JPH0683278B2 - FSK signal radio wave transmitter - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention provides an FSK signal as a frequency modulation signal (that is, an individual carrier signal corresponding to data to be transmitted, one for each predetermined period from a plurality of individual carrier signals having a predetermined frequency corresponding to a predetermined character or code, respectively. The present invention relates to a device for selecting a signal and transmitting as a radio wave a signal obtained by serially connecting the selected individual carrier signals). In particular, an appropriate transmission circuit for a short distance transmission, a long distance transmission, etc. The present invention relates to a transmission device configured without changing. In the following figures, the same reference numerals indicate the same or corresponding parts. In addition, logic or level “High”, “Low”,
"1" and "0" are simply described as "H", "L", "1", and "0".

[Prior art]

First, a conventional technique will be described with reference to FIGS. FIG. 8 shows the structure of this type of transmission circuit, and FIG.
The signal waveform of each part in the figure is shown. Further, FIG. 7 shows the resonance characteristics of the antenna circuit, in which the vertical axis is the antenna transmission voltage and the horizontal axis is the input frequency. Next, the configuration and operation of FIG. 8 will be described with reference to FIG.
1 (11, 12) is an individual carrier signal oscillating circuit, which continuously oscillates individual carrier signals F1, F2 (Fig. 9 (1), (2)) of predetermined frequencies (called individual carrier signal frequencies) f1, f2, respectively. To do. The individual carrier signal frequencies f1 and f2 correspond to predetermined characters or codes, for example, "0" and "1".
Reference numeral 3 denotes a modulation signal output circuit, and a serial signal (called a modulation signal) M (9th modulation signal) consisting of "H" or "L"("0" or "1") representing serial data to be transmitted at predetermined time intervals To. (3) is output. Both AG1 and AG2 are AND gates. When the modulation signal M is "H", the former gate AG1 opens the gate to allow the individual carrier signal F1 to pass, and the latter gate AG2 closes the gate to prevent signal passing. . On the other hand, when the modulation signal M is "L", the former gate AG1 blocks the signal passage, and the latter gate AG2 passes the individual carrier signal F2. OG1 is an OR gate and AND gate AG
The individual carrier signals F1 or F2 that have passed 1 or AG2 are serially connected and output as the original transmission signal FM0 (FIG. 9 (4)) as a frequency modulation signal. This original transmission signal FM0 is applied to the antenna circuit 6 via the buffer block BF1. The antenna circuit 6 includes a transmitting antenna L0 and a resonance capacitor C0.
It is configured as a series resonance circuit with the antenna transmission signal FM1 as a voltage (current) in the antenna circuit 6.
Is amplified into a sinusoidal signal as shown in FIG. 9 (5) and transmitted to the outside as a radio wave from the transmitting antenna L0. This method uses two individual carrier signals of frequencies f1 and f2, respectively.
Since the original transmission signal FM0 composed of F1 and F2 is amplified by using one resonance (antenna) circuit 6, as shown in FIG. The individual carrier signal frequencies f1 and f2 are set at positions slightly apart from this peak with the resonance frequency f0
The amplification characteristics for the two frequencies f1 and f2 are made uniform. The resonance frequency f0 is the same as the inductance and the capacitance of the transmitting antenna L0 and the resonance capacitor C0, respectively, Given in.

[Problems to be Solved by the Invention]

However, there is no problem if the frequencies f1 and f2 used as the frequencies of the individual carrier signals can be used close to each other and near the peak of the resonance characteristic, but in the application mainly the present invention, the frequency f1 of the individual carrier signals is , f2 is a relatively low value such as 375 KHz and 500 KHz, and the frequency ratio f2 / f1 is 1.3 times, and the transmitter must be miniaturized. Since L must be used, it is difficult to try to resonate at a high Q value using a resonance circuit common to the frequencies f1 and f2 under such conditions. On the other hand, the magnitude of the Q value, that is, the magnitude of the voltage across the transmission antenna L is related to the reach of radio waves. Therefore, it is absolutely necessary to increase the voltage across the transmission antenna for long-distance applications. That is, if the conventional transmission circuit as shown in FIG. 8 is used as it is, a high Q value cannot be obtained in the intended use of the present invention, so that there is a problem that high-reliability over a long distance becomes difficult. An object of the present invention is to provide an output section for an individual carrier signal (that is, a selected individual carrier signal) selected for each predetermined period via a modulation signal, individually for each individual carrier signal, and an antenna circuit common to this individual output section. , Or by providing a transmitter to which an individual antenna circuit is connected, the frequencies f1 and f2 (where f2> f1) of the individual carrier signals forming the FSK signal are low and the frequency ratio f2 / f1 is large. Even in the case, the short-distance and long-distance switching communication can be performed only by switching the configuration of the antenna circuit without changing the configuration of the basic circuit for transmission.

[Means for solving problems]

In order to achieve the above object, in the present invention, carrier signals (individual carrier signals F1 to FN) of a predetermined frequency (individual carrier signal frequencies f1 to fN) corresponding to predetermined characters or codes, respectively.
N) oscillating and outputting a plurality of individual carrier signal oscillating means (1,11
To 11N, 16,17) and individual carrier signals (F1 to FN), one for each predetermined period (To), a selection signal for selecting the individual carrier signal according to the data to be transmitted. Modulation selection signal output means (3 and N1, or 3A, or 3 and AG) for outputting (S, S1 to SN)
1 and AG2) and selected individual carrier signal output means (G) which are provided corresponding to each individual carrier signal oscillating means and output the individual carrier signal for a selected period based on the selection signal. , G1〜
GN or 16 and 17) and an FSK signal radio wave transmitting device comprising a common antenna circuit (6) common to a plurality of individual carrier signals and a plurality of individual carrier signals for each selected individual carrier signal output means. Dedicated antenna circuit (7,8) for each one or corresponding to one individual carrier signal among multiple individual carrier signals
It is provided with terminals (41, 42) to which one type of antenna circuit selected from the three types of antenna circuits for AM (7 or 8) is connected. Further, the common antenna circuit includes an antenna coil (Lo) commonly provided for a plurality of individual carrier signals, and individual capacitors (C1 to CN) individually provided for each individual carrier signal.

[Action]

Selection as individual carrier signals selected for a predetermined period based on the modulation signal Selection for outputting individual carrier signals FS1 and FS2 Short-distance transmission to terminals (41, 42) provided for each individual carrier signal output means In the case, a common antenna circuit (6) that connects the two outputs of the signals FS1 and FS2 by wired OR is connected, and in the case of long-distance transmission, dedicated antenna circuits (7 and 8) that individually transmit the signals FS1 and FS2, respectively. ) Is connected, and when transmitting only one of the signals FS1 and FS2, one AM antenna circuit (7 or 8) is connected to the terminal (41 or 42) corresponding to FS1 or FS2. By simply reconnecting the antenna circuit, it is possible to cope with a desired transmission mode without changing the basic transmission circuit. Further, the common antenna circuit (6) is commonly provided for a plurality of individual carrier signals (11 to 1N), and the antenna coil (Lo) is provided.
And the individual capacitors (C1 to CN) individually provided for each individual carrier signal to improve the matching of the common antenna circuit to each individual carrier signal.

【Example】

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a configuration example when connecting a basic transmission circuit as a first embodiment of the present invention to various antenna circuits, and FIGS. 1 (A), (B), and (C) show short-distances, respectively. The circuit configurations of the transmission mode, long-distance transmission mode, and ASK signal transmission mode are shown below. In addition, FIG. 4 shows the signal waveform of each part in FIG. The individual carrier signal oscillation circuit 1 (11, 12) and the modulation signal output circuit 3 in FIG. 1 are similar to those in FIG.
The individual carrier signals F1 and F2 and the modulation signal M as in (2) and (3) are output. G (G1, G2) in FIG. 1 is a gate element that opens the gate to allow a signal to pass when the selection signal S (S1, S2) is "L", and N1 is a NOT element. The modulation signal M is inverted by the NOT element N1 and becomes the selection signal S1 and is given to the gate element G1, while the modulation signal M is directly given to the gate element G2 as the selection signal S2. Therefore, the gate element G1 passes the individual carrier signal F1 only when the modulation signal M is "H", while the gate element G2 passes the individual carrier signal F1 only when the modulation signal M is "L". As a result, the individual carrier signals selected as shown in FIGS. 4 (5) and 4 (4) are output to the output terminals (referred to as transmission output terminals) 4 (41, 42) of the gate elements G1 and G2 (referred to as selected individual carrier signals). ) FS1 and FS2 appear. The gate elements G1 and G2 are wired output terminals 41 and 42
The output impedance when off is high so that OR connection is possible. In FIG. 1 (A), the transmission output terminals 41 and 42 are wired-OR connected and then connected to the common antenna circuit 6. The resonance frequency f0 of the antenna circuit 6 is determined so as to obtain the relationship as shown in FIG. 7 (A) with respect to the individual carrier signal frequencies f1 and f2. The transmission antenna L0 is small as described above. Since a high Q value cannot be obtained, the configuration of FIG. 1 (A) is used for short distance transmission. Next, in the case of long-distance transmission, as shown in FIG. 1B, the transmission output terminals 41 and 42 of the gate elements G1 and G2 are connected to the individual antenna circuits 7 and 8, respectively. Here, L1 and L2 are transmission antennas, C1 and C2 are resonance capacitors, and when their inductance and capacitance are represented by the same symbols, these values are It is decided to have such a relationship. That is, the antenna circuits 7 and 8 are configured to resonate with the individual carrier signal frequencies f1 and f2, respectively, as shown in the characteristic of FIG. FIG. 1 (C) shows a state in which the transmission output terminals 41 and 42 are cut off, and the antenna circuit 7 as a transmission (resonance) circuit is connected to only one transmission output terminal 41. This circuit
It can be used as a transmission circuit for ASK (amplitude modulation) signals instead of FSK signals, and can also be used for receiving signals with a simple reception circuit. FIG. 2 shows a second embodiment of the circuit configuration of the present invention, which is an example of a method for obtaining resonance characteristics for each of the individual carrier signals F1 to FN while using a common transmission antenna L0. In the figure, 1 (11, 12 to 1N) is an individual carrier signal oscillation circuit similar to 11 and 12 in FIG.
The individual carrier signals F1, F2 to FN of f1 and f2 to fN are output. Each of the frequencies f1 to fN corresponds to a predetermined character or code. G (G1, G2 ... GN) is a gate element similar to G1 and G2 in FIG. 1, and 3A is directly connected to each gate element G to select signal S.
It is a selection signal output circuit for modulation which gives (S1, S2 to SN). The output circuit 3A outputs the selection signals S one by one for each predetermined period To, selects the gate element G corresponding to the serial data to be transmitted, and selects the selected gate element G.
The individual carrier signal is selected from the transmission output terminal 4 (selected one of 41 to 4N) of the individual carrier signal during the above period To.
~ 1 out of FSN). In this case, between the transmission output terminals 41 to 4N of each gate element and the common transmission antenna L0, the resonance capacitors C1 to CN are respectively connected, In other words, each of the resonance capacitors C1 to CN is combined with L0 in series one by one, and series resonance is generated by the frequencies f1 to fN. This method can be made small because it can be configured with one transmission antenna L0, but since each transmission drive circuit (gate element G) has a high output impedance when it is not transmitting, An antenna at the transmission output terminal 4
The voltage across L0 is connected via the corresponding resonance capacitor, and each gate element G must have a high breakdown voltage. For example, if a resonant circuit with Q = 20 is used and it is driven by a power supply voltage of 5V to resonate, 5V will be applied across the antenna L0.
A voltage of × 20 = 100V (PP) will be generated. )
Therefore, if the drive output circuit (gate element G) has a high breakdown voltage, this circuit system can be adopted. Further, in the modulation method using the FSK dual-frequency individual carrier signals F1 and F2 as shown in FIGS. 1A and 1B, the mutual switching timing of the individual carrier signals F1 and F2 depends on the demodulation performance of the receiver. Greatly affect the. That is, as shown in FIG. 5, the individual carrier signals F1, F2 ((1), (2) in the figure) are switched by the modulation signal M ((3) in the figure), but the modulation signal M is set at the switching timing. If it is used as it is, at the time of switching, a pulse having a width (or interval) different from any pulse width (or pulse interval) of the individual carrier signals F1 and F2 is generated like the original transmission signal FM0 in FIG. 5 (4). . A receiver that receives such a signal FM0 causes a spike voltage near this switching time, which causes a problem. FIG. 3 shows a transmitting basic circuit as a third embodiment of the present invention which can solve this problem. That is, the frequency divider 16 which divides the original oscillation frequency f0 into 1 / n to obtain the individual carrier signal frequency f1 and the frequency divider 17 which similarly divides the frequency f0 into 1 / m to obtain the individual carrier signal frequency f2. And
By switching the operation of each frequency device 16 and 17 via AND gates AG1 and AG2 for inputting the modulation signal M as in FIG.
Regardless of the switching time point of the modulation signal M, the frequency f1 changes from the frequency f1 to the frequency f2 and the frequency f2 changes from the frequency f1
It may be configured to change to. FIGS. 6 (1) and 6 (2) respectively show the selective individual carrier signals FS1 and FS2 output from the transmission output terminals 41 and 42 of the frequency dividers 16 and 17 in this way. Modulated signal M
Switching of the individual carrier signal frequency so that the pulse width (pulse interval) at the time of switching will be one of the pulse widths (pulse intervals) of frequencies f1 and f2 even if the switching time changes between the solid line and the dotted line. Is performed. By using such a switching method, it is possible to prevent a sudden signal change such as a spike from occurring in the reception waveform of the receiver.
The S / N ratio can be improved.

【The invention's effect】

According to the present invention, the output means (gate element G, etc.) for each selected individual carrier signal forming the FSK signal, and therefore the transmission output terminal, is provided for each individual carrier signal. It is possible to connect a common antenna circuit for transmission or to connect separate antenna circuits for long-distance transmission, and
By connecting the antenna circuit to only one, it is possible to output the ASK signal instead of the FSK signal, and it is possible to easily change the configuration of the transmission circuit as needed.

[Brief description of drawings]

FIGS. 1, 2, and 3 are block circuit diagrams showing different embodiments of the present invention, FIG. 4 is a waveform diagram for explaining the operation of FIG. 1, and FIGS. Both are waveform charts for explaining the operation of FIG. 3, FIG. 7 is an explanatory view of the resonance characteristic of the antenna circuit, FIG. 8 is a configuration diagram of a conventional circuit, and FIG. 9 is for explaining the operation of FIG. It is a waveform diagram of. 1 (11 to 1N): Individual carrier signal oscillation circuit, 3: Modulation signal output circuit, 3A: Modulation selection signal output circuit, G (G1 to GN): Gate element, N1: NOT element, 4 (41 to 4N) : Transmission output terminal,
6,7,8: Antenna circuit, C (Co to CN): Resonant capacitor, L (L0 to L2): Transmit antenna, 16: 1 / n frequency divider, 17: 1
/ m frequency divider, AG1, AG2: AND gate, F1 to FN: Individual carrier signal,
FS1 to FSN: Selected individual carrier signal, f0: Original oscillation frequency, f1 to f
N: individual carrier signal frequency, M: modulated signal, S (S1 to SN): selection signal, To: period.

Claims (2)

[Claims] 1. A plurality of individual carrier signal oscillating means for oscillating and outputting an individual carrier signal of a predetermined frequency corresponding to a predetermined character or code, and one of the individual carrier signals, one for each predetermined period,
A modulation selection signal output unit that outputs a selection signal for selecting an individual carrier signal according to the data to be transmitted, and a unit provided corresponding to each of the individual carrier signal oscillation units, based on the selection signal. , The selected period,
A selective individual carrier signal output means for outputting the individual carrier signal concerned, and an FSK signal radio wave transmitting device consisting of: provided for each of the selected individual carrier signal output means, common to the plurality of individual carrier signals. An antenna circuit, a dedicated antenna circuit for each of the plurality of individual carrier signals, or an AM antenna circuit corresponding to any one individual carrier signal of the plurality of individual carrier signals is selected from among three types of antenna circuits. An FSK signal radio wave transmission device comprising a terminal to which one type of antenna circuit is connected. 2. A common antenna circuit comprising: an antenna coil commonly provided for a plurality of individual carrier signals; and an individual capacitor individually provided for each of the individual carrier signals. The FSK signal radio wave transmission device as set forth in the first paragraph of the range.