system suitable for hundred-mega Ethernet |
| CN117375538A (en) * | 2023-10-09 | 2024-01-09 | 新港海岸(北京)科技有限公司 | Attenuation compensation method and attenuation compensation circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1306719C (en) | 2007-03-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1306719C (en) | Self-adaptation balancing apparatus for SDH transmission system circuit attenuation compensation | |
| CN101420209B (en) | High speed large dynamic range digital automatic gain control circuit | |
| EP1727279B1 (en) | Automatic gain control using multi-comparators | |
| CN103220018B (en) | Control method of automatic gain in power line carrier communication network | |
| CN1134112C (en) | Mobile station having emitting power control system | |
| CN1655483A (en) | Continuous time filter-decision feedback equalizer for optical channel equalization | |
| CA2201834A1 (en) | Serial digital data communications receiver with improved automatic cable equalizer, agc system, and dc restorer | |
| CN101635694A (en) | Adaptive equalizer and method for adaptive equalization | |
| CN1363138A (en) | Automatic gain control method and automatic gain control processor and demodulator | |
| Ying et al. | A 20Gb/s digitally adaptive equalizer/DFE with blind sampling | |
| EP2239844A3 (en) | Automatic gain control method and apparatus | |
| CN104954033B (en) | A kind of speed automatic gain for ofdm system controls circuit and method | |
| CN1622468A (en) | A signal processing method and apparatus | |
| CN2762440Y (en) | Signal processing device | |
| CN105357749B (en) | A kind of new type auto gain control method for digital communication | |
| CN101039152A (en) | Method and system for realizing electrical dispersion compensation | |
| CN1409511A (en) | Self adaptive stube equalizer | |
| CN1744473A (en) | Carrier optical receiver front feed automatic gain control method and optical receiver using same | |
| CN1710807A (en) | Amplifying apparatus with automatic gain controlling circuit | |
| US20060045217A1 (en) | Dynamic range signal to noise optimization system and method for receiver | |
| CN114006588A (en) | Infrared touch screen signal amplification system and method | |
| CN201571025U (en) | Optical AGC control circuit used for optical receiver | |
| CN111245765A (en) | Wired carrier communication signal adaptive gain tracking and capturing method and device | |
| CN1092861C (en) | Limited impulse excited response electric filter equalizer with low noise and its noise reducing method | |
| CN101917213B (en) | Adaptive equalization system and adaptive equalization method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20151030 Address after: Dameisha Yantian District of Shenzhen City, Guangdong province 518085 Building No. 1 Patentee after: SANECHIPS TECHNOLOGY Co.,Ltd. Address before: Department of law law ZTE building 518057 Shenzhen City, Nanshan District hi tech Industrial Development Zone Patentee before: ZTE Corp. |
|
| EE01 | Entry into force of recordation of patent licensing contract |
Application publication date: 20041208 Assignee: Xi'an Chris Semiconductor Technology Co.,Ltd. Assignor: SANECHIPS TECHNOLOGY Co.,Ltd. Contract record no.: 2019440020036 Denomination of invention: Self-adaptation balancing apparatus for SDH transmission system circuit attenuation compensation Granted publication date: 20070321 License type: Common License Record date: 20190619 |
|
| EE01 | Entry into force of recordation of patent licensing contract | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20070321 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |