JPS5910059A - Automatic frequency control system - Google Patents

Abstract

PURPOSE:To need no special pilot signal when a phase shift keying modulated wave is received, by impressing the output of an integrator to a voltage control oscillator in the form of a frequency error signal to keep the frequency at a fixed level for the output signal of a frequency converter. CONSTITUTION:The signal of a non-modulated part is extracted through a narrow BPF9 which transmits the frequencies of the non-modulated part. The signal converted into the DC voltage after the wave detection carried out by a wave detector 10 is compared with the threshold value through a voltage comparator 11 to obtain a pulse signal having a certain time width of the non- modulated part. while this pulse signal exists, the frequency information showing a frequency error of the output of a frequency discriminator 12 is integrated by a sample holding type integrator 13 to obtain the DC voltage proportional to the frequency error. This voltage undergoes the sample holding through the integrator 13 and is applied to a voltage control oscillator VCO14. Thus the frequency of the VCO14 is controlled so that the output of the integrator 13 is set at 0 to obtain the output signal of a fixed frequency for a frequency converter 8.

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a phase shift key ink (hereinafter referred to as P, SK) modulated wave of time division multiple access communication (hereinafter referred to as TDMA) which has an unmodulated part. The present invention also relates to an automatic station ei number control (hereinafter referred to as AFC) system of PSKf harmonics that arrive in bursts to 100 receiving stations.

(b) Prior art and problems Conventionally, it is technically difficult to directly apply AFC to the received PSK modulated wave, so there are few practical examples. ing.

1 is a block diagram of a conventional AFC circuit using pilot signals, and FIG. 2 is a signal arrangement diagram in the case of FIG. 1.

In the figure, 1 is a frequency converter, and 2 is a bandpass r-wave converter (hereinafter referred to as BP).
3 is a frequency discriminator, 4 is a low-pass P wave filter (hereinafter referred to as LPF), 5 is a pressure control oscillator (hereinafter referred to as VCO), 6 is a PSK modulated wave, 7#-i , indicating the pilot signal - 5CPC of Sjangle Channel
In systems with low bit rates (e.g., 32 bits/second, 62 bits/second), such as 1G carrier, the frequency fluctuations of the local transmitter of the satellite and the receiving station are affected by the Since the carrier wave regenerator may not be able to track, the specific station always transmits the pilot signal 7 as shown in Figure 2, so that the frequency fluctuations caused by the local oscillators of the satellite and the receiving station do not move relative to each other, and The eight receiving stations are designed to provide signals with no frequency fluctuations. This method'! This will be explained below using FIG. 1 and FIG. 2. A signal as shown in Figure 2 is frequency-converted by a frequency converter 61 using the frequency of No. 1g of the VCO 5, a pilot signal 7 is taken out by a BPF/, a frequency disparity is discriminated by a frequency discriminator 3, and an LPF 4 is used. The DC voltage is set to 1 through the VCO 5, and the frequency discriminator 3
The VCO 5 is controlled so that the output becomes 0. As a result, the output signal of the frequency converter 1 is kept constant between the pilot signal 7 of the signal as shown in FIG. This eliminates the need for the subsequent regenerator, especially the f←transmission regenerator, to track fluctuations in the center frequencies of the satellite and the receiving local oscillator.

However, with this method, Hiroshi's frequency band that contains the pilot signal and Seiriki are deadly, and the A Hazuru band and "(
This is a drawback in systems where both r and force are strongly restricted.

Recently, 800 bits/second to 16 Mbits/second OuukiTl)MA communication system has been used. In this case as well, it is difficult to track the frequency change of the local oscillator of the satellite and the receiving station during demodulation at the receiving station, especially when using the q-transmission regenerator, so it is necessary to apply AFC. If the pilot signal on the ml side is used for one cycle, there will be a drawback that the wave number (fT) and gravity for sending the pilot signal will be steep.

(c) Purpose of the invention The purpose of Akira Hontaku is to eliminate the above-mentioned drawbacks.
The purpose of this invention is to provide an AFC method that does not necessarily require a special pilot signal when receiving a PSK wave with a

(d) Structure of the Invention In order to achieve the above object, the present invention converts the frequency of the received PSK1 button skin using the output signal of the VCO using a frequency converter, and discriminates the frequency-converted signal using a frequency discriminator. The signal is intermittently integrated by an integrator using No. 1a extracted by the means for extracting the non-modulated part of the PSK modulated wave,
The main feature is that the output of the converter is applied as a frequency error signal to the frequency υi convergence control +llIfumiko of the VCU to keep the frequency of the output 16cm of the wave number converter constant.

(e) Embodiments of the Invention Each embodiment of the present invention will be explained below with reference to the drawings. iAL 3 figure it AFCIIJ of the embodiment of the present invention
It is a block diagram of Iigo.

In the figure, 8 is a frequency converter, 9 (yo + < IJ F, l (J
HA(ri skin device, 11 is pressure Hiei device, 12 is 1・”・j wave 4
13 is a sample and hold type integrator, 14 is V
Indicates CO.

Q's work will be explained below. Received PSK 1. l・ηji him
, j is mixed with the output signal of the VCO 14 in the wave number converter 8 to perform frequency conversion. The frequency of this signal is discriminated by the frequency discriminator 12, but the PS which is modulated by random No. 18
The K harmonic wave has no incoming wave J, and there are 5 υ. However, in TDMA"PSK Rikishikiji, at the end of the same Jυ1 of the carrier wave regeneration circuit, there is a burst υ41 after the burst 1 I.
Hl (K non-modulated 1st river number is 1iil 1rt,'l-.In other words, in this additional modulation part, V11^1 wave number R, h14 can be set to 14 at the output of the discriminator 12 at frequency 4. On the other hand, the part that appeals to people) is resistant to skin ←! 1I with a narrow fluorescence range
PF9 takes out the accuracy of the bullet 51"!1 part. This B)) Output No. 16 of F9 is detected by the detector/receiver lO, and No. 9, which has become a direct pressure, is F-2 ratio V device 11
A pulse signal of a certain time [1] of the 4 parts of the thermal formula is obtained by the threshold value [if the specific pressure is calculated from the pressure of the pressure]. If the frequency information indicating the frequency error is divided by the sample-hold type divider 13 (first, the target current pressure proportional to the dark wave number error is removed). VC (I'j of J14), 7111 is input to the oppression (goods) terminal. Anti-4 Father Yurikiki No 1 Introducing his figure transformation f: Is the output signal of straddle 8 constant?
゛CC operation is performed.

(f) Effects of the Invention As explained in detail above, according to the present invention, it is possible to activate the FCAFC without changing the pilot signal. This system has the effect of making it possible to achieve a high level of efficiency, since it is possible to reduce the sieve quality and reduce the sieve quality by reducing the number of sieves and outputs.Furthermore, there is no system down due to an abnormality in the station transmitting the pilots l, j→I, so it is possible to achieve a high rate of output.

[Brief explanation of drawings]

Figure 1 is a block diagram of the automatic frequency side circuit using the conventional Pilot 1G, No. 21.7.1614
The signal arrangement diagram for the 1st district, Figure 3 is the fruit on the Δ・original side〃1
This is block 1Δ of the automatic frequency control circuit of 4 fishing. In the figure, 1 and 8 are cylindrical number transformers, 2 and 9 are cans (somewhat bad f''), 3.12 are frequency discriminators, 4 is 1 range, Y4, Σ, and 5.゜14Vi' pressure control transmitter, 7 is the pilot's 1st direction, 6 is the phase shift keying change wave, 1 (
H bow, chivalry ~ 匍. Reference numeral 11 indicates a pressure ratio analyzer, and reference numeral 13 indicates a sample-hold type phase separator.

Claims (1)

[Claims] Receives a phase shift key ink modulated wave with a non-modulated part 1
8, the phase shift key ink modulation wave is frequency-converted by a frequency converter using the output signal of the voltage control excavator, and the frequency-converted signal is discriminated by a frequency discriminator. The signal extracted by the means for extracting the love A part of the modulated wave is divided into parts by an integrator, and applied to the frequency side f4J terminal of the voltage controlled oscillator as an output full frequency error signal of the integrator, An automatic frequency control method characterized by keeping the frequency of the output signal of the frequency converter constant.