JPS60107955A - Reference carrier regenerating circuit - Google Patents

Abstract

PURPOSE:To miniaturize and simplify the circuit constitution by switching a phase locked loop for continuous wave and a reference carrier regenerated circuit. CONSTITUTION:A branch circuit 1 divides a 2-phase PSK signal, the result is detected by phase detectors 2a, 2b, discriminated by discriminators 3a, 3b and converted into a binary digital signal. The signals are synthesized by an EX- NOR4 via a logical circuit 14, filtered by a low pass filter 5, a voltage controlled oscillator is controlled and the result is branched by a 0-pi/2 branch circuit 7. When an external control signal A is at ''HI'' level, a phase locked loop is constituted and when ''LO'', a carrier regenerating circuit is constituted.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a reference carrier regeneration device for a two-phase PSK signal wave using a digital multiplication type Costa Sloose, and particularly relates to a reference carrier wave regeneration device for a two-phase PSK signal wave at the time of carrier wave regeneration.
se Ambjguity) removal.

[Prior art]

Two-phase PS using conventional digital multiplication type Costas loop
There was a standard carrier wave regenerator for K signal waves as shown in FIG. In the figure, (1) is the signal branching circuit (hereinafter the first
This is called a branching circuit. ), (2a) and (2b) are the first. Second
The phase detectors (3a) and (3b) are the first. The second discriminator, (4) is an Ex-NOR logic circuit, and (5) is a low-pass filter.

[6] is a voltage controlled oscillator (hereinafter referred to as VOO), (7
) is a 0-π/2 branching circuit (hereinafter referred to as a second branching circuit).

).

Next, the operation will be explained. The signal to the two-phase P8 is divided into two by the first branching circuit (1), and the first signal is divided into two by the second branching circuit (7).
6) together with the output of at's phase shift detector (2a) Ic, second
The signal is phase-shifted by π/2 in the second branching circuit (7).
(Along with the output of 10Fi+, the second phase detector (2b)
are input respectively.

1st, 2nd (DR phase liquid wave device 2a) (2j))
As shown in Fig. 2 (a), each outputs a signal according to the phase difference θ between the two input signals, and the output of the second phase detector (2b) outputs a signal B proportional to the field θ. Output. Each of the two analog output signals A obtained in this way
, B. 1st. 2 in the second discriminator (3a) (3b)
Figure 2(b)
As shown in , each rectangular phase ratio f! has a period of 2π. 5!
Characteristic output signal 0. Get D. These output signals O0D
By calculating the exclusive OR in the NOR logic circuit (4), the output signal C, l) is
An output signal E having a rectangular wave phase comparison characteristic with twice the number of repetitions is obtained. This phase comparison characteristic has two phase stable points (phase attraction points) between a phase difference of 2π. From this, the phase difference between the two-phase PSK signal detected by the first and second phase detectors (2a) (211) K and the v(]0 output has the phase comparison characteristic shown in Fig. 2 (C). When controlling the oscillation frequency of V(10!6) by emitting a phase error signal,
From the two-phase PSK signal wave to the pace node (Ba5eban)
d) In order to demodulate data, it is necessary to reproduce the reference carrier wave for coherent detection. Therefore, when transmitting data using a two-phase PSK signal wave, a continuous wave for carrier wave recovery is set before the data transmission part, and a reference carrier wave for synchronous detection with the required phase to accurately KvlfJI4 baseband data is set. Need to play. The conventional two-phase P8 signal wave reference carrier regeneration device using a digital multiplication type Costas loop has a phase comparison characteristic with two stable points between the phase difference of 2π, so when the reference carrier is regenerated, the regenerated carrier wave is It is pulled into a point by one of the stable points of 211M.

It becomes impossible to always reproduce the reference carrier wave of the required phase. h So-called phase ambiguity occurs. In order to eliminate this phase ambiguity, a unique word is inserted between the carrier ['') raw part and the data transmission part of the 2-phase PSK signal wave.
A unique word detector (Un
igue Word 1) Is it necessary to add “elector”? There are 2. From this, when using the conventional reference carrier regeneration device using the digital multiplication type Costa Sloose, the demodulator for the two-phase PSK signal wave has the configuration shown in FIG. In Figure e, (8) is a signal branching circuit, (9) is a bit timing regeneration circuit that extracts the pit timing necessary for waveform shaping of the baseband waveform from the signal wave from the two-phase P8, (II is the two-phase 1) A baseband extraction circuit that decodes the baseband data from the 2411ps + < 1yS signal by performing transverse wave/waveform shaping on the 8K signal. (
a reference carrier regeneration circuit for regenerating the subcarrier; 0 is a unique word detector that detects a unique word and emits an ambiguity removal signal when there is a two-phase ambiguity;
al is an ambiguity removal circuit that removes phase ambiguity if it exists.

Therefore, in the past, a unique word detector and an ambiguity removal circuit were required in the demodulator. By switching the phase-locked loop for continuous waves and the reference carrier regeneration circuit for signal waves to the two-phase P8, a reference carrier regeneration circuit that can always eliminate phase ambiguity is provided.

[Embodiments of the invention]

FIG. 4 shows an embodiment of the invention. (1) to (7) are completely the same as the conventional device described above.

The butterfly ◆ is an OR logic circuit, which manually inputs the output of the second identification circuit (3b) and the external control signal A, and converts the output signal to 13X.
-NO Output to logic circuit (4).

When the carrier wave [1] is small, the transmission m+ is a continuous wave having an identified phase of π/4 defined as a carrier wave regeneration signal. At this time, the 4th subcarrier regeneration circuit is 0 le 1 pleasure circuit a4
Control III added to V(]0:6) by setting the external velocity control Goku's power to the °Fti'' level.
The output of the second identification circuit (3b) is added as a signal. As a result, the virtual quasi-carrier regeneration circuit becomes a phase-locked loop having a rectangular phase comparison characteristic with a period of 2π as shown in Fig. 2(b), and the two phases are pulled into the phase of π/4, which is the only valid point. . The signal for carrier wave regeneration is 0) L logic circuit 4's external control No. 1g A input ', LO'
By setting the level to V O (J F6), a control signal of the rectangular phase comparison characteristic E with period π shown in FIG.
This becomes a quasi-carrying wave regeneration circuit for signal waves, and the reference carrier wave for reproducing the 4-phase PSK signal wave is regenerated at a fixed phase. In this way, the present invention By using the reference carrier wave reproducing device according to the above, it is possible to reproduce the reference carrier wave without phase ambiguity without additional equipment such as a unique word detector, and the signal wave demodulator for the two-phase P8 can be simplified as shown in Fig. 5. becomes possible. In FIG. 5, (8) is a signal branching circuit, and (9) is a bit timing recovery circuit.

al is a baseband extraction circuit, and QO is a reference carrier recovery circuit.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to always reproduce a carrier wave without phase ambiguity without requiring an additional device such as a unique word detector, and
It also becomes possible to downsize and simplify the signal wave demodulator.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing a reference carrier regeneration circuit for a two-phase PSK signal wave using a conventional digital multiplication type Costa Sloose, Figure 2 is an operating waveform diagram of Figure 1, and Figure 3 is a conventional J↓
A block diagram of a two-phase P8 signal demodulator when using a quasi-carrier regeneration circuit, FIG. 4 is a block diagram showing an embodiment of a two-phase PSK signal wave reference carrier regeneration circuit according to the present invention,
FIG. 5 shows a two-phase PSK signal wave recovery fJ? when using a certain jφ carrier wave regeneration circuit according to the present invention. 4i is a block diagram. In the figure, (1) is a signal branching circuit. (2a) (2b) is the t-th, second phase detector, (3a
)(:+b) is the first. The second discriminator, (4) is gX-N
ot is also a logic circuit, (5) is a low-pass filter, (6) is V(+Q), (71 is a 0-π/2 branching circuit, (8) is a signal branching circuit, (9) is a pit timing regeneration circuit, gif
i baseband extraction circuit, aυ is reference carrier recovery circuit,
θ is a unique word detector, (I3 is a phase ambiguity removal circuit, and 04 is an OR logic circuit. In the figures, the same or corresponding parts are indicated by the same reference numerals.◎ Agent Masu Oiwa Figure 1 Figure 3r4 Figure 4

Claims (1)

[Claims] An oscillator having an oscillation frequency close to the carrier frequency of a two-phase PSK signal and capable of controlling the oscillation frequency;
a first branching circuit that divides the K signal into two two-phase PSK signals that are in phase with each other; and a second branching circuit that divides the oscillation wave of the oscillator into two oscillation waves, one of which has a phase shift of π/2 with respect to the other. 2 divided into two by a branching circuit and the first branching circuit.
In phase P8, detect the phase difference between one of the signals and the oscillation wave whose phase is shifted by π/2 from the input oscillation wave among the oscillation waves divided into two by the second branching circuit.#! 1 phase detector and the 2-phase P divided into two by the first branching circuit.
8, a second phase detector for detecting the phase difference between the other of the signals and the input oscillation wave and the oscillation wave in the same phase among the oscillation waves divided into two by the second branching circuit button; The analog signal is converted into a binary digital signal by outputting a positive predetermined voltage when the output signal of the first phase detector is above a predetermined value, and outputting a negative predetermined voltage when the output signal is below a predetermined value. a first identification circuit, a second identification circuit that converts the output signal of the second phase detector into a binary digital signal, and a digital signal output from the first identification circuit and the second identification circuit; An EX-NOR logic circuit which outputs a signal having twice the number of repetitions of the signal by taking an altruistic logical sum on the digital No. 48 outputted from the identification circuit. , in the reference carrier regeneration circuit, which applies the output of the EX-NO logic circuit to the oscillator via a low-pass filter to control its oscillation frequency, and extracts the reference carrier from the oscillator; The digital signal output from the second identification circuit and the external control signal are ORed between the identification circuit and the EX-NO logic circuit, and the output is input to the 1 (X-NOR logic circuit). Let 01Lr
#A reference carrier regeneration circuit characterized by being provided with an f8 logic circuit.