KR100963016B1 - An apparatus for binary digital phase shift keying and quadrature digital phase shift keying carrier signal recovery - Google Patents

Abstract

The present invention relates to a digital phase shifter and quadrature phase shifter carrier signal recovery apparatus using a hybrid coupler and a six-terminal phase correlator element.

In the present invention, the PSK carrier signal reconstructing apparatus receives a two-phase shift signal and outputs a first output signal and a second output having a 90 ° phase difference from the input two-phase shift signal. A first element for distributing and outputting the signal; A reflection coefficient generating element that receives the first and second output signals and reflects the reflection coefficient with a predetermined magnitude and outputs it to the first element; And a phase compensator for compensating and outputting the phase value of the third output signal of the first element by −90 °.

In addition, the digital quadrature phase shift type carrier signal recovery apparatus includes: a six-terminal phase correlator for receiving a quadrature phase shift type signal; And a first and second reflection coefficient generator for reflecting the first, second, third, and fourth output signals of the six-terminal phase correlator to the six-terminal phase correlator by reflecting the first, second, third, and fourth output signals with a constant magnitude. It is composed.

Hybrid Coupler, Phase Shift, Restoration, Carrier

Description

TECHNICAL APPARATUS FOR BINARY DIGITAL PHASE SHIFT KEYING AND QUADRATURE DIGITAL PHASE SHIFT KEYING CARRIER SIGNAL RECOVERY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital phase shift carrier recovery device. In particular, a digital phase shift and quadrature carrier signal having a low phase error with respect to fluctuations in input frequency and miniaturized and stabilized carrier synchronization circuits and a simple structure It relates to a restoration device.

Phase Shift Keying (PSK) is one of the modulation methods for remote transmission of digital information signals.Its performance is relatively better than Amplitude Shift Keying (ASK) and Frequency Shift Keying (FSK). Excellent, but structurally more complex than other methods.

As a method of transmitting an information signal to be transmitted through a digital phase shift method (PSK) and receiving the transmitted information signal, a coherent phase having the same frequency as that of the carrier signal of the transmitted information signal and having a synchronized phase Use a coherent reception method.

Here, in order to recover the carrier signal, a multiplier method or a Costas circuit method mainly composed of a frequency multiplication circuit such as a modulation order of a transmitted information signal, a narrowband filter, and a phase locked circuit (PLL) is mainly used. Digital frequency recovery and phase locked circuits are implemented.

The carrier signal recovery circuit includes a frequency signal source used as a carrier signal source such as the frequency domain of the transmitted information signal, and the frequency signal source is a voltage controlled oscillator (VCO), and the carrier signal frequency of the transmitted information signal. It is operated in the area. The voltage controlled oscillator is easily configured in a relatively low frequency band, but is composed of an expensive circuit in a high frequency region or a relatively complex frequency multiplication circuit.

Referring to FIG. 1, a conventional digital phase shift carrier signal recovery method is as follows.

1 is a diagram illustrating a structure of digital phase shift carrier signal recovery according to the prior art.

As shown in FIG. 1, in the multiplication method of the carrier signal restoration method according to the related art, when a phase shift keying signal PS105 is input, the input phase shift modulation signal 105 After passing through the bandpass filter 101, it passes through the multiplication circuit 102. In this case, the modulation component included in the phase shift modulation signal 105 is removed while passing through the multiplication circuit 102.

Thereafter, the phase shift modulated signal multiplied by the multiplication circuit 102 is input to the phase synchronization circuit 103. In this case, the multiplied phase shift modulated signal is phase locked while passing through the phase synchronization circuit.

The phase-locked multiplied phase shift modulated signal is input to the frequency division circuit 106 and output as a signal 107 having a frequency of a carrier signal.

The phase synchronization circuit 103 requires a voltage control element 104 which is a frequency generating source of higher order components.

On the other hand, the Costas synchronous method is the same as the multiplication method in principle, but requires a digital voltage controlled oscillator.

The voltage controlled oscillator is composed of a circuit having the same frequency domain as that of the carrier signal, and has a structure as shown in FIG.

2 is a configuration diagram of a voltage controlled oscillator of a carrier signal recovery apparatus.

As shown in Fig. 2, the oscillation circuit 202 generates an oscillation signal having a fundamental frequency. Here, the frequency and the phase of the oscillation signal are synchronized and output by the variable capacitor element 201 (204). The output oscillation signal is collected by the frequency multiplication circuit 203 and output (205). The variable capacitor element 201 has a variable capacitor size according to a voltage.

At this time, if the frequency of the carrier signal is increased, a voltage controlled oscillator in the high frequency region is required.

However, the voltage controlled oscillator in the high frequency region is expensive, and the circuit itself has a problem that the size thereof increases due to a complicated structure.

In addition, as the control circuit for controlling the voltage controlled oscillator in the high frequency region is complicated, there is a problem that it is difficult to implement and operate the control circuit.

In addition, in the conventional phase shift carrier signal recovery structure, there is a problem that the electrical performance of the synchronization frequency and phase of the carrier signal restored by the configuration and the performance of the phase synchronization circuit (PLL) is affected.

The present invention has been made to solve the above problems, a simple structure that does not require a voltage-controlled oscillator element and a phase synchronization circuit, which is a frequency signal generation component of the carrier recovery circuit, and a compact and stabilized carrier synchronization circuit and input frequency It is an object of the present invention to provide a digital phase shift carrier signal recovery apparatus having a low phase error with respect to the variation of.

In order to achieve the above object, the digital two-phase shift carrier signal recovery apparatus according to the present invention, receiving a two-phase shift signal, the first output having a phase difference of 90 degrees out of the input phase shift signal A first element which divides and outputs a signal and a second output signal; A reflection coefficient generating element that receives the first and second output signals and reflects the reflection coefficient with a predetermined magnitude and outputs it to the first element; And a phase compensator for compensating and outputting the phase value of the third output signal of the first element by −90 °.

It is preferable that a said 1st element is a 90 degree hybrid coupling group.

The phase of the reflection coefficient preferably has a phase value and an inverse phase value of the phase shift signal.

A digital quadrature phase shift type carrier signal recovery apparatus according to the present invention includes a six-terminal phase correlator for receiving a quadrature phase shift type signal; And first and second reflection coefficient generators for reflecting the first, second, third, and fourth output signals of the six-terminal phase correlator to the six-terminal phase correlator to reflect the first, second, third, and fourth output signals with a constant magnitude. .

The six-terminal phase correlator is preferably composed of one power divider and three 90 ° hybrid couplers.

The phase of the reflection coefficient preferably has a phase value and an inverse phase value of the quadrature phase shift signal.

Such a digital phase shift carrier signal recovery apparatus according to the present invention is a carrier signal recovery structure of a two-phase shift and quadrature phase shift using a hybrid combiner and a six-terminal phase correlator element for coherent reception demodulation, There is an effect that it is possible to provide a structure that does not require a voltage controlled oscillator and a phase synchronizing circuit which is a frequency signal source of the prior art.

Therefore, the present invention can easily implement and operate a low cost simple carrier signal reconstruction device.

In addition, the present invention can be extended to the carrier signal recovery apparatus of the higher order mode phase shift method through the carrier signal recovery apparatus of the two-phase and quadrature phase shift method according to the present invention.

Hereinafter, a preferred embodiment of a digital phase shift carrier signal recovery apparatus according to the present invention configured as described above will be described in detail with reference to the accompanying drawings.

However, the scope of the present invention is not limited to the following examples, and various modifications can be made by those skilled in the art without departing from the technical gist of the present invention. . In addition, the terms or words used in the specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors properly define the concept of terms in order to best explain their invention in the best way. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle to be possible.

Figure 3 is a principle diagram of the two-phase shifted carrier signal recovery according to the present invention, Figure 4 is a block diagram of a temporary example of the digital two-phase shifted carrier signal recovery apparatus according to the present invention.

As shown in Fig. 4, a temporary example of the digital phase shift key carrier signal recovery apparatus according to the present invention is a phase shift method in the device for recovering a binary phase shift keying (BPSK) carrier signal. A first element receiving the signal 307 and dividing the input phase shift signal 307 into a first output signal 308 having a 90 ° phase difference and a second output signal 309 and outputting the same; 304); A reflection coefficient generating element 305 which receives the first and second output signals 308 and 309 and reflects the reflection coefficient with a predetermined magnitude and outputs it to the first element 304; And a phase corrector 306 for compensating and outputting the phase value of the third output signal 310 of the first element 304 by −90 °.

Preferably, the first device is implemented as a 90 ° hybrid coupler, and receives a phase shift type signal 307 as a first output signal 308 and a second output signal 309 having a phase difference of 90 °. Distribute and print

The reflection coefficient generator 305 is connected to the output terminals of the first output signal 308 and the second output signal 309, and receives the first and second output signals 308 and 309 to have a predetermined magnitude. Reflected by the reflection coefficient of and re-outputted to the first element (304). In this case, it is preferable that the phase of the reflection coefficient has a phase value and an inverse phase value of the phase shift signal.

The phase corrector 306 compensates the phase value of the third output signal 310 of the first element 304 by −90 ° to output the digital phase shift carrier signal 311. That is, the output signal 311 of the phase corrector 306 is a restored carrier signal having a phase shift value compensated for the phase shift signal 307 and having a constant phase value.

Referring to the operation of the digital phase shifter carrier signal recovery apparatus according to the present invention implemented as described above in detail as follows.

First, the scattering coefficient [S] hyb of the 90 ° hybrid coupler 304 is expressed by Equation 1 below.

[Equation 1]

Yiwi sangpyeon this manner when referred to the input signal 307 of the signal b _in, 90 ° hybrid coupler 304, first and second output signals (308, 309) is the reflection coefficient of the reflection coefficient generating device (305) Γ _l of e is reflected by ^jφ and input to the 90 ° hybrid coupler 304. At this time, the output signal 310, that is, the third output signal (Pb) of the output terminal of the 90 ° hybrid coupler from the equation (1) is the same as the equation (2).

[Equation 2]

When the magnitude of the reflection coefficient is constant in Equation 2, the signals 308 and 309 reflected through the reflection coefficient generating element 305 may not be included in the input phase shift signal 307 according to the phase value of the reflection coefficient. The phase value is constantly shown in the third output signal 310 of the output terminal of the 90 ° hybrid coupler 304.

As described above, the third output signal 310 having a constant phase value is reproduced by the phase compensator 306 as an output signal 311 having a phase in line with an I-channel (In-phase channel).

Here, when the load of the reflection coefficient generating element 305 is open and short-circuited, the phase value of the output signal 311 of the phase compensator 306 is the phase value 301 of the inputted phase shifting signal 307. , 302 and the reflection coefficient generating element 305 to generate the reflection coefficient having the phase relationship 303 as shown in FIG. 3, the output signal 311 of the phase compensator 306 is the input two-phase shift. The phase shift value of the anti-corrosive signal 307 is compensated for, resulting in a restored carrier signal 311 having a constant phase value.

5 is a principle diagram of a quadrature phase shift type carrier signal recovery according to the present invention, and FIG. 6 is a configuration diagram of a temporary example of a digital quadrature phase shift type carrier signal recovery device according to the present invention.

As shown in FIG. 6, a temporary example of a digital phase shift key carrier signal recovery apparatus according to the present invention is a quadrature phase shift keying (QPSK) carrier signal recovery device. A six-terminal phase correlator 407 receiving a signal 414; The six-terminal phase correlator 407 reflects the first, second, third, and fourth output signals 417, 416, 421, and 420 of the six-terminal phase correlator 407 with a reflection coefficient having a predetermined magnitude. And first and second reflection coefficient generating elements 412 and 413 to be outputted to the first and second reflection coefficient generating elements.

The six-terminal phase correlator 407 is composed of one power divider 408 and three 90 ° hybrid couplers 409, 410, and 411, and receives a quadrature phase shift signal 414.

The first and second reflection coefficient generators 412 and 413 are connected to output terminals of the first and third output signals 417 and 416 and output terminals of the second and fourth output signals 420 and 421, respectively. The reflection is reflected with a constant reflection coefficient and output to the six-terminal phase correlator 407 again. In this case, the phase of the reflection coefficient preferably has a phase value and an inverse phase value of the quadrature phase shift type signal.

The six-terminal phase correlator 407 receives the reflected first and third output signals 417 and 416 and the second and fourth output signals 420 and 421, and one power divider 408. And a phase shift value of the quadrature phase shift mode signal 414 via the three 90 ° hybrid couplers 409, 410, and 411, and outputs a restored carrier signal 415 having a constant phase value.

Referring to the operation of the digital quadrature phase shift type carrier signal recovery apparatus according to the present invention implemented as described above in detail.

Scattering factor parameters [S] _{six of} three 90 ° hybrid couplers 409, 410, and 411 constituting a six-terminal phase correlator 407 for carrier signal recovery of a quadrature phase shift keying (QPSK) signal are Equation 3

&Quot; (3) "

From Equation 3, terminal 5 (414) and terminal 6 (415) are input terminals, and terminal 1 (417), terminal 2 (420), terminal 3 (416), and terminal 4 (421) are configured as output terminals. In this case, the phase difference between the output signals of the output terminals 416, 417, 420, and 421 based on the signals input to the input terminals 414 and 415 has an in-phase or 90 ° and 180 ° relationship.

The reflection coefficient generating elements 412 and 413 having the same reflection coefficient are connected to the terminal 1 417, the terminal 3 416, and the terminal 2 420 and the terminal 4 421, respectively. The signal reflected from the terminal is output to the terminal 5 (414) and the terminal 6 (415).

First, when the digital quadrature shift signal is input ( p _in ) to the terminal 5 (414), the output signal output to the terminal 6 (415) is expressed by the following equation (4).

[Equation 4]

Here, P _{6 (1,3)} and P _{6 (2,4)} are terminals 1 (417) and 3 (416), and the signals input from the terminals 2 (420) and 4 (421) are reflected terminal Normalized power output to 6 (415), where Γ _l1 e ^{j φ1} and Γ _l2 e ^{j φ2} are at terminal 1 417 and terminal 3 416, and terminal 2 420 and terminal 4 421 Reflection coefficient.

It can be seen from Equation 4 that when the reflection coefficients of the terminals are the same, the output signals of the terminal 6 415 are represented in the same form. That is, the digital quadrature phase shift signal input to the terminal 5 414 is output to the terminal 6 415 in the form as shown in Equation 5 according to each terminal reflection coefficient.

[Equation 5]

Here, if the magnitude of the reflection coefficient is constant, the phase value of the digital quadrature phase shift signal 414 input according to the reflection coefficient phase values of the terminal 2 420 and the terminal 3 421 is constant at the terminal 6 415. Appears. That is, when the loads of the reflection coefficient generators 412 and 413 are open and short, the phase values 401 and 401 of the digital quadrature phase shift mode signal 414 to which the phase values of the output signal of the terminal 6 415 are input. When the reflection coefficient generating elements 412 and 413 are set to generate the reflection coefficients having the 402, 403, 404 and the phase generating relations 405 and 406 as shown in FIG. 6, the output signal of the terminal 6 415 is The phase shift value of the input digital quadrature phase shift mode signal 414 is compensated to form a restored carrier signal having a constant phase value.

The carrier signal recovery and carrier signal recovery structures of the two-phase shifted and quadrature phase shifted signals as shown in FIGS. 4 and 6 may be extended to the carrier signal recovery of a higher order mode phase shifted (PSK) transmission signal.

Hereinafter, the performance of the digital out of phase or quadrature phase shift type carrier signal recovery apparatus according to the present invention will be described with reference to FIGS. 7 to 12.

7 is a modulated signal used to evaluate carrier signal reconstruction in the structures of FIGS. 4 and 6, and FIG. 8 is a carrier signal used in a transmitter to evaluate carrier signal reconstruction in the structures of FIGS. 4 and 6.

9 is a carrier signal reconstructed by the proposed structure, and FIG. 10 is a signal that is band-passed using the reconstructed carrier signal using an arbitrary filter.

FIG. 11 is a phase deviation due to glitch, and FIG. 12 is a phase deviation signal band-passed using an arbitrary filter as shown in FIG. 10.

As shown in Figs. 7 and 8, the transmitter carrier signal for digital phase modulation signal generation has an ideal signal to noise ratio.

9 and 10, the reconstructed carrier signals 311 and 415 exhibit signal to noise ratio characteristics of about 65 dBc or more. In addition, the sideband of about 40 dBc generates a signal, but exhibits a relatively good carrier signal recovery characteristics.

It can be seen that the carrier signals 311 and 415 recovered from FIGS. 11 and 12 are continuous waves (CW) having a constant phase value (23.4 °), and the phase deviation due to glitch is good within ± 0.8 °. Carrier recovery signal characteristics are shown.

That is, it can be seen that the present invention works well.

1 is a diagram illustrating a structure of digital phase shift carrier signal recovery according to the prior art.

2 is a configuration diagram of a voltage controlled oscillator of a carrier signal recovery apparatus.

3 is a principle diagram of carrier signal recovery according to the present invention;

4 is a configuration diagram of a temporary example of a digital phase shifter type carrier signal recovery apparatus according to the present invention.

5 is a principle diagram of carrier signal recovery according to the present invention;

6 is a configuration diagram of a temporary example of a digital quadrature phase shift type carrier signal recovery apparatus according to the present invention.

7 is a modulation signal used to evaluate carrier signal reconstruction in the structure of FIG.

FIG. 8 is a carrier signal used in a transmitter to evaluate carrier signal reconstruction in the structure of FIG.

9 is a carrier signal reconstructed by the proposed structure,

10 is a signal that is band-passed through the recovered carrier signal using an arbitrary filter.

11 is a phase deviation by glitch,

FIG. 12 is a band pass phase deviation signal using an arbitrary filter as shown in FIG. 10.

Claims (6)

In this phase shift keying (BPSK) carrier signal recovery apparatus, A first element for receiving a phase shift signal and distributing the input phase shift signal into a first output signal and a second output signal having a 90 ° phase difference; A reflection coefficient generating element that receives the first and second output signals and reflects the reflection coefficient with a predetermined magnitude and outputs it to the first element; And a phase compensator for compensating and outputting the phase value of the third output signal of the first element by -90 °. The method of claim 1, The first element, A digital two-phase shifted carrier signal recovery apparatus, characterized in that the 90 ° hybrid coupler. The method of claim 1, The phase of the reflection coefficient is And a phase shift value and an inverse phase value of the phase shift signal. In an apparatus for restoring a quadrature phase shift keying (QPSK) carrier signal, A six-terminal phase correlator for receiving a quadrature phase shift signal; And first and second reflection coefficient generators for reflecting the first, second, third, and fourth output signals of the six-terminal phase correlator to the six-terminal phase correlator by reflecting the first, second, third, and fourth output signals with a constant magnitude. Digital quadrature phase shift carrier signal recovery device. The method of claim 4, wherein The 6-terminal phase correlator is A digital quadrature phase shift carrier recovery device comprising one power divider and three 90 ° hybrid couplers. The method of claim 4, wherein The phase of the reflection coefficient is And a phase value and an inverse phase value of the quadrature phase shift type signal.

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