JP3949264B2 - Frequency hopping communication system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication system using a frequency hopping (FH) method, and more particularly to a communication system using a low-speed FH method. The present invention relates to a method for transmitting data communication while changing the communication frequency at a low speed.
[0002]
[Prior art]
In general, in a communication system using a low-speed FH system, transmission is performed by switching the carrier frequency at a speed slower than the bit speed of the information signal. That is, a plurality of bits are transmitted by one carrier wave. In such a communication system, on the transmission side, the communication frequency (carrier frequency) is changed (hopped) at a predetermined period, a change pattern is generated, and data is transmitted using this change pattern (hopping pattern). . On the other hand, the reception side is in a standby state at a predetermined carrier frequency, and when the transmission side carrier frequency matches the standby carrier frequency, the transition pattern is captured and FH synchronization is established, and then data reception is performed. ing.
[0003]
[Problems to be solved by the invention]
By the way, the conventional low-speed FH system has a problem that it takes time to capture the shift pattern and establish the FH synchronization because the carrier frequency shift speed is lower than the transmission speed.
[0004]
In addition, as described above, in the conventional low-speed FH method, since it takes time to establish the FH synchronization by capturing the shift pattern on the receiving side, the initial transmission data may be damaged. In order to prevent malfunctions, transmission data must be stored in storage means such as a memory until FH synchronization is established, and there is a problem of lack of immediacy.
[0005]
An object of the present invention is to provide an FH communication system capable of establishing FH synchronization in a short time.
[0006]
Another object of the present invention is to provide an FH communication system capable of performing immediate communication without damaging initial transmission data.
[0007]
[Means for Solving the Problems]
According to the present invention, a receiving unit and a transmitting unit are provided, a transmission data signal is transmitted from the transmitting unit to the receiving unit by frequency hopping, and the transmitting data signal is received as a received data signal by the receiving unit. in frequency hopping communication system, the to the transmitter, the data signal after the first delivery the second period frequency hopping synchronization signal in the delivery a second period following the period of the first preamble signal in the period And transmitting the preamble signal and the frequency hopping synchronization signal as a transmission preamble signal and a transmission frequency hopping synchronization signal, respectively, at a predetermined carrier frequency in the first and second periods. The transmission carrier frequency is shifted based on a predetermined frequency hopping pattern. Serial data signal is provided with the second means for transmitting as said transmission data signal, the receiver, the transmit preamble signal to the carrier frequency predetermined by changing the carrier frequency as the received carrier frequency And detecting the preamble signal, and when the preamble signal is detected, the received carrier frequency is fixed to the predetermined carrier frequency and the frequency hopping synchronization signal is detected in advance. And a fourth means for reproducing the determined frequency hopping pattern as a reproduction frequency hopping pattern, wherein the third means shifts the reception carrier frequency in accordance with the reproduction frequency hopping pattern to change the transmission data signal. frequency hopping, characterized in that it received as the received data signal Communication system is obtained.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings.
[0009]
The communication system according to the present invention includes a transmission unit shown in FIG. 1 and a reception unit shown in FIG.
[0010]
First, referring to FIG. 1, the transmission unit includes a timing generator 1, a preamble transmission circuit 2, an FH synchronization signal generation circuit 3, a transmission data output circuit 4, a switch 5, a data modulator 6, a frequency shifter 7, And an FH pattern generator 8. The timing generator 1 manages the transmission timing of the preamble transmission circuit 2, the FH synchronization signal generation circuit 3, the transmission data output circuit 4, and the FH pattern generator 8, and the switch 5 controls the switching. The preamble transmission circuit 3, the FH synchronization signal generation circuit 4, and the transmission data output circuit 5 output a preamble signal, an FH synchronization signal, and transmission data, respectively. The FH pattern is output from the FH pattern generator 8, and the frequency shifter 7 hops (shifts) the carrier frequency according to the FH pattern.
[0011]
Referring to FIG. 2, the receiving unit includes a frequency shifter 9, a data demodulator 10, an FH pattern regenerator 11, an FH synchronization detection circuit 12, and a connector 13. The frequency shifter 9 is an FH pattern regenerator. The carrier 11 hops (shifts) the carrier frequency following the carrier frequency shift on the transmission side according to the reproduced FH pattern. The FH pattern regenerator 11 performs the following operations (1) to (3) according to the synchronization detection signal from the FH synchronization signal detection circuit 12 and the preamble reception detection signal from the data demodulator 10.
[0012]
▲ 1 ▼ cyclic in the default state _{(f1 → f2 ... → f n} -1 → f n) in order to change the carrier frequency.
(2) The operation is temporarily fixed in the preamble reception state.
{Circle around (3)} The FH pattern on the transmission side is reproduced according to the synchronization detection signal.
[0013]
Referring to FIGS. 1 and 2, first, switch 5 connects preamble transmission circuit 2 and data modulator 6 by a switch control signal from timing generator 1. Then, the timing generator 1 operates the preamble transmission circuit 2 to transmit a preamble signal from the preamble transmission circuit 2. The preamble signal is supplied to the data modulator 6 through the switch 5, where it is data-modulated to become a preamble modulation signal and sent to the frequency shifter 7. At this time, the timing signal (operation signal) from the timing generator 1 is not supplied to the FH pattern generator 8, and as a result, the frequency shifter 7 does not shift the carrier frequency, and performs preamble modulation at a predetermined carrier frequency. A signal will be sent out. That is, as shown in FIG. 3, in the preamble transmission period, the frequency shifter 7 transmits the preamble modulation signal as a transmission preamble signal at the carrier frequency fk.
[0014]
On the receiving side, when the preamble is not received, neither the synchronization detection signal nor the preamble reception detection signal is supplied to the FH pattern regenerator 11, so the FH pattern regenerator 11 is in the default state. The carrier pattern is cyclically changed. As a result, the frequency shifter 9 scans the carrier frequency. That is, in the preamble reception scan period shown in FIG. 4, the frequency shifter 9 scans the carrier frequency.
[0015]
By transmitting the carrier frequency, the transmission preamble signal is received by the frequency shifter 9, and the preamble signal is detected by the data demodulator 10. When the preamble signal is detected, the data demodulator 10 sends a preamble reception detection signal to the FH pattern regenerator 11. As a result, the operation of the FH pattern regenerator 11 is fixed. As a result, the frequency shifter 9 operates at the carrier frequency indicated by the FH pattern regenerator 11. That is, in the preamble acquisition period shown in FIG. 4, the frequency shifter 9 operates at the carrier frequency (fk) indicated by the FH pattern regenerator 11.
[0016]
In the transmission unit shown in FIG. 1, when a predetermined time elapses, the timing generator 1 controls the switching unit 5 to connect the FH synchronization signal generating circuit 3 and the data modulator 6. Then, the timing generator 1 operates the FH synchronization signal generation circuit 3 to send out the FH synchronization signal. This FH synchronization signal is applied to the data modulator 6 via the switch 5, where it is data-modulated to become an FH synchronization modulation signal and sent to the frequency shifter 7. The frequency shifter 7 transmits an FH synchronous modulation signal at a predetermined carrier frequency. That is, as shown in FIG. 3, the frequency shifter 7 transmits the FH synchronization modulation signal as the transmission FH synchronization signal at the carrier frequency fk.
[0017]
When the FH synchronization signal is transmitted, the timing generation circuit 1 controls the switch 5 to connect the transmission data output circuit 4 and the data modulator 6 and activates the transmission data output circuit 4 as well as the FH pattern generator. 8 is activated. The FH pattern is supplied from the FH pattern generator 8 to the frequency shifter 7, and the frequency shifter 7 starts the carrier frequency shift based on the FH pattern. On the other hand, transmission data is sent from the transmission data output circuit 4 to the data modulator 6 via the switch 5, where it is data-modulated and sent to the frequency shifter 7 as a data modulation signal. As described above, the frequency shifter 7 shifts the carrier frequency in accordance with the FH pattern, and transmits the data modulation signal as a transmission data signal. That is, as shown in FIG. 3, in the data transmission period, the frequency shifter 7 shifts the carrier frequency and transmits a data modulation signal as a transmission data signal.
[0018]
In the reception unit, as a result of the frequency shifter 9 operating at the carrier frequency (fk), the transmission FH synchronization signal is received by the frequency shifter 9 and is converted into an FH synchronization signal by the data demodulator 10. When the FH synchronization signal is detected by the FH synchronization detection circuit 12, the FH synchronization detection circuit 12 gives the synchronization detection signal to the FH pattern regenerator 11. As described above, the FH pattern regenerator 11 reproduces the transmission side FH pattern as a regenerated FH pattern according to the synchronization detection signal, and applies this regenerated FH pattern to the frequency shifter 9. The frequency shifter 9 shifts the carrier frequency according to the reproduction FH pattern, and follows the carrier frequency shift on the transmission side. As a result, the transmission data signal is received by the frequency shifter 9 and demodulated by the data demodulator 10 to become a data signal.
[0019]
When the FH synchronization detection circuit 12 detects the FH synchronization signal, the FH synchronization detection circuit 12 determines that FH synchronization has been established, and connects the output terminal and the data demodulator 19 with the connector 13 turned on. As a result, the data signal is output as received data. That is, in the data reception period shown in FIG. 4, the frequency shifter 9 shifts the carrier frequency according to the reproduction FH pattern (transmission side FH pattern) from the FH pattern regenerator 11 to establish FH synchronization. .
[0020]
【The invention's effect】
As described above, in the present invention, the preamble and FH synchronization signal are transmitted from the transmission side at a predetermined carrier frequency, and after the FH synchronization is established, the carrier frequency shift (frequency hopping) is performed. Therefore, the reception side can receive the preamble and the FH synchronization signal in a short time, and as a result, the FH synchronization can be established quickly and easily even if the frequency shift speed is low. effective.
[0021]
Furthermore, in the present invention, since FH synchronization is established before transmitting transmission data, the initial transmission data is not lost, and it is not necessary to store the transmission data in a memory or the like. There is also an effect that communication can be performed without lack of immediacy.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an example of a transmission unit used in a frequency hopping communication system according to the present invention.
FIG. 2 is a block diagram showing an example of a receiving unit used in the frequency hopping communication system according to the present invention.
3 is a diagram for explaining an operation of a transmission unit illustrated in FIG. 1; FIG.
4 is a diagram for explaining an operation of a reception unit illustrated in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Timing generator 2 Preamble transmission circuit 3 FH synchronous signal generation circuit 4 Transmission data output circuit 5 Switcher 6 Data modulator 7 Frequency shifter 8 FH pattern generator 9 Frequency shifter 10 Data demodulator 11 FH pattern regenerator 12 FH Synchronization detection circuit 13 connector

Claims (5)

In a frequency hopping communication system comprising a receiving unit and a transmitting unit, transmitting a transmission data signal from the transmitting unit to the receiving unit by frequency hopping, and receiving the transmission data signal as a received data signal in the receiving unit, wherein the transmission unit, first sending a data signal after sending the frequency hopping synchronization signal in sending the preamble signal a second period following the period of the first said second period in the first period And a predetermined frequency hopping after transmitting the preamble signal and the frequency hopping synchronization signal as a transmission preamble signal and a transmission frequency hopping synchronization signal, respectively, at a predetermined carrier frequency in the first and second periods. the data signal by displacing the transmission carrier frequency based on the pattern Serial is provided with second means for transmitting a transmission data signal,
In the receiving unit, a third means for detecting the preamble signal by receiving the transmission preamble signal using the predetermined carrier frequency as the reception carrier frequency by changing the carrier frequency, and detecting the preamble signal Then, a fourth means is provided for reproducing the predetermined frequency hopping pattern as a reproduction frequency hopping pattern when the received carrier frequency is fixed to the predetermined carrier frequency and the frequency hopping synchronization signal is detected. The frequency hopping communication system is characterized in that the third means shifts the reception carrier frequency in accordance with the reproduction frequency hopping pattern and receives the transmission data signal as the reception data signal . 2. The frequency hopping communication system according to claim 1 , wherein the first means includes a preamble transmission circuit that generates the preamble signal, a frequency hopping synchronization signal generation circuit that generates the frequency hopping synchronization signal, and the data signal. A transmission data output circuit for outputting the data, and selecting the preamble signal in the first period, selecting the frequency hopping synchronization signal in the second period, and selecting the data signal when the second period elapses. Selection means for outputting as a selection signal, wherein the second means modulates the transmission carrier frequency with the selection signal to form a modulation signal, and the second period has passed in advance. a frequency hopping pattern generator for outputting a determined frequency hopping pattern, said predetermined et al Frequency hopping communication system characterized by a transmitting frequency shifter to shift the transmission carrier frequency in accordance with the frequency hopping pattern. 3. The frequency hopping communication system according to claim 2 , wherein the selecting means selectively connects the preamble transmission circuit, the frequency hopping synchronization signal generation circuit, and the transmission data output circuit to the data modulator. And controlling the switch to connect the preamble transmission circuit and the data modulator in the first period and to activate the preamble transmission circuit and to generate the frequency hopping synchronization signal generation circuit in the second period. Connecting the data modulator and starting the frequency hopping synchronization signal generating circuit, connecting the transmission data output circuit and the data modulator after the second period, and starting the transmission data output circuit And a timing generation circuit for starting the frequency hopping pattern generation circuit. Frequency hopping communication system according to claim. 3. The frequency hopping communication system according to claim 2 , wherein the third means receives the transmission preamble signal by changing the carrier frequency and using the predetermined carrier frequency as a reception carrier frequency. And a data demodulator that detects the preamble signal from the transmission preamble signal and outputs a preamble detection signal, wherein the fourth means sets the received carrier frequency in advance in response to the preamble detection signal. A frequency hopping pattern regenerator having a predetermined carrier frequency, receiving the transmission frequency hopping synchronization signal by the reception frequency shifter, obtaining the frequency hopping synchronization signal by the data demodulator, and The fourth means includes detecting the frequency hopping synchronization signal and detecting the synchronization detection signal. Is provided with a frequency hopping synchronization detection circuit for outputting said frequency-hopping pattern regenerator regenerates a frequency hopping pattern, wherein the predetermined response to the synchronization detection signal as the reproduction frequency hopping pattern, the receiving frequency frequency hopping shifter is characterized by providing said received data signal to receive the transmission data signal by displacing the received carrier frequency as the received data signal according to the reproduction frequency hopping pattern to said data demodulator Communications system. 5. The frequency hopping communication system according to claim 4 , wherein the receiving unit includes a connector for connecting the data demodulator and an output terminal in response to the synchronization detection signal. Frequency hopping communication system.

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