JP5398212B2 - Wireless communication system - Google Patents

Description

The present invention relates to wireless communication systems that use such a mobile communication system, in particular, the control signals from the call table for the operator to use, via a repeater from the line connection device which is away from the call table transmitted to the base station Te, also relates to the monitoring signal from a base station repeater, the wireless communication system for transmitting a call table through a line connection device.

  In a wireless communication system such as a mobile communication system using a mobile object such as a portable wireless device or an in-vehicle wireless device, communication between the mobile objects is performed via a base station (for example, see Patent Document 1).

Figure 7 is a system configuration diagram showing a conventional example of such a wireless communication _{system, 100 1, 100 2, ......} , 100 n are the base _{station, 101 1, 101 2, ......} , 101 n repeaters, 102 is a relay connection device, and 103 ₁ , 103 ₂ ,..., 103 _n are telephone tables.

In the figure, each base station 100 _1, 100 _2, ......, 100 _n are provided for different areas, the base station 100 ₁ each, 100 _2, ......, 100 _n may, repeater 101 _1, It is connected to the line connection device 102 via 2 ₂ ,..., 2 _n . Also, this line connection device 102, the base station 100 _1, 100 _2, ..., call table 103 ₁ per 100 _n, 103 _2, ..., 103 _n are connected.

Hereinafter, when the base stations 100 ₁ , 100 ₂ ,..., 100 _n are collectively referred to, the base station 100 _i (where i = 1, 2,..., N) corresponds to the base station 100 _i . The repeater and the call desk are called the repeater 101 _i and the call desk 103 _i , respectively.

In the case of wireless communication (call) between mobile units in the same area, a voice signal (that is, a call signal) from a mobile unit (not shown) is transmitted to another mobile unit (not shown) via the base station 100 _i . Alternatively, in the case of wireless communication between mobile units in different areas, the line connection device 102 has base stations 100 _i and 100 _{j in} two respective areas (where j ≠ i and j = 1, 2). ,..., N) are connected, and a voice signal from one mobile unit is received by the base station 100 _i , and the base station 100 _i repeater 1 _i , the line connection device 102, and the repeater 101 _j are connected. It is supplied to the base station 100 _j, transmitted from the base station 100 _j to another mobile.

In such a wireless communication system, a call is also performed between the mobile unit and the telephone desk 103 _i . At this time, a voice signal for an inquiry from a mobile unit is received by the base station 100 _i in the area, and the corresponding telephone table 103 _i is received from the base station 100 _i via the repeater 101 _i and the line connection device 102. It is supplied to the audio signal such as for the response to the inquiry from the call table 103 _i is supplied to the base station 100 _i via the line unit 102 and the repeater 101 _i, to the mobile station that there is such inquiry .

Call table 103 _i also by supplying a control signal to the base station 100 _i in question via the repeater 101 _i for line connection device 102 and applicable to control the base station 100 _i, the base station 100 _i in the example, when such an abnormal situation occurs, in order to notify the call table 103 _i to base station 100 _i corresponds take such a situation, via the repeater 101 _i and line unit 102 from the base station 100 _i Thus supplying the monitoring signal to this call table 103 _i, call table 103 _i monitors the appropriate base station 100 _i.

By the way, at the time of communication between the telephone table 103 _i that supplies such control signals and monitoring signals (hereinafter collectively referred to as control monitoring signals) and the base station 100 _i, between the mobile station and the telephone table 103 _i. There are times when communication is performed. In such a case, the audio signal and the control monitoring signal are transmitted simultaneously between the telephone desk 103 _i and the base station 100 _i . As the transmission method, the control monitoring signal is a DC signal, and the audio signal Transmission system that superimposes this DC signal on, frequency division multiplex transmission system that frequency-division-multiplexes and transmits the audio signal and control monitoring signal, and time-division multiplex transmission that transmits the audio signal and control monitoring signal by time-division multiplexing There is a method.
Japanese Patent Laid-Open No. 10-94029

By the way, 2-wire (2W) or 4-wire (4W) is generally used as a transmission line in a city or an urban area. The use of fibers and the like is increasing, and a transmission method for superimposing and transmitting a direct current cannot be used. Also, in division multiplex transmission method when transmitting time-division multiplexed with the audio signal and the control monitor signal, in the period in which the control monitor signal is transmitted, will be the audio signal is missing, the base station by calling desk 103 _i When there are many control items of 100 _i, the audio signal missing period is further increased, and the quality of the audio signal is deteriorated. Such a problem can be solved by a frequency division multiplex transmission system in which the audio signal and the control monitoring signal are frequency division multiplexed and transmitted.

Here, an example of a frequency division multiplexing transmission system performed between the telephone desk 103 _i and the base station 100 _i will be described with reference to FIG.

In such a frequency division multiplex transmission system, for example, the boundary frequency F _B is set to 2,800 Hz, the frequency band lower than the boundary frequency F _B is set as the transmission band of the audio signal, and the higher frequency side than the boundary frequency F _B. 8A and 8A, when the frequency band (voice band) of the audio signal A is 300 Hz to 3,400 Hz, as shown in FIGS. the boundary frequency by F _B remote high-frequency component of a is cut by LPF (low pass filter). Then, as shown in FIGS. 8A and 8B, the control monitoring signal is frequency-division-multiplexed as a high frequency side signal from the boundary frequency F _B on the high frequency cut audio signal A. Here, the control monitoring signal has a different frequency depending on the type of control / monitoring. In the example shown in the figure, the control monitoring signal is a signal having a frequency of 2,900 Hz as one control monitoring signal CW ₁ , and the other 1 One control monitoring signal CW ₂ is a signal having a frequency of 3,000 Hz, another one control monitoring signal CW ₃ is a signal having a frequency of 3,100 Hz, and another one control monitoring signal CW ₄ is The four types of control monitoring signals CW are signals having a frequency of 3,200 Hz.

Such frequency division multiplexing signal (FIG. 8 (b), (b)), from the call table 103 _i to the base station 100 _i in FIG. 7, or transmitted from the base station 100 _i to the call table 103 _i, the base station 100 _i or the telephone table 103 _i , the audio signal A is extracted by LPF or the like and, as shown in FIGS. 8B and 8B, the received frequency division multiplexed signals (FIG. 8B and FIG. The audio signal A is removed by HPF (high-pass filter) from a)), and each control monitoring signal CW ₁ , CW ₂ , CW ₃ , CW ₄ (hereinafter referred to as BPF (band-pass filter) having respective pass bands is used. Are collectively referred to as a control monitoring signal CW).

In this way, the control monitoring signal can be frequency-division-multiplexed with the audio signal A and transmitted between the telephone desk 103 _i and the base station 100 _i .

By the way, when the control monitoring signal CW is frequency-division multiplexed with the audio signal A in this way, the level (amplitude) of the frequency-division multiplexed signal increases. The type of control of the base station 100 _i by the call table 103 _i is more, also the subject of monitoring by the call table 103 _i at the base station 100 _i be those with more, from the call table 103 _i There are multiple types of control signals sent to the base station 100 _i and monitoring signals sent from the base station 100 _i to the telephone console 103 _i . In addition, a plurality of such control monitoring signals may be transmitted simultaneously from the telephone console 103 _i to the base station 100 _i or from the base station 100 _i to the telephone console 103 _i. There is a problem in that the level of the multiplexed signal increases abnormally, and the receiving side becomes an excessive input state, for example, exceeds its saturation level in an amplifier or the like, causing malfunction. In this case, in order to prevent this, the saturation level of the amplifier may be set sufficiently high, but this requires an expensive and large-sized amplifier.

  An object of the present invention is to eliminate such a problem and control and monitor in a wireless communication system that can avoid an increase in the level of a frequency division multiplexed signal even if there are many control and monitoring signals to be frequency division multiplexed on an audio signal. It is to provide a signal transmission method.

In order to achieve the above object, the present invention controls a base station that performs radio communication with a mobile unit, controls and monitors the base station, and transmits audio signals to and from the mobile unit via the base station. includes a call table for performing communication, and a wireless communication system for communicating multiple control monitoring signals for the control or monitoring of the base station between the base station and the vent story table, said plurality of The control monitoring signal is a plurality of control signals respectively supplied from the telephone desk to the base station or a plurality of monitoring signals supplied from the base station to the telephone desk, and the plurality of control signals or the plurality of control signals are supplied. A monitoring signal is transmitted in a frequency band different from the frequency band of the audio signal, and is multiplexed and transmitted on the audio signal periodically at different timings between the base station and the telephone desk. Special communication It is an.

  According to the present invention, the plurality of control monitoring signals are time-division multiplexed with different frequencies, and further transmitted to the audio signal by frequency division multiplexing. Even at each timing, one control monitoring signal is always frequency-division multiplexed on the audio signal at each timing, and the level of the control monitoring multiplexed signal in which the control monitoring signal is frequency-division multiplexed on the audio signal is excessive. It is possible to handle a large number of control monitoring signals, and to add a circuit with a simple configuration for time division multiplexing compared to the transmission system configuration in the case of the conventional frequency division multiplexing system. In addition, the circuit configuration can be reduced at low cost without complicating the circuit configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a control supervisory signal transmission method in a wireless communication system according to the present invention. FIG. 1 (a) shows the transmission of the telephone table 103 _i and base station 100 _i in FIG. FIG. 7B shows the reception system in the base station 100 _i and the telephone table 103 _i in FIG. 7, respectively, 1 is a clock generator, 2 is a gate signal generator, 3 ₁ , 3 ₂ , 3 _3. , 3 ₄ is an oscillator, 4 ₁ , 4 ₂ , 4 ₃ , 4 ₄ are gate circuits, 5 ₁ , 5 ₂ , 5 ₃ , 5 ₄ are transmission permission gate circuits, 6 is an adder, 7 is a modulator, and 8 is LPF, 9 is an adder, 10 is a transmitter, 11 is a receiver, 12 is an HPF, 13 is an LPF, 14 ₁ , 14 ₂ , 14 ₃ and 14 ₄ are BPFs, and 15 is a demodulator.

  Here, although four types of control monitoring signals to be transmitted and received are described, the present invention is not limited to this, and the present invention can be applied to any number of types of control monitoring signals.

  First, the transmission system shown in FIG. 1A will be described with reference to waveform diagrams showing signals at various parts in FIG. 1A shown in FIG.

In the transmission system of the telephone desk 103 _i and the base station 100 _i in FIG. 1, the frequencies f ₁ , f ₂ , f from the oscillators 3 ₁ , 3 ₂ , 3 ₃ , 3 ₄ are respectively shown in FIG. ₃ and f ₄ continuous waves are generated and supplied to the gate circuits 4 ₁ , 4 ₂ , 4 ₃ and 4 ₄ , respectively. Here, FIG. 2B shows a continuous wave of frequency f ₁ and FIG. 2C shows a continuous wave of frequency f ₂ .

On the other hand, a clock CK having a constant period _TCK shown in FIG. 2A is generated from the clock generator 1 and supplied to the gate signal generator 2. Here, in FIG. 2 (a), the sequential period T _CK control monitor signal CW ₁ clock CK, CW _2, CW _3, has been repeatedly assigned in order to CW _4, 1 period T indicated by t (1) _CK period and assignment period to the control and monitoring signals CW ₁ (called period t (1). other similarly for the period), the period t (2) the allocation period to the control and monitoring signals CW _2, the period t ( 3) is an allocation period for the control monitoring signal CW ₃ , and a period t (4) is an allocation period for the control monitoring signal CW ₄ .

In the gate signal generator 2, the gate signals G ₁ , G ₂ , G ₃ , and G ₄ for the control monitoring signals CW ₁ , CW ₂ , CW ₃ , and CW ₄ corresponding to each allocation period are supplied from the supplied clock CK. Generate sequentially and repeatedly. The generated gate signals G ₁ to the gate circuit 4 _1, gate signal G ₂ is the gate circuit 4 _2, the gate signal G ₃ are gate circuit 4 _3, gate signal G ₄ are are respectively supplied to the gate circuit 4 ₄ . FIG. 2B shows the gate signal G ₁ supplied to the gate circuit 4 ₁ , and FIG. 2C shows the gate signal G ₂ supplied to the gate circuit 4 ₂ , respectively. The timing is shown in accordance with the timing of the clock CK.

In the gate circuit 4 ₁ , every time the gate signal G ₁ is supplied from the gate signal generator 2, the signal from the oscillator 3 ₁ is supplied during the signal period of the gate signal G ₁ (that is, the period t (1) of the clock CK). continuous wave frequency f ₁ is extracted, the intermittent signal CW ₁ of intermittently frequency f ₁ every period of 4T _CK by signal period T _CK 'is supplied to the transmission permission gate circuit 5 ₁ obtained. In the gate circuit 4 _2, every time the gate signal G ₂ continuing from the gate signal generator 2 to the gate signal G ₁ is supplied, the signal period of the gate signal G ₂ (i.e., the period of the clock CK t (2)) Then, a continuous wave of frequency f ₂ is extracted from the oscillator 3 ₂ , and intermittent signal CW ₂ ′ of frequency f ₂ is obtained intermittently at a timing following the intermittent signal CW ₁ ′ by the signal period _TCK every 4T _CK period. is supplied to the transmission permission gate circuit 5 _2, in the gate circuit 4 _3, each of the gate signals G ₃ continuing from the gate signal generator 2 to the gate signal G ₂ is supplied, the signal period of the gate signal G ₃ (i.e. , in the period t (3)) of the clock CK, a continuous wave of a frequency f ₃ from the oscillator 3 ₃ are extracted, intermittently at a timing subsequent to the intermittent signal CW ₂ 'for each cycle of 4T _CK by signal period T _CK An intermittent signal CW ₃ ′ of frequency f ₃ is obtained and the transmission permission gate is obtained. Is supplied to preparative circuit 5 _3, the gate circuit 4 _4, every time the gate signal G ₄ continuing from the gate signal generator 2 to the gate signal G ₃ is supplied, the signal period of the gate signal G ₄ (i.e., the clock CK the period t (4)), the oscillator 3 ₄ continuous wave frequency f ₄ is extracted from the intermittently frequency f ₄ at a timing subsequent to the intermittent signal CW ₃ 'for each cycle of 4T _CK by signal period T _CK Intermittent signal CW ₄ ′ is obtained and supplied to the transmission permission gate circuit 54. In this way, intermittent signals CW ₁ ′, CW ₂ ′, CW ₃ ′, CW ₄ ′ are output in order from the gate circuits 3 ₁ , 3 ₂ , 3 ₃ , 3 _4, and transmission permission gate circuits 5 ₁ , 5 are respectively output. ₂ , 5 ₃ and 5 ₄ .

Here, the intermittent signal CW ₁ ′ output from the gate circuit 4 ₁ is shown in FIG. 2B, and the intermittent signal CW ₂ ′ output from the gate circuit 4 ₂ is shown in FIG. 2C.

Transmission permission gate circuit 5 _1, 5 _2, ..., 5 ₄ are normally closed and, at this time, these transmission permission gate circuit 5 _1, 5 _2, ..., from 5 _4, the control and monitoring signals CW ₁ , CW ₂ ,..., CW ₄ are not output, but when the transmission permission signals SP ₁ , SP ₂ , SP ₃ , SP ₄ are supplied, these transmission permission gate circuits 5 ₁ , 5 ₂ , 5 ₃ , 5 ₄ Is opened and the supplied intermittent signals CW ₁ ′, CW ₂ ′, CW ₃ ′, CW ₄ ′ are output as control monitoring signals CW ₁ , CW ₂ , CW ₃ , CW ₄ .

Here, a transmission permission signal SP ₁ supplied to the transmission permission gate circuit 5 ₁ in FIG. 2 (b), a transmission permission signal SP ₂ supplied to the transmission permission gate circuit 5 ₂ FIG. 2 (c) respectively show ing.

It is those such transmission permission signal _{SP 1, SP 2, SP 3} , SP 4 are supplied when transmitting each control monitor signal _{CW 1, CW 2, CW 3} , CW 4 , and control monitoring signals CW ₁ when sending, the transmission period, the transmission permission signal SP ₁ to the transmission permission gate circuit 5 ₁ is supplied, when transmitting a control monitor signal CW _2, the transmission period, the transmission permission gate circuit 5 ₂ to the transmission permission signal SP ₂ is supplied, when transmitting a control monitor signal CW _3, the transmission period, is supplied transmission permission signal SP ₃ in the transmission permission gate circuit 5 _3, when transmitting a control monitor signal CW _4, the transmission period, the transmission transmission permission signal SP ₄ is supplied to allow the gate circuit 5 _4.

Here, the control and monitoring signals CW ₁ output from the transmission permission gate circuit 5 ₁ in FIG. 2 (b), the control monitor signal CW ₂ output from the transmission permission gate circuit 5 ₂ FIG. 2 (c) respectively show ing.

A signal output from the adder 6 (hereinafter referred to as a multiplex control monitoring signal CW) includes control monitoring signals CW ₁ , CW ₂ , CW ₃ , and CW ₄ having frequencies different from those of f ₁ , f ₂ , f ₃ , and f _4. The time-division multiplexed data is supplied to the adder 9. The multiple control monitoring signal CW is shown in FIG.

On the other hand, when this transmission system is the transmission system of the communication console 103 _i (FIG. 7), the audio signal A inputted and modulated by the modulator 7 is an LPF 8 having a cutoff frequency of f _CUT (FIG. 8). Is supplied to the adder 9 and is added to the multiplex control monitoring signal CW from the adder 6. Further, when this transmission system is the transmission system of the base station 100 _i (FIG. 7), the received audio signal A is supplied to the LPF 8 whose cutoff frequency is f _CUT (FIG. 8) and band-limited. Thereafter, it is supplied to the adder 9 and added to the multiplex control monitoring signal CW from the adder 6. The output signal of the adder 9 is a signal obtained by frequency-division-multiplexing the multiplex control monitoring signal CW with the audio signal A on the higher frequency side than the audio signal A, and is transmitted from the transmitter 10.

  FIG. 3 is a schematic spectrum diagram showing frequency division multiplexed signals (hereinafter referred to as control monitoring multiplexed signals) for each period of the multiplexed control monitoring signal CW and the voice signal transmitted from the transmission system shown in FIG. .

In the figure, here, as an example, the frequency band of the audio signal A is set to 300 Hz to 2,800 Hz, and the frequencies f _{1 to} f ₄ of the control monitoring signals CW _{1 to} CW ₄ are respectively set as in the conventional example of FIG. ,
f ₁ = 2900 Hz f ₂ = 3,000 Hz
f ₃ = 3,100 Hz f ₄ = 3,200 Hz
And Also, the control monitoring multiplexed signal for each period t (1) to t (4) in FIG. 2A is shown, but here, the control monitoring signals CW ₁ and CW ₂ are transmitted and the control monitoring signal is transmitted. CW ₃ and CW ₄ are not transmitted.

Therefore, when the control monitoring signals CW ₁ and CW ₂ are transmitted, if the audio signal A is also transmitted, in this period t (1), the control monitoring signal of f ₁ = 2,900 Hz is added to the audio signal A. CW ₁ is frequency-multiplexed and transmitted, and in the next period t (2), the control monitoring signal CW ₂ of f ₂ = 3,000 Hz is frequency-multiplexed and transmitted to the audio signal A. In the next two periods t (3) and t (4), the control monitoring signals CW ₃ and CW ₄ assigned to them are not transmitted, but if they are also transmitted, f ₃ is transmitted in the period t (3). = control monitor signal CW ₃ of 3,100Hz is, the control and monitoring signals CW ₄ of f ₄ = 3,200 Hz is transmitted is frequency division multiplexed to each audio signal a in the period t (4).

  Thus, in this embodiment, the control monitoring signal is transmitted to the audio signal by frequency division multiplexing when the audio signal is transmitted, but there are a plurality of control monitoring signals to be transmitted simultaneously. However, at each timing, one control monitoring signal is always frequency-division multiplexed on the audio signal, and the level of the control monitoring multiplexed signal in which the control monitoring signal is frequency-division multiplexed on the audio signal may be excessive. Absent. Therefore, a large number of control monitoring signals can be handled. Further, compared to the transmission system configuration in the case of the conventional frequency division multiplexing system shown in FIG. 8, only a simple configuration circuit for time division multiplexing is added, and the circuit configuration is not complicated. In terms of cost, it can be configured at low cost.

Next, the receiving system provided in the base station 100 _i and the telephone desk 103 _i in FIG. 7 shown in FIG. 1B will be described.

A transmission signal from the transmission system shown in FIG. 1A is received by the receiver 11 and supplied to the HPF 12 and the LPF 13. When this received signal is the audio signal A or the control and monitoring multiplexed signal, the audio signal A is extracted by the LPF 13, and when this reception system is provided in the base station 100 _i , a predetermined process is performed for movement. When the reception system is provided in the telephone desk 103 _i , it is demodulated by the demodulator 15.

When the received signal from the receiver 11 is a multiplex control monitoring signal CW or a control monitoring multiplex signal, the multiplex control monitoring signal CW is extracted by the HPF 12 and supplied to the BPFs 14 _{1 to} 14 ₄ for multiplex control. A control monitoring signal that is time-division multiplexed with the monitoring signal CW is extracted from _one of the BPFs 14 _{1 to} 14 ₄ and output.

Here, the BPFs 14 ₁ , 14 ₂ , 14 ₃ , and 14 _{4 respectively} extract and extract the control monitoring signals CW ₁ , CW ₂ , CW ₃ , and CW ₄ , and the BPF 14 ₁ has a center frequency of the passband. f ₁ (2,900 Hz in the above example), and the control monitoring signal CW ₁ is separated and extracted, and the BPF 14 ₂ has a passband center frequency of f ₂ (3,000 Hz in the above example). ), And the control monitoring signal CW ₂ is separated and extracted. The BPF 14 ₃ has a passband center frequency f ₃ (3,100 Hz in the above example), and the control monitoring signal CW ₃ The BPF 14 ₄ separates and extracts the control monitoring signal CW ₄ with a center frequency of the pass band f ₄ (3,200 Hz in the above example).

  FIG. 4 is a diagram showing the separation and extraction operation of the control monitoring signal of the receiving system when the transmission signal from the transmitting system shown in FIG. 1A is the control monitoring multiplexed signal shown in FIG. The same reference numerals are assigned and duplicate descriptions are omitted.

In the figure, in the period t (1) of the control monitoring multiplexed signal received by the receiver 11 and separated and extracted by the HPF 12, the control monitoring signal CW ₁ is separated and extracted from the control monitoring multiplexed signal by the BPF 14 ₁ . At t (2), the control monitoring signal CW ₂ is separated and extracted from the control monitoring multiplexed signal by the BPF 14 ₂ . In the periods t (3) and t (4), since the control monitoring signal is not received, the control monitoring signal is not extracted from the BPFs 14 ₃ and 14 ₄ , but when the control monitoring signal CW ₃ is received in the period t (3). The control monitoring signal CW ₃ is separated and extracted from the BPF 14 _3, and when the control monitoring signal CW ₄ is received in the period t (4), the control monitoring signal CW ₄ is separated and extracted from the BPF 14 ₄ .

The control monitoring signals CW ₁ , CW ₂ , CW ₃ , and CW ₄ detected by the BPFs 14 ₁ , 14 ₂ , 14 ₃ , and 14 ₄ are supplied to a control monitoring signal period detector (not shown), and the signal period of each control monitoring signal is shown. Is detected.

FIG. 5 is a block diagram showing a specific example of such a control monitoring signal period detection device, in which 16 is a signal detection unit, 17 is a signal period detection unit, 18 ₁ and 18 ₂ are timers, and 19 is an AND gate. . Here, the signal CW _i any control and monitoring signals.

  FIG. 6 is a waveform diagram showing signals at various parts in FIG. 5, and the signals corresponding to those in FIG.

5 and 6, the control monitoring signal CW _i detected by the BPF 14 _i (any _{one of} the BPFs 14 ₁ , 14 ₂ , 14 ₃ , and 14 ₄ ) in FIG. 1B is supplied to the signal detection unit 16. full-wave rectification, smoothed by the signal processing such as level comparison, detects the signal period of the control monitor signal CW _i for each period t (i), the detection signal S _D representing in the signal period "L" (low level) Is output. This detection signal S _D is supplied to the signal period detection unit 17. Signal period detector 17, for example, a set-reset type flip-flop, by being set at the falling edge of the detection signal S _D (starting end of the detection signal S _D), the output of the Q terminal becomes "L" next, is reset by a reset pulse P _R from aND locate 19, the output of the Q terminal becomes "H" (high level).

Therefore, the detection signal S _D for each 4 times the period T ₀ of the period T _CK of the clock CK from the signal detection unit 16 in FIG. 2 (a) is sequentially outputted, as described later, in this case, and reset pulse P _R is not generated from the gate 19, the signal period detection unit 17 is set for each falling edge of the detection signal S _D, the output of the Q terminal of the signal period detection unit 17 held at a "L" Is done.

The detection signal _SD output from the signal detector 16 is also supplied to the timers 18 ₁ and 18 ₂ . The timers 18 ₁ and 18 ₂ are reset at each falling edge of the detection signal _SD , and time measurement is performed from the timing. The timer 18 ₁ and the timer 18 ₂ alternately perform this time measurement operation. That is, now, when the first detection signal S _D is output from the signal detection unit 16, this detection signal S _D is supplied to _{one of} the timers 18 ₁ and 18 ₂ , for example, the timer 18 ₁ , and its rise. the falling edge, the timer 18 ₁ starts time measurement is reset. Until this time, the detection signal _SD is not supplied to the timer 18 ₂ , but when the timer 18 ₁ is reset and time measurement is started, the detection signal output next from the signal detector 16. S _D can be supplied to the timer 18 ₂ , and the timer 18 ₁ is not supplied with the detection signal S _D. In this way, the detection signal S _D output from the signal detection unit 16 is alternately supplied to the timer 18 _1, 18 _2, thereby, the timer 18 _1, 18 ₂ performs the time measuring operation alternately.

Here, one cycle of control and monitoring signals CW _i T ₀ (provided that when the control monitoring signals CW ₁ ~CW ₄ shown in FIG. _{2, T 0 = 4 · T} CK) When timer 18 _1, 18 ₂ From the start of time measurement operation by reset,
T ₀ ≦ T <T ₀ + T _CK
When a time that satisfies the conditions elapses, a timing pulse _PT is output. This timing pulse P _T is within the signal period of the detection signal _SD output next from the signal detector 16.

The timing pulse _PT output from the timers 18 ₁ and 18 ₂ is supplied to the AND gate 19 together with the detection signal _SD output from the signal detector 16. The AND gate 19, whether the detection signal S _D from the signal detecting section 16 is output, therefore, be for the control monitor signal CW _i is detected whether it is received, the timing pulse P when the detection signal S _D from the signal detector 16 "L" is supplied _{when T} is supplied to the aND gate 19, there is a detection signal S _D, i.e., as a control monitor signal CW _i is received When the timing pulse P _T is not output from the AND gate 19, but the “L” detection signal _SD is not supplied from the signal detector 16 when the timing pulse P _T is supplied to the AND gate 19, the detection signal S _D is no, i.e., as a control monitor signal CW _i is not received, the aND gate 19 the timing pulse P _T, as a reset pulse P _R, and outputs. This reset pulse P _R, the signal period detection unit 17 is reset, the output of the Q terminal becomes "H".

Thus, when the control monitor signal CW _i starts to be received, by the falling edge of the start of the detection signal S _D output from the signal detection unit 16 in the first, the Q terminal of the signal period detection unit 17 is set output becomes "L" of, then, when the control monitor signal CW _i is not received, the reset pulse P _R from the aND gate 19, the output of the Q terminal signal period detecting unit 17 is reset to "H" It becomes. Thus, from the Q terminal of the signal period detection unit 17, so that the control monitoring period signal S _CW of "L" represents the reception period of the control monitor signal CW _i is obtained.

In FIG. 6, the control monitoring period signal S _CW when the detection signal SD is output twice from the signal detection unit 16 is indicated by a solid line, and when the detection signal S _D is output once from the signal detection unit 16 The control monitoring period signal S _CW is indicated by a broken line.

  As described above, in this reception system, an addition control monitoring signal in which the control monitoring signal from the transmission system shown in FIG. 1A is time-division multiplexed, or a control monitoring multiplexed signal of this addition control monitoring signal and the audio signal. Is received, it is possible to separate and extract the respective control monitoring signals, and to separate and extract the control monitoring signals from the receiving system in the conventional frequency division multiplexing system shown in FIG. It is only necessary to add a simple circuit such as a BPF, the circuit configuration is not complicated, and the cost can be reduced.

It is a block block diagram which shows the transmission system in one Embodiment of the transmission system of the control monitoring signal in the radio | wireless communications system by this invention. It is a figure which shows the receiving system with respect to the transmission system shown to Fig.1 (a). It is a wave form diagram which shows the signal of each part in Fig.1 (a). It is a schematic spectrum figure which shows the control monitoring multiplex signal for every period of the addition control monitoring signal and audio | voice signal transmitted from the transmission system shown to Fig.1 (a). It is a figure which shows the isolation | separation extraction operation | movement of the control monitoring signal of a receiving system when the transmission signal from the transmission system shown to Fig.1 (a) is the control monitoring multiplexed signal shown in FIG. It is a block block diagram which shows one specific example of the control monitoring signal period detection apparatus in the receiving system shown in FIG.1 (b). It is a wave form diagram which shows the signal of each part in FIG. 1 is a system configuration diagram showing a conventional example of a wireless communication system. It is a figure which shows an example of the frequency division multiplexing transmission system performed between the telephone desk in FIG. 7, and a base station.

Explanation of symbols

1 clock generator 2 gate signal generator 3 ₁ , 3 ₂ , 3 ₃ , 3 ₄ oscillator 4 ₁ , 4 ₂ , 4 ₃ , 4 ₄ gate circuit 5 ₁ , 5 ₂ , 5 ₃ , 5 ₄ transmission permission gate circuit 6 Adder 7 Modulator 8 LPF
9 Adder 10 Transmitter 11 Receiver 12 HPF
13 LPF
14 ₁ , 14 ₂ , 14 ₃ , 14 ₄ BPF
15 demodulator 16 signal detection unit 17 signal period detection unit 18 _1, 18 ₂ timer 19 AND gates 100 _1, 100 _2, ......, 100 _n base station 101 _1, 101 _2, ......, 101 _n repeater 102 relay connection Devices 103 ₁ , 103 ₂ ,..., 103 _n telephone table

Claims (2)

Includes a base station that performs radio communication with a mobile, performs a monitoring and control of the base station, and a call table for performing communication of voice signals between the mobile via the base station, the base A wireless communication system for communicating a plurality of control monitoring signals for controlling or monitoring the base station between a station and the telephone table,
The plurality of control monitoring signals are a plurality of control signals respectively supplied from the telephone desk to the base station or a plurality of monitoring signals supplied from the base station to the telephone desk,
The plurality of control signals or the plurality of monitoring signals are different in frequency from each other in a frequency band different from the frequency band of the audio signal, and periodically multiplexed and transmitted at different timings,
A wireless communication system, wherein communication is performed between the base station and the telephone desk. The wireless communication system according to claim 1, wherein
The audio signal is an audio signal in which a high frequency side of an audio band is limited,
A radio communication system, wherein a frequency band different from the frequency band of the audio signal is a high frequency band of the audio band.

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