JPS58215156A - Reproducing circuit of carrier wave - Google Patents

Abstract

PURPOSE:To reproduce a reference carrier wave from a 2-phase modulated wave and to realize the share between 4-phase and 2-phase, by providing a switching circuit to one side of an orthogonal control signal system of a costas type carrier wave reproducing circuit which reproduces a reference carrier wave from a 4-phase modulated wave. CONSTITUTION:An operation same as a conventional costas loop is ensured when a switch 13 is closed. When the switch 13 is opened, the output of an adder 12 is equal to the waveform (C) obtained by obtaining a product through a multiplier 10 between the waveform (B) of an LPF4 and the waveform (A) of a comparator 9'. The output of the adder 12 moves to a point (i) and (j) when the digital value is 0 and pi respectively and has the same function to have the synchronism for the phase of a VCO7' since the place where the value 0 cuts is set in the same phase changing direction. Thus the VCO7' is set under a stable phase synchronizing state. A reference carrier wave is reproduced also from a 2- phase modulated wave with the output of the VCO7'.

Description

[Detailed Description of the Invention] Igl Technical Field of the Invention The present invention relates to a digital four-phase <S'r
, Can it be shared for 2-phase and 4-phase phase modulated waves using a Costas type carrier wave regeneration circuit that fully recovers the reference carrier from the phase modulated wave?
Regarding the measured carrier wave regeneration circuit.

Background of the tbl Technology Conventionally, in a digital phase modulation transmission line, it has been almost impossible to completely change the harmonics. However, in recent years, in the field of satellite 'A bonds' where the quality of the transmission path is influenced by weather etc., various compensation methods have been used to switch the transmission speed of the variable harmonic frequency signal (i) depending on the line quality. There is one.

In the digital phase modulation method, 4 phase change and 2 phase change 1
1114=2 Comparing, if the signal band is the same, 4 phases are 2
It is possible to transmit twice as many signal tones as compared to a phase-based method, but in order to obtain the same code error rate, the line quality must be about 3 db better. Therefore, when the line quality is good and the weather is good, one line of signal transmission is performed using four-phase modulation, and when the line quality is poor, such as on rainy days, a two-phase change is performed to ensure communication.

The present invention is designed to restore the receiving side of such a communication system! It is used for II equipment.

tel Conventional technology and problems Digital phase change from W4 wave to standard carrier wave? A so-called Costas type carrier wave regeneration circuit (Costas loop) is known as a regeneration means, and in order to regenerate each of the 4-phase 2 and 2-phase phase modulated waves, the conventional methods shown in Figs. 1 and 2 are used. A dedicated independent circuit was used.

Figure 1 is a block diagram of a conventional 2-phase Costas L-1 circuit; The time of the waveform to explain the stable point of Kosdas I leg in the case of 1000 yards shows the waveform of (1?'+-θO)? Rn
) nonn1. Form k shows, N 4 Figure (・Complete explanation of the stable point of the Costas loop in the case of 21-2 Figures j) At the time of 1,000 yards of the waveform (N ke low v, P wave device (hereinafter '1:l' PF ) 4' output waveform, (R is the comparator 9 small output waveform, (
(-I digit L P P 7' output waveform, fl) is the output waveform of comparator 9', (bow is the output waveform of t calculator 1o, (D digit 1, output waveform of calculator 11, (G digit The output waveform of Add nR% 12 is shown.

(1.l', :'1, 5.5', 1 (1, 11 are detractors, 2, 4, 2', 4' are LPF, 6
, 6' is a loop filter, 7.7' is a voltage controlled oscillator (hereinafter referred to as VCO), 1Ft'h9oz phase shifter, g
, g'H ratio v, 12 indicates the adder.

First, Figure 1 and Figure iA3? The operation of the two-phase Costas I rape will be explained using the following. Two-phase phase modulated wave of input signal 'it m
(tl s'n (Wr tl61) (however, m (11 indicates the amplitude i) and the output of VCO7 Q2SIn(w, (+
θ0), these quadrant calculations are performed in Hayabusa calculator LPF
Signal hum that passed 2 times (11(:o q(θ knee〇〇)
Tokaru. Also, the output of VCO7? 90 degree phase with 90 degree phase shifter 8? Shifted signal 2Cos (w, tl00) and input signal and 1 in multiplier 5? jl-do LPF'4? The output signal is inputted as m(tl 5in(θl-00). When the signal w# of the output of LPF2 and 4 is calculated by 3 in J unit 3, the output signal becomes key S1n 2(θ1-θ0 )
becomes. This signal is passed to the VCO7 via the Lugsirter 6.
In addition to that, the phase difference (θ1-θO) is set to 0-"1Vc
The phase of O7 is completely changed (,1Z,.

In other words, it is a phase locked circuit. m1tlco at this time
It becomes s. The phase difference (θl−θO) of the two-phase phase modulated wave changes from 0 to π depending on the decider I value. This results in m
(11Cos (θI−θO) is the point A in (2) or 0
trIIf tl -T-81n 2 (θ1-00) moves to point C or two points of the mountain. However, since the direction of phase change is the same at point C and two points, VC07i phase synchronization is performed. Even if the phase changes, the VCO7y works in the same way and there is a phase difference (θ1-00). Note that the signal to, 1 of m((l Cos (θ1−θ0))
II) 0. I will judge li)
I have to.

Next, how does the 4-phase Costas loop work using Figure 2 and Figure 4?
explain. The process up to the outputs of LPF2' and LPF4' is the same as in the two-phase cosda loose case. Therefore, LPF'2'
The output waveform of LPF 4' is as shown below, and the output waveform of LPF 4' is as shown in (q).

Are these waveforms compared by all comparators 9' and 9, and are they positive or negative? When determined and output, it becomes a positive and negative rectangular wave shown as tBl(+)). When the product of the rectangular wave signal of the output of the comparator 9' shown in ((-1) and the output signal of T, PF4' of the waveform shown in (-1) is calculated using Tosan G1oVC, the waveform of the signal is Also, (flf of the rectangular wave signal of the output of the comparator 9 shown on the left and the output signal of L P F 2' with the waveform shown on the left)
When calculated using the kI calculator it, the waveform of the signal is as shown in the figure below.When calculated using the adder 12, the waveform of this signal is shown as (0). While the phase of the input signal waveform changes to 2 as shown in , there are four places where ( ) is cut at 90 degree intervals in the direction of the same phase change, such as E, H, G, and 1000. It is converted into DC electrons through the yI?loop filter 6'?V (: 07/
(so that the signal shown at q becomes 0 point) (so that the VCO
The phase of 7' is completely changed. The 4-phase f\γ-phase modulated wave changes depending on the digital value so that the phase difference between the input signal and the output signal of V (207') becomes O,r/2°''+3/2g. Even if the output of the adder 12 shown in q changes to 1, the output of the adder 12 is near E, H, G, and 1000 at π/2 intervals. The same trap works to achieve phase synchronization.VCO7J: Pulls into a stable synchronization phase.In this way, the reference carrier wave is fully regenerated at the output of VCO7'.In addition, the outputs of LPF2' and 41?
The input signal is sent to a 0.1 discriminator circuit (not shown), and depending on whether the input signal is on the + side or on the one side, based on the reference carrier of the output of LPF 2' and 4', depending on the phase difference. Fully modulated digital value? However, the two-phase Kosda loop circuit shown in Figure 1 can only be used for two-phase phase modulation, and the four-phase Kosda loop circuit shown in Figure 2 can only be used for four-phase phase modulation. Tame 4
When phase modulation and two-phase phase modulation are used together, it is necessary to have two circuits, which results in a large and expensive circuit.
One circuit? Since it is used, it has the disadvantage of poor reliability.

(Object of the Invention) In order to eliminate the above-mentioned drawbacks, the purpose of the present invention is to make it possible to use a four-phase Cosdas type carrier wave regeneration circuit also in the case of a two-phase phase modulated wave, thereby making it possible to reduce the size, cost, and reliability. The objective is to provide a carrier wave regeneration circuit with high performance.

te+ Structure of the Invention In order to achieve all of the above objects, the present invention provides a four-phase phase change filter.
By installing the entire switch circuit on one side of the orthogonal control signal system of the Cosdas type carrier wave regeneration circuit that fully regenerates the reference carrier from the i-wave, it is possible to fully regenerate the reference carrier from the two-phase phase modulated wave, making it possible to fully regenerate the reference carrier from the two-phase phase modulated wave. 7) Embodiment of the Invention One embodiment of the present invention will be described below with reference to the drawings.

FIG. 5e is a block diagram of a carrier recovery circuit according to an embodiment of the present invention.

Components in the figure that have the same functions as those in FIG. 2 are indicated by the same symbols.

13ke Suino (pregnant).

FIG. 5 shows a circuit in which a switch 134 is provided between the DW circuit 11 and the adder 612 in the conventional four-phase Costas loop circuit shown in FIG. Therefore, when the [C switch] 3 is in the connected state, it is the same as the conventional 4-phase cosda I control. When this switch 13t is turned off, the output of the adder 12 is
Since the image signal is high from the 3rd side, we will explain it using Figure 4.The case of Figure 2 will be explained, and the output signal of the 3V device 10 shown in the left side will be shifted from its side output. The phase of %VT:07' is controlled such that the signal Th11 is applied to V C ()7' via the boo fielder 6' and the signal shown at the peak becomes the point i. The two-phase modulated wave is divided into human signal and VC by digital value.
The phase difference of the output signal of O7' changes from k to π.

[7] However, in the circuit shown in Fig. 5, the output of the oscillator 12 moves to the glue point (G) in Fig. 4 when it is 0, and to the vicinity of the N point when it is π; Since the direction of change in phase is the same, VC
(17/ phase all synchronization
7'2 Draw into a stable phase rotation state.

By kneading, the reference carrier wave is also reproduced from the two-phase phase modulated wave at the output of VC07'. In addition, whether the output 2o of PF:,",4' is sent to the discrimination circuit, in this case,
When the output of F2' is 10 maximum (phase difference 0) and - maximum (phase difference π), the output of LPF and s' are both (), so input in the case of 10 maximum and -maximum. signal?
The modulated child digital P can be obtained. As described above, when the switch 13 is connected to the carrier wave regeneration circuit for the 4-phase (XT phase-modulated wave), the switch 13 is turned off (if it is inserted between the 2-phase phase modulated waves
The output of the device 12 is as shown in Fig. 4 (arrow), and when the phase of the input signal and the VCO 7' is 0, it moves to the vicinity of the O point when the input signal and the VCO 7' are at the Le point π. Since it is in the same direction, it works in the same way to complete all the phase cycles of the VCO 7' and pull the VCO 7' into a stable phase-equal state.Therefore, it may be done in this manner.

(Button: Effects of the Invention) As explained in detail in 2, the present invention provides a 4-phase Costas-type slave transmission regeneration circuit.It can be used in common with the circuit that fully regenerates the reference carrier wave from the phase modulated wave of the 2-phase, so it can be made smaller and less expensive. This has the effect of realizing high reliability because the circuit scale is large.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a conventional 2-phase Kosda loop circuit, and Figure 2 is a conventional 4-phase Kosda loop circuit. A block diagram of the loop circuit. Figure 3 is a time chart of the waveform that explains all the stable points of the Kostas loop in the case of Figure 1. Figure 4 shows all the stable points of the Costas loop in the case of Figure 2. The Dimechard and WJS diagram of the waveform shown in FIG. In the figure, 1.1', :'1, 5.5', 10.11 are Tosaiki, 2゜4.2', 4' are low-frequency r wave generators, 6, 6' are loop fit radars, 7 .7' is a voltage controlled oscillator, 8,8/ is a 90 degree phase shifter, 9.9' is a comparator, 12 is an adder, 13
Is it a switch? show. ] Connection - Yara-ni

Claims (1)

[Claims] Is it possible to provide a switch circuit on one side of the orthogonal control signal system of a Costas-type carrier wave regeneration circuit that regenerates a reference carrier wave i from a four-phase phase modulated wave, and to use this switch at all locations?Is it possible to regenerate a reference carrier wave from a two-phase phase modulated wave from K? A carrier wave regeneration circuit with all six features