KR101849529B1 - Coupling transformer of wide band power line communication modem combined channel equalizer - Google Patents

Abstract

The present invention relates to a coupling transformer of a broadband power line modem having a channel equalizer combined with a broadband power line modem for improving communication performance by minimizing a band loss and distortion generated when a signal passes through a bandpass filter through a channel equalizer .
The coupling transformer 40 of the broadband power line modem according to the present invention receives the PLC signal from the transmitting end of the power line modem performing the power line communication (PLC), couples the PLC signal to the power line, , And a reverse connection of a PLC signal received from a power line to a receiving end of a power line modem. In the coupling transformer of the power line modem, the PLC signal transmitter and receiver of the coupling transformer (40) And a channel equalizer 90 constituted by an LRC resonance circuit to which the inductor L and the inductor L are connected are coupled to each other to compensate for signal distortion occurring when the power line signal is transmitted and received in the power line modem, / RTI >

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a coupling transformer for a broadband power line modem having a channel equalizer,

The present invention relates to a coupling transformer of a broadband power line modem, and more particularly, to a method of minimizing a bandwidth loss and a distortion occurring when a signal passes through a bandpass filter in a broadband power line modem through a channel equalizer, To a coupling transformer of a broadband power line modem coupled with a channel equalizer.

Power line communication (PLC) is a technology for transmitting voice and data on a high frequency signal through a power line supplying power, and it is capable of data transmission of 200 Mbits per second. Typically, each home, company, factory, etc. has a power outlet to receive power. Powerline communication is the broadest network because it can communicate with a power line modem by connecting it to the power outlet. In addition, since a communication line is not separately installed for communication, a conventional power line is used.

Power line modems that enable such power line communication require various amplification circuits, switching circuits and filters for transmitting and receiving signals. In particular, power lines are not designed as communication media, so if they are used as communication media, they will have a bad influence on power line channels including various wired and wireless frequencies. Thus, power line channels have no standardized specifications, and are subject to many influences such as on / off switching, motor operation, sparking, and constantly occurring electromagnetic waves and transformers.

Among the various methods for solving this problem, there is a conventional amplifier design and filter design using impedance matching. In addition, design was made by applying physical characteristics of a transformer, matching using a winding ratio, and the like. However, due to the characteristics of the physical devices constituting the power line modem, there are many restrictions on the integration. Particularly, in the design of the power line modem, band loss and distortion of transmission / reception signals occur due to the influence of a filter and the like. However, the conventional power line modem has been limited to compensate for the loss of such a channel.

Korean Registered Patent No. 10-1238071 (Registered on February 21, 2013) Korean Registered Patent No. 10-0595639 (registered on June 23, 2006) Korean Registered Patent No. 10-1007322 (Registered Jan. 4, 2011) Korean Registered Patent No. 10-1501248 (Registered on Mar. 4, 2014)

The present invention has been made to solve the problem of signal distortion caused by the conventional power line modem, and it is an object of the present invention to minimize the signal distortion caused by passing through a bandpass filter of a broadband power line modem through a channel equalizer, And to provide a coupling transformer of a broadband power line modem coupled with a channel equalizer that allows for improved characteristics.

In order to achieve the above object, a coupling transformer of a broadband power line modem according to the present invention receives a PLC signal from a transmitting terminal of a power line modem performing a PLC, couples the PLC signal to a power line, And a PLC signal received from a power line to a receiving end of a power line modem, the coupling transformer including a capacitor C and a resistor RL are connected to the transmitting and receiving ends of the PLC signal of the coupling transformer, And a channel equalizer formed of an LRC resonant circuit connected to the inductor L and the inductor L are coupled to each other to minimize channel loss by compensating for signal distortion occurring when the power line signal is transmitted and received in the power line modem.

The equalizer comprises two or more parallel-connected LRC series circuits in which a capacitor C, a resistor R and an inductor L are serially connected to each other so that a signal loss occurring in a cutoff frequency band of a pass band frequency To compensate.

Here, it is preferable that the equalizer is connected to two or more of the PLC signal transmitting end and the receiving end of the coupling transformer in parallel, respectively.

When two or more filters are connected to the PLC signal receiving end of the coupling transformer and an OP-APM for amplifying the signals is connected, the primary equalizer is connected to the input terminal of the OP-AMP connected between the filters The secondary equalizer may be connected to an output terminal of a filter that receives a signal from the OP-APM connected to the primary equalizer and outputs the filtered signal to compensate for signal distortion.

Meanwhile, the transmission line of the power line modem is provided with a PLC DSP chip (Digital Signal Processor) chip for controlling the operation of a power line modem that performs power line communication (PLC) A BPF (Band Pass Filter) for passing a signal of a band to be transmitted; and an LDA (Line Driver Amplifier) for amplifying the PLC signal and transmitting the amplified PLC signal to the coupling transformer. The receiving end of the power line modem includes the coupling transformer An LNA (Low Noise Amplifier) for lowering the noise figure included in the power line signal transmitted through the LNA 60, a BPF (Band Pass Filter) for removing noise from the signal passing through the LNA 60 to pass the signal band, And an AGC (Auto Gain Control) circuit for adjusting the level of the signal and transmitting it to the PLC DSP chip.

The coupling transformer of the broadband power line modem according to the present invention has a channel equalizer circuit incorporated therein to minimize distortion caused by passing through a filter of a broadband power line modem, thereby improving communication quality. In addition, it is possible to minimize the number of elements of the power line modem used for the broadband power line communication, and to integrate with the coupling transformer.

1 is an overall configuration diagram of a power line modem to which the present invention is applied;
FIG. 2 is an overall circuit diagram of a power line modem to which the present invention is applied;
3 is a circuit example in which an equalizer is applied to a coupling transformer having a differential structure according to the present invention,
4 is an example of an equalizer circuit coupled to a coupling transformer in accordance with the present invention,
5 is a conceptual diagram of an equalizer coupled to a coupling transformer according to the present invention to compensate for signal loss due to a filter of a power line modem,
Figure 6 shows an example of a circuit in which an equalizer according to the invention is coupled between filters.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of a power line modem to which the present invention is applied, and FIG. 2 is an overall circuit diagram of a power line modem.

As shown in FIGS. 1 and 2, the power line modem includes a PLC DSP chip 10 serving as a microcontroller, a BPF 20 and an LDA 30 disposed in a transmitting terminal for transmitting a PLC signal, A coupling transformer 40 and an HPF 50 for loading on a power line and an LNA 60, a BPF 20 and an AGC 80 disposed at a receiving end to receive a signal.

The PLC DSP (Digital Signal Processor) chip 10 is a Digital Engine of a power line modem. The PLC DSP chip 10 is provided with a DAC (Digital-to-Analog Converter) And output as an IFFT (Inverse Fast Fourier Transform) output signal.

The BPF 20 is a transmission filter of the power line modem. The BPF 20 separates the noise band and the signal band of the signal output from the DAC of the PLC DSP chip 10 to block the noise band, .

The LDA 30 is a circuit for amplifying a signal to transmit a power line communication signal to a power line. The LDA 30 adjusts a gain value of the signal to generate a signal As shown in FIG.

The coupling transformer 40 is a transformer that performs coupling to load a PLC signal on a power line of 220 V. The coupling transformer 40 functions as an isolation between the transmitting end, As shown in FIG.

The HPF 50 is a filter that passes a signal of a frequency equal to or higher than a reference frequency. The HPF 50 generates a current due to a voltage difference between two different phases (R / S / T and N phases) So that they are not connected to each other so as to prevent the device from being broken, but serve to pass only signal components.

The LNA (Low Noise Amplifier) 60 provided at the receiving end serves as a buffer for transmitting the received signal to the ADC input terminal of the PLC DSP chip 10, which is a low noise amplifier for lowering the noise figure.

The band pass filter (BPF) 20 of the receiving end removes noise from a signal input to the receiving end through a power line channel and passes only a signal band. An AGC (Auto Gain Control) And the gain of the received signal is adjusted to a predetermined size so that the ADC of the PLC DSP chip 10 can detect the optimum resolution.

In the power line modem having the above-described configuration, the transmission / reception signal of the modem is distorted due to the frequency characteristics of the designed filter.

In the present invention, a channel equalizer is designed and coupled to the coupling transformer 40 of the power line modem so as to minimize the band loss of the power line channel by improving the signal distortion. The channel equalizer improves the characteristics of the signal at the cutoff frequency caused by the filter of the power line modem. In other words, the loss caused by the characteristics of the device at the cutoff frequency of the power line modem filter is not linear, especially above 50% of the loss at this cutoff frequency. In the present invention, in order to make the cut-off frequency response constant in this part, the frequency loss is minimized by increasing the frequency selectivity through the loss and resonance characteristics using the R, L, and C devices.

3 shows an example of a circuit in which an equalizer is applied to a coupling transformer having a differential structure according to an embodiment of the present invention.

3, the channel equalizer 90 is connected to the transmitting end and the receiving end of the coupling transformer 40, respectively. In the embodiment of the present invention, the transmitting end and the receiving end of the coupling transformer 40 are connected to a primary equalization And the second and third equalizers are connected in parallel to compensate for signal distortion occurring in two cutoff frequency bands according to the bandpass. If only one cutoff frequency exists in the transmitting and receiving ends of the coupling transformer 40, only one equalizer 90 can be connected, and if there are three or more cutoff frequencies, three or more equalizers 90 are connected in parallel It is possible.

FIG. 4 illustrates an example of an equalizer circuit coupled to a coupling transformer according to an embodiment of the present invention. The equalizer circuit according to the present invention includes a capacitor C and a resistor R, And an inductor L connected in series or a resonant circuit in which the LRC series circuit is connected in parallel to compensate for signal distortion in the cutoff frequency band so that the linearity of the signal can be maximized.

The LRC series circuit constituting the equalizer 90 exhibits a resonance characteristic, which means a frequency selection function that allows a specific signal to pass but not the other. When these LRC series circuits are connected in parallel, the resonance frequency of the LRC series resonant circuit is made two, and the frequency selectivity is increased by using the HPF cutoff frequency of the BPF 20 and the resonance phenomenon at the LPF cutoff frequency.

These equalizer circuits vary depending on the overall use band of the power line modem, and even if the bandwidth increases, more than three can be connected in parallel because they operate independently.

FIG. 5 illustrates a concept in which the equalizer 90 according to the embodiment of the present invention compensates for a signal loss due to a filter of a power line modem.

5 (a) shows a signal passing through an ideal filter. In the ideal filter, the frequency of the out-of-band is cut off and only the frequency of the in-band is passed in a rectangular pulse form .

5B shows a signal form passing through the actual BPF 20. The signal passing through the actual BPF 20 filter is formed between the out band and the in- The signal loss occurs near the cutoff frequency.

5C shows a signal form passing through the BPF 20 to which the equalizer 90 according to the present invention is applied. The equalizer 90 includes a band out of band of the BPF 20, The signal loss occurring near the cutoff frequency formed between the in-band and the in-band is minimized through the frequency resonance to pass the signal of the pass band in a form close to the ideal rectangular pulse.

6 shows an example of a circuit in which an equalizer 90 according to an embodiment of the present invention is coupled between filters.

6, a plurality of filters for filtering a signal transmitted from the coupling transformer 40 may be provided at a receiving end of the power line modem. An OP-AMP for amplifying a signal is installed between the filters . The equalizer 90 according to the present invention is installed at the input terminal of the OP-AMP connecting the filters to compensate for the distortion of the signal passing between the filters. Also, the equalizer 90 is installed at the output end of the filter, It is possible to compensate for the distortion of the signal. That is, when equalizer circuits R, L, and C are connected in series, X _L = X _C Resonance occurs at the resonance condition. Since the two reactance components are canceled by 0dl at the resonance, the impedance has only the resistance component, so that the resistance is minimized and the current becomes the maximum. Therefore, in this resonance frequency band, the passband signal is passed close to the ideal linearity, so that the band loss can be minimized.

As described above, the channel equalizer 90 coupled to the coupling transformer 40 of the power line modem according to the present invention compensates for the signal distortion caused by passing through the filter through the frequency resonance phenomenon, thereby minimizing the band loss. Also, since the channel equalizer 90 according to the present invention has a simple structure and is directly coupled to the coupling transformer 40, the size of the power line modem can be made small, and the performance can be improved.

It is to be understood that the present invention is not limited to the above-described embodiment, and that various modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the appended claims. Of course, can be achieved.

10: PLC DSP chip (Power Line Communication Digital Signal Processor Chip)
20: Band Pass Filter (BPF)
30: Line Driver Amplifier (LDA)
40: Coupling Transformer
50: HPF (High Pass Filter)
60: Low Noise Amplifier (LNA)
70: Band Pass Filter (BPF)
80: AGC (Auto Gain Control) circuit
90: Equalizer

Claims (5)

The PLC signal is received from the transmitting end of the power line modem (PLC) that performs the power line communication (PLC), and the PLC signal is supplied to the power line by carrying out the coupling to load the PLC signal on the power line. 1. A coupling transformer of a power line modem for transmitting,
The PLC signal transmitting end and the receiving end of the coupling transformer 40 are connected to a channel equalizer having a resonance circuit in which two or more LRC series circuits in which a capacitor C, a resistor R and an inductor L are serially connected, (90) are connected to each other to compensate for a signal loss occurring in a cutoff frequency band of a passband frequency,
When two or more filters are connected to the PLC signal receiving end of the coupling transformer 40 and an OP-APM for amplifying a signal is connected, the primary equalizer is connected to the input terminal of the OP-AMP connected between the filters And the second-order equalizer is connected to an output terminal of a filter for receiving and filtering a signal from an OP-APM connected to the first-order equalizer to compensate for signal distortion.
delete delete delete The method according to claim 1,
(PLC) chip (Digital Signal Processor) chip 10 for controlling the operation of a power line modem performing power line communication (PLC), and a PLC signal processor A BPF (Band Pass Filter) 20 for passing a signal of a band to be transmitted by blocking the noise, and an LDA (Line Driver Amplifier) 30 for amplifying the PLC signal and transmitting the amplified PLC signal to the coupling transformer 40 And,
The receiver of the power line modem includes an LNA (Low Noise Amplifier) 60 for reducing a noise figure included in a power line signal transmitted through the coupling transformer 40, A band pass filter (BPF) 20 for passing a signal band through the signal band and an AGC (Auto Gain Control) circuit 80 for adjusting the level of the received signal and transmitting the signal to the PLC DSP chip 10 A coupling transformer for a powerline modem.

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