JPS6075158A - Automatic phase control circuit - Google Patents

Abstract

PURPOSE:To quicken the establishment of synchronism by providing a reference voltage generator to keep assuredly the oscillating frequency of a voltage controlled oscillator. CONSTITUTION:A selection circuit 8 selects either the output signal of a loop filter 6 or the output signal of a reference voltage generator 9 depending on the output of a delayed phase modulation wave detection circuit and supplies the selected signal to the voltage controlled oscillator 7 at the inside of a frequency divider 7 as a control voltage input signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic phase control circuit used in a data communication demodulation device, and includes a two-axis detection method for regenerating a reference carrier wave necessary for obtaining a phase modulated wave at t1〒. This paper relates to an improvement of a Zumble value controlled automatic phase control circuit.

Traditionally, for demodulation of phase modulated waves, two reference carrier waves ' It is a well-known fact that sample value type automatic phase control is generally performed to match the phase angle of the modulated wave and the phase angle of the reference carrier wave.

Next, the conventional method will be explained with reference to FIG. In FIG. 1, V, 21 is the input terminal of the phase modulated wave which is the receiving sword,
1 is a phase detector using the subcarrier X(o') as a control signal carrier; 2 is a first baseband waveform signal (X)V;
This is a low-frequency p-wave device for extracting. Reference numerals 101 and 102 each indicate a phase detector using a reference carrier Y (900) as a control signal carrier for extracting a second baseband waveform signal (y) directly connected to the first baseband waveform signal X, and a low frequency It is a p-wave device. 3 and 103 are slice-type first and second level determiners for fully determining phase vectors based on first and second baseband waveform signals, respectively. 4 is a phase control signal generator into which the first and second baseband waveform signals Xp Y k are input as error signals, and the vector signals determined by the first and second level determiners 3.106 are input as control signals. It is. 5 is a sample hold circuit whose sampling interval is the modulation rate Tl, and 6 is a loop filter. A system that inputs the output of the 7-digit loop filter 6 as a phase control signal,
Includes a pressure-controlled oscillator and orthogonal reference carrier waves X, Y
f, a frequency divider for generating. Note that the output signals (JUTX
, OUi'Yi-1: Q appear at the output terminals 22 and 23, respectively, and the baseband signal X, respectively.

The X component of the received vector signal, which is in phase with y,
This is the Y component. In the two-axis detection method having the above configuration, as explained above, the respective in-phase components that are phase-detected on the two axes (X and Y) (projected on the two axes) are used to determine the signal vector, Each component is used to generate a control signal for automatic phase control. These control signals control the oscillation frequency of the voltage-controlled optical oscillator included in the frequency divider 7, and operate so that the phase angle of the phase modulated wave matches the phase angle of the reference carrier wave.

The control voltage characteristics of the voltage-side formation oscillator are as shown in FIG. 2, and the operation of the voltage-controlled optical oscillator is unstable when no long signal is present. 7 Therefore, enter car & nine f1
The free-running frequency of the frequency generator is adjusted near the voltage Vs that is close to the carrier frequency aF's of one wave.

FIG. 3 is a waveform diagram showing the operation of the voltage controlled optical oscillator.

In FIG. 3, (A) is the input modulated wave, point a is the point at which the input starts, and point 0 is the point at which the input is cut off.

(B) shows the AGC output waveform when the signal is output through the automatic phase control l amplifier inside the device, and point b shows the point at which the AGC output waveform always returns to IE. , when there is no signal, it corresponds to the period from 0 point to point a in Figure 3, and this period IC is due to the noise of the transmission line inside the device and the point a in Figure 3 (H). Due to the transient response of the automatic gain control circuit immediately after the application of the modulated wave corresponding to 5 points 1 from 5 to 1, the control voltage ratio of the voltage parallel type oscillator changes from point a to point C in the broken Q section of Figure 3 (C). It is disturbed as shown in shi△V. As a result, as shown in Figure 2, a frequency disturbance of Fs±△f occurs with respect to the voltage of Vs±△V, completely changing the phase angle of the input modulated wave and the phase angle of the reference carrier wave. In order to match
As shown in FIG. 3(D) from point a to point C, a considerable amount of time is required.

As explained in the following two explanations, when there is no signal and immediately after the phase modulated wave is fully applied, the voltage controlled optical oscillator according to the prior art has no control voltage and is in an uncontrolled state, so the oscillator It takes a long time to match the 6r phase angle of the carrier wave oscillation frequency and the phase angle of the phase modulation wave, and it takes a long time to synchronize the automatic phase fttll nQ1 circuit. There was a drawback.

An object of the present invention is to provide a reference voltage generator to maintain the entire oscillation frequency of a voltage-controlled optical oscillator when no signal is input, thereby eliminating all of the above-mentioned drawbacks, and by adding a simple circuit (S" It is an object of the present invention to provide an automatic phase control i+ output circuit which is capable of quickly matching the phase angle of an L-phase modulated wave and the phase angle of a fundamental Yk carrier wave of a voltage-side 1rLII type oscillator.

The (11) components of the present invention include a pair of phase detectors, a pair of low wave detectors, a pair of level determiners, a two-phase control signal generator, a sample and hold circuit, a loop filter, and a reference voltage generator. 2 selection circuit, and a frequency divider including a voltage controlled oscillator.

A pair of phase detectors is used to add a phase changer (Th) as an input, and use the in-phase component and quadrature component of the reference carrier wave as control voltages, thereby performing detection. A pair of low-frequency wave detectors converts the respective outputs of the pair of phase detectors into P waves, and outputs the first and second wave.
This is only for obtaining a baseband signal for direct combustion.

The pair of level discriminators use the first and second direct-fired base hand signals to discriminate the phase vector and obtain a -z.1 vector signal. phase! I
The i control signal generator inputs the first and ε1×2 baseband signals from the pair of low-band P-wave generators as a pair of jl'1 difference signals, and also inputs the pair of baseband signals obtained by the pair of level determiners. The vector signal is used as a control signal to obtain a phase 11iQ control signal.

The sample and hold circuit is for sampling and holding the output of the phase control signal generator.

The loop filter is for filtering the output sound F wave of the sample and hold circuit. The reference voltage generator generates a voltage equal to the standard output of the loop filter for all reference voltages. The selection circuit selects either the output voltage of the loop filter or the output voltage of the reference voltage generator. is a voltage for generating a signal with a wave number of d corresponding to the voltage output from the return circuit!A fi-controlled oscillator is composed of the in-phase component and the complex component of the basic carrier wave. It is a useless item that makes noise.

The present invention will be described in detail below with reference to the drawings.

FIG. 4 shows an embodiment of the automatic phase control circuit according to the present invention.
The numbers 03, 4, 5, 6.7 are the same as in the conventional circuit shown in FIG.

On the other hand, 8 selects either the output signal of the loop filter 6 or the output signal of the pressure generator 9 based on the reference f.
Select the li control signal and send it to the voltage controlled keepsake inside the frequency divider 7. , i voltage input signal; n selection circuit. 9 is a 4■j pressure generator that generates a reference voltage for oscillating the oscillation frequency that is the same as the carrier frequency of the input modulated wave when the voltage-controlled vibrator is not under automatic phase control 1; 1゜ is the input voltage generator; This is a delay circuit for delaying the entire output of the phase-shifted 5'M wave detection circuit by a certain period of time and outputting the output signal as a selection control signal for the 8-selection circuit 8.

As already explained, in the sample value type automatic position A old 1t control circuit, when a phase modulated wave exists as an input signal, a phase 11 control loop is established by the control signal and the control voltage is stabilized, so the voltage fllJ The frequency of the controlled oscillator also follows this and remains stable.

Figure 6 is a timing diagram showing the operation of the voltage-controlled token oscillator in ``41''. In Figure 6, (A) to (1)
) are waveforms having the same meaning as FIGS. 3(A) to (D). tf'; In Figure 4, when there is no input signal, the phase control loop is disconnected and the transmission line 4'
Due to IL sound and 411L sound inside the device, 1ltlJ (Jll signalization, i.e., random noise) of ΔV as shown in 6r"r6 figure CC)
There exists a number component.

Therefore, the frequency of the voltage controlled oscillator changes randomly according to the phase modulation frequency θ, that is, a frequency deviation of Δf from the reference frequency. Therefore, as shown in Figure 5,
The difference between the signal vector synchronized with the moon and summer waves and the carrier wave, that is, the signal vector point corresponding to the phase angle difference between the signal vector and the oscillation frequency of the voltage-controlled wholesale oscillator, rotates at a fairly fast Me. and move. -Also, when one vertical phase modulated wave is input, a disturbance phenomenon occurs. Therefore, as in the case of no signal, the phase angle of the transmission wave rotates at a faster speed with respect to the reception vector, as shown in FIG.

As explained above, 'jlf pressure fill i, j1
When the oscillation frequency of the type 1 oscillator, that is, the reference frequency, has a phase shift with respect to the input phase modulated wave, the phase angle between the reference frequency No. 1a and the input displacement vector rotates at a constant speed, and the As shown in Figure 6 (IJ), synchronization is established by the internal automatic phase 11i1J control circuit, and it takes a long time to get from point a to point C.

Therefore, in the present invention, the fully automatic phase I
Regardless of the control signal of the II+11n circuit, a reference voltage (Vs) is applied to make the voltage-controlled vibrator oscillate at the reference frequency (Fs), and the synchronization is established using the points shown in Figure 6 (G). The purpose is to shorten the distance from d1 to d1. As a means of this, in this type of device the required rate ij
As an essential function, the output signal of the detection circuit is inputted to 44 input terminals and 24 VC, and all waveforms as shown in FIG. 6(E) are input.), 1. I got it with lj child 24. Therefore, the 41st
The input is delayed by a certain period of time by the delay circuit 10 shown in the figure, and the entire waveform shown in FIG. 6(F) is obtained. This is money,
In the quick selection circuit 8 in Fig. 4, it is used as a selection signal, and this causes a constant 6 output that causes disturbance at the time of the p heat signal and immediately after applying human power, or oscillates the reference frequency of the phase modulated wave. The output of the reference voltage (the output of the reference voltage generator 9 in FIG. 4) is selected and supplied to the voltage-controlled token included in the frequency divider 7.

As explained above, according to the present invention, the reference voltage generator ff
:In preparation, standby when no signal is input, automatic phase jllj
By speeding up the establishment of synchronization of the 111 circuits, the preparation time required for demodulating the entire modulation/demodulation unit ('d, i1m) can be shortened, and the efficiency of the entire data transmission system can be improved. .

[Brief explanation of the drawing]

FIG. 1 shows an automatic phase fli! according to the prior art. FIG. 2 is a block configuration diagram showing an example of a control circuit. ↓Figure 2 is a diagram showing the relationship between pressure and frequency of the 'lif pressure i coining type oscillator of Figure 1. FIG. 3 is a timing diagram showing the operation of an automatic phase control circuit according to the prior art. FIG. 4 is a block diagram showing an embodiment of the automatic phase ft1J elevation circuit according to the present invention. FIG. 5 is a vector diagram showing the relationship between the phase modulated wave vector and the oscillation frequency vector of the 11-voltage TTF controlled oscillator. FIG. 6 shows automatic phase adjustment according to the present invention! Timing 1-4 shows operation 1 of the fi control circuit. 1.101・φ・Phase detector 2.102--・Low frequency p wave detector 3.106+1ψ・Level judge 4・-・Phase control signal generator 5 * * @Sample hold circuit 6III・Loop filter 7...・Voltage controlled keepsake 8Il - competition selection circuit? -Reference voltage generator 10...Delay circuit Patent applicant Japan 1 Koki Co., Ltd. Company agent Patent attorney I) Ro Hisashi

Claims (1)

[Claims] a pair of phase detectors for performing detection by adding a phase modulated wave as a receiving power and using the in-phase component and quadrature component of the reference carrier wave as control &'ll'C pressures; and the pair of phase detectors. a pair of low-pass p-wave generators for obtaining first and second orthogonal baseband signals through respective outgoing Kinto waves; and a phase vector using the first and second orthogonal baseband signals. a pair of level determiners for determining the same vector signal and inputting the first and second baseband signals from the phantom low-frequency ρ wave generator as a pair of error signals , by using the pair of vector signals determined by the pair of level determiners as control signals (a phase control signal generator for obtaining the S7 phase control signal and the output of the phase control signal generator). A sample bold circuit for sample bolding, a loop filter for generating the output f:P wave of the sample bold circuit, and a reference voltage that is equal to the output heavy pressure at mark 7 of the loop filter. a second selection circuit for selecting either the output voltage of the loop filter or the output voltage of the reference voltage generator from the open side 1 signal V; a heavy pressure controlled oscillator for generating all the signals of frequencies corresponding to the voltage output from the carrier selection circuit, and a frequency divider for generating a control voltage consisting of in-phase components and quadrature components of the reference carrier wave. The automatic phase control circuit also has all the features.