JPH03195132A - Method and equipment for receiving radio selective call - Google Patents

Abstract

PURPOSE:To suppress the degradation of sensitivity caused by a disturbing signal by detecting an interference wave component caused by the disturbing signal included in a received call signal and executing control based on the result of this detection so that the interference wave component can be minimized. CONSTITUTION:As an interference wave removing means to detect the interference wave component caused by the disturbing signal included in the received call signal and to execute control so that the interference wave component can be made minimum, an interference wave detection part 7 is provided to detect the interference wave component caused by the disturbing signal included in the received call signal. An interference wave control part 9 is provided to sent out a control signal 9a based on this detected result, and a band erasing filter 4 is provided to vary an erasing frequency band according to the control signal 9a and to erase the interference component. Thus, the interference component caused by the disturbing signal is erased and the sensitivity degradation of this equipment can be suppressed at a minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is utilized in a radio selective call receiving device, and particularly relates to a direct conversion radio selective call receiving method and device that demodulates FM directly from line frequency.

〔overview〕

The present invention provides a wireless selective call reception method for selectively receiving a paging signal addressed to a receiving device that is transmitted wirelessly, in which an interference wave component due to an interfering signal contained in the received paging signal is detected; By controlling the interference wave component to the minimum based on the results, it is possible to suppress deterioration in sensitivity due to interfering signals.

[Conventional technology]

Conventional wireless selective call receiving device (hereinafter referred to as receiving device).

) is configured to degrade the S/N and sensitivity when the line receives an interference signal from an external source.

Particularly, in recent years, as one of the miniaturization technologies, a direct conversion system that demodulates FM directly from the line frequency has been sold. In this type of system, since the local oscillation circuit is approximately at the line frequency, when this type of receiving device approaches another receiving device, the sensitivity of the other receiving device will deteriorate. In other words,
A type of transmitter that uses very little power is starting to appear.

FIG. 13 is a block diagram showing an example of a receiving device using such a direct conversion method. A radio signal input from an antenna 1 is amplified by a radio frequency amplifier (RFA) 2, selected by a band pass filter (BPF) 3, and then sent to a direct demodulator (DEM).
) is in 5. Here, it is mixed with a local oscillation signal from the local oscillator (OSC) 8 that matches the line frequency, and
Demodulation of M is performed and decoded by a decoder (DEC) 6.

[Problem that the invention seeks to solve]

The conventional receiving device mentioned above is vulnerable to external signals on the same line, and especially when a direct conversion type receiving device comes nearby, the reception sensitivity deteriorates and it becomes unable to perform its original function. There are drawbacks.

In addition, in this type of direct conversion type receiving device, the carrier radiated from the local oscillator of the own device does not degrade the sensitivity of the own device, and only interferes with the outside, so the receiver radiates from the local oscillator of the own device. Although the impact depends on the extent to which the manufacturer takes measures such as shielding to prevent leakage of the oscillation circuit, there are limits to the measures that can be taken on the side that generates the interfering signal.

Note that even with the conventional double or single super system, there is a possibility that the local oscillation circuit overlaps with some line, so there is still a possibility that the sensitivity will deteriorate. This is a serious problem, especially in urban areas where there are many mobile communication devices.

SUMMARY OF THE INVENTION An object of the present invention is to provide a radio selective call reception method and apparatus that can suppress deterioration of sensitivity due to interfering signals by eliminating the above-mentioned drawbacks.

[Means for solving problems]

The radio selective call reception method of the present invention is a radio selective call reception method in which a radio selective call reception method selects and receives a paging signal addressed to a receiving device that is transmitted by radio. is detected, and control is performed so that the interference wave component is minimized based on the detection result.

The radio selective call receiving device of the present invention includes selective receiving means for selectively receiving a paging signal addressed to the own receiving device that is transmitted by radio. The present invention is characterized by comprising an interference wave removing means that detects an interference wave component due to an interference signal and controls the interference wave component to be the lowest based on the detection result.

Further, in the radio selective paging receiving device of the present invention, the interference wave removing means includes an interference wave detection section that detects an interference wave component due to an interfering signal in a received paging signal, and a detection result in the interference wave detection section. The interference wave control section may include an interference wave control section that sends out a control signal based on the interference wave control section, and a band elimination filter that makes the cancellation frequency band variable in accordance with the control signal from the interference wave control section and cancels the interference wave component.

Further, in the radio selective calling receiving device of the present invention, the interference wave detection unit detects an automatic gain control amplifier that receives the output of a high frequency amplifier or an intermediate frequency amplifier of the receiving device, and an output of the automatic gain control amplifier. It is preferable to include an interference wave detection unit that outputs an interference wave output.

Further, in the radio selective call receiving device of the present invention, it is preferable that the band-elimination filter is a digitally controlled band-elimination filter.

[Effect]

The interference wave component due to the interference signal is detected by the interference wave detection section, and based on the detection result, the interference wave control section outputs a control signal for controlling the cancellation band of the band cancellation filter. Then, the band elimination filter eliminates the human signal in a frequency band with interference wave components according to this control signal.

Therefore, the interference wave component due to the interference signal is eliminated, and it becomes possible to suppress deterioration of the sensitivity of the device to the minimum.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of an embodiment of the receiving device of the present invention, FIG. 2 is a block diagram showing an example of the interference wave detection section, and FIG. 3 is an example of the band elimination filter. FIG.

According to FIG. 1, the present embodiment includes an antenna 1, a radio frequency amplification unit (RFA) 2, a band pass filter (BPF) 3, In a receiving device equipped with a direct demodulator (DEM) 5, a decoder (DEC) 6, and a local oscillator (O3C) 8, the present invention is characterized by the following: as an interference wave removal means that detects an interference wave component caused by a signal and controls the interference wave component to be the lowest based on the detection result;
An interference wave detection section (DBS) 7 that detects an interference wave component due to an interference signal in a received calling signal, and an interference wave control section (DBS) that sends out a control signal 9a based on the detection result of the interference wave detection section 7. COT) 9 and a band-elimination filter (BEF) 4 that makes the cancellation frequency band variable in accordance with a control signal 9a from the interference wave controller 9 and cancels the interference wave component.

According to FIG. 2, the interference wave detection unit 7 includes an automatic gain control amplifier (AGCAMP) 11 that inputs the output of a high frequency amplifier or an intermediate frequency amplifier of the receiving device to an input terminal lO, and an automatic gain control amplifier (AGCAMP) 11 that inputs the output of the high frequency amplifier or intermediate frequency amplifier of the receiving device to It includes an interference wave output detection section (DET) 12 that detects and outputs an interference wave output 13.

Note that here, the input terminal 10 of the interference wave detection section 7 is connected to the output of the band elimination filter 4, and together with the interference wave control section 9 constitutes a negative feedback circuit for interference components.

According to FIG. 3, the band elimination filter 4 includes a BEF amplifier (BEFAMP) 21 consisting of an operational amplifier whose input is connected to an input terminal 20 and whose output is connected to an output terminal 22, and a positive-phase input terminal of the operational amplifier. The coil connected to (
L) 23, a capacitor (C) 24 connected between the coil 23 and ground, and a control terminal 31.3 in parallel with the common connection point between the coil 23 and the capacitor 24, respectively.
Transfer gate (1) (TG,) 25, (2) (TG2) 26 connected between 2 and 33
and (3) (TG, ) 27 and capacitors (C,) 28, (C,
)29 and (C,)30. Note that a plurality of n circuits including this transfer gate are connected.

This band elimination filter 4 is digitally controlled and uses a series resonant circuit to drop the input signal.

Center frequency f of the bandstop filter. is given by, where C is the transfer gate (1)2
5, (2) 26, and (3) 27 are turned on. In the case of transfer game H1) 25, the signal component of this frequency is eliminated.

Note that as the band-elimination filter 4, not only this example but also a SAW filter array, an XTL filter array, etc. can be used.

Next, the operation of this embodiment will be explained with reference to FIGS. 4 to 12.

FIG. 4 is a flowchart showing the operation of the interference wave control section 9.

When the receiving device starts receiving operation (step S1), it is checked whether there is an interference wave detection output from the interference wave detector 7 (step S2), and if there is an interference wave detection output,
The control signal 9a is sent to vary the band-stop filter 4 (
Step S3). It is checked whether the interference wave detection power has reached the lowest level as a result of the variation (step S4), and if it has reached the lowest level, the cancellation band of the band elimination filter 4 is fixed (step 35). If there is no interference wave detection output in step S2, the receiving operation continues as it is.

FIG. 5 shows sideband waves 41 of an FM-modulated calling signal. If an interfering signal, for example an interfering signal 42, enters within the band, such as when a direct conversion receiver comes nearby, the result will be as shown in FIG.

FIG. 7 shows a state in which the interference signal 42 seen in FIG. 6 is suppressed by the band-elimination filter (BEF) 4 to produce an interference signal 43. Although the interference signal 43 cannot be completely eliminated, it is considerably reduced.

Next, an example of the characteristics of the band-stop filter 4 is shown in FIG. In FIG. 8, 44, 45 and 46 indicate frequency characteristics, and represent passing characteristics. Characteristic 44 is the center frequency f.

Characteristic 45 is for low frequency operation, and characteristic 46 is for high frequency operation. That is, the variable range of this band-stop filter 4 is from frequency fL to fH.

FIG. 9 is an example of a waveform in which interference is caused by adding interference to the FM signal shown on the time axis. Here, f.

is the desired wave component to be received, and f is the beat component generated by interference.

FIG. 10 is a half-wave waveform obtained by rectifying the interference waveform shown in FIG. 9. FIG. 11 shows an interference wave component 48 obtained by smoothing the rectified waveform obtained in FIG. 10.

FIG. 12 shows the state of the interference wave output obtained by further integrating the interference wave component 48 obtained in FIG. 11 into a DC component. In FIG. 12, 50 indicates that the interference wave output 49 has decreased as the interference component is suppressed by the operation of the band elimination filter 4. The reason why the output changes stepwise is that a digitally controlled band-stop filter is used as the band-stop filter 4 in this embodiment.

Next, this interference wave output is applied to the interference wave control section 9, the strength of the interference is detected, and a control signal 9a is sent out accordingly.

〔Effect of the invention〕

As explained above, the present invention automatically detects deterioration in sensitivity due to external interference signals on a line or intermediate frequency,
This has the effect of eliminating the interfered portion of the band using a band elimination filter, thereby minimizing sensitivity deterioration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention. FIG. 2 is a block diagram showing an example of the interference detection section. FIG. 3 is a block diagram showing an example of the band-stop filter. FIG. 4 is a flowchart showing the operation of the interference control section. FIG. 5 is a diagram showing FM-modulated sideband waves. FIG. 6 is a diagram showing an interference signal. FIG. 7 is a diagram showing a suppressed interference signal. FIG. 8 is a diagram showing frequency characteristics of a band-elimination filter. FIG. 9 is a diagram showing an interference state of a calling signal. FIG. 10 is a diagram showing a half-wave waveform of an interference waveform. FIG. 11 is a diagram showing detected interference wave components. FIG. 12 is a diagram showing the output of interference wave components. FIG. 13 is a block diagram showing the main parts of a conventional example. l... antenna, 2... radio frequency amplification section (RFA),
3...Band pass filter (BPF), 4...Band elimination filter (BEF), 5...Direct demodulation section (DE
M), 6... Decoder (DEC), 7... Interference wave detection section (DES), 8... Local oscillation section (O3C),
9... Interference wave control unit (COT), 9a... Control signal, 1O120... Input terminal, 11... AGC amplifier (AGCAMP), 12... Interference wave output detection unit (
DET), 13... Interference output, 21... BEF amplifier (BEFAMP), 22... Output terminal, 23
...Coil, 24.28.29.30...Capacitor, 25.26.27...Transfer gate (1)
, (2) , (3) (TCz, TG2, TG3
), 31.32.33... Control terminal, 41... Sideband wave, 42.43... Interfering signal, 44.45.46.
... Frequency characteristics, 47... Half wave waveform, 48... Interference wave component, 49.50... Interference wave output.

Claims (1)

[Claims] 1. In a wireless selective call reception method for selectively receiving a paging signal addressed to a receiving device transmitted wirelessly, detecting an interference wave component due to an interfering signal contained in the received paging signal. A radio selective call reception method characterized in that the interference wave component is controlled to be at a minimum based on the detection result. 2. In a wireless selective paging receiving device equipped with a selective receiving means for selectively receiving a paging signal destined for the own receiving device transmitted wirelessly, detecting an interference wave component due to an interfering signal contained in the received paging signal. A radio selective call receiving device characterized in that it comprises an interference wave removing means for controlling the interference wave component to be the lowest based on the detection result. 3. The interference wave removing means includes an interference wave detection unit that detects an interference wave component due to an interference signal in the received calling signal, and an interference wave control unit that sends out a control signal based on the detection result of the interference wave detection unit. 2. The radio selective receiving apparatus according to claim 1, further comprising a band elimination filter that makes the cancellation frequency band variable in accordance with a control signal from the interference wave control section and cancels the interference wave component. 4. The interference wave detection unit includes an automatic gain control amplifier that inputs the output of the high frequency amplifier or intermediate frequency amplifier of the receiving device, and an interference wave detection unit that detects the output of the automatic gain control amplifier and outputs an interference wave output. 4. The wireless selective call receiving apparatus according to claim 3, further comprising: a wireless selective call receiving apparatus; 5. The radio selective call receiving apparatus according to claim 3, wherein the band-elimination filter is a digitally controlled band-elimination filter.