JPH0993171A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the receiver to cope flexibly with fluctuation in the transmission characteristic while simplifying the configuration of the hardware in the receiver of the diversity system. SOLUTION: The receiver is made up of a branch selection means 11 receiving a reception wave incoming to plural branches and selecting the wave in a recyclic way at an interval of a fraction of an integer of a symbol period, a demodulation means 12 applying demodulation processing to the reception wave at a band wider than the occupied band width, a level measurement means 13 measuring the level of a selected reception wave, an A/D converter means 14 applying A/D conversion to the demodulation signal while separating the signal for each branch to obtain plural digital signals, a band limit means 15 applying band limit processing in parallel with the digital signal so as to limit the reception band to be less than the occupied band width, and a signal judgement means 16 selecting a digital signal with a highest level measured by the level measurement means 13 among the digital signals subjected to band limit processing in the unit of symbols to discriminate a signal point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver to which a diversity system is applied in a wireless transmission system.

[0002]

2. Description of the Related Art In a radio transmission line formed between a base station and a mobile station of a mobile communication system, transmission characteristics are such that a loss occurs due to topography or a feature located on the radio transmission line, or a reflection propagation line is generated. Formed and, in addition, changes significantly as the mobile station moves.

Therefore, a mobile station apparatus is generally applied with a diversity reception system adapted to such a transmission system of a wireless transmission line and a channel setting control system via the wireless transmission line. FIG. 12 is a diagram (1) showing a configuration example of a conventional receiving device. In the figure, the feeding ends of the antennas 161 ₁ and 161 ₂ that individually configure two branches are connected to the corresponding inputs of the antenna switch 162, respectively.
The output of the switch is connected to the input of the demodulator 164 and one input of the level detection unit 165 via the frequency conversion unit 163. The control input of the antenna switch 162 and the other input of the level detection unit 165 are connected to the corresponding outputs of the antenna switching control unit 166, and the demodulator 164 and the level detection unit 165 have the corresponding outputs, respectively. The received electric field strength RSSI is obtained.

In the receiver having such a configuration, the antenna
The switching control unit 166 uses a frame adapted to the TDMA system.
Time slot R to be received by the own station based on the frame configuration
Of the timing (Fig. 13) and the time slot
2 adjacent to each other in advance by a predetermined time
During the period (Fig. 13) of the antenna 161 ₁ 
Feeding end and antenna 161₂ Connect the power supply end of
Touch 16₂ Connected to the input of the frequency conversion unit 163 via
You.

The frequency conversion unit 163, among the reception waves thus respectively supplied from the antennas 161 ₁ and 161 ₂ , the reception wave of the same frequency as the above-mentioned time slot R is an intermediate frequency of a prescribed frequency (for example, 455 kHz). Convert to frequency signal. The demodulator 164 generates a demodulated signal DAT by demodulating such an intermediate frequency signal, and the level detection unit 165 concurrently operates the level RS of the intermediate frequency signal.
Measure SI.

Further, a processor (not shown) compares the levels thus measured in association with the above-mentioned two periods, and the antenna switch 162 causes the frequency conversion unit to operate in one of the periods with the higher level. 1
63 antenna connected to the input of the (antenna 161 _1, 1
Either one of 61 ₂ ) feeding end is selected during the time slot R, and is connected to the input of the frequency conversion unit 163 again.

That is, in such a conventional example, since the reception processing based on the antenna switching diversity system via the two branches is surely performed via the single frequency conversion unit 163 and the demodulator 164, it is particularly portable. It is often used in terminal devices such as mobile station devices, which are required to be light in weight in addition to being inexpensive and compact. FIG. 14 is a diagram (2) showing a configuration example of a conventional receiving device.

In the figure, parts having the same functions and configurations as those shown in FIG. 12 are designated by the same reference numerals, and the description thereof will be omitted here. In the conventional example shown in FIG. 14, the feeding ends of the antennas 161 ₁ and 161 ₂ are connected to the inputs of the frequency converters 171 ₁ and 171 ₂ , respectively. The output of the frequency converter 171 ₁ is connected to the input of the demodulator 172 ₁ and _one input of the level detector 173, and the output of the frequency converter 171 _{2 is} the input of the demodulator 172 ₂ and the other of the level detector 173. Connected to the input. Demodulator 172
The outputs of ₁ and 172 _{2 and} the outputs corresponding to the respective inputs of the level detection unit 173 are respectively connected to the corresponding inputs of the selection unit 174, and the demodulated signal DAT is connected to the first output and the second output of the selection unit. And the medical examination field strength RSSI are obtained.

In the conventional example having such a configuration, the antenna 1
The received waves captured by 61 ₁ and 161 ₂ are demodulated in parallel by the frequency conversion unit 171 ₁ and the demodulator 172 ₁ and the frequency conversion unit 171 ₂ and the demodulator 172 ₂ , respectively. The level detection unit 173 measures the received electric field strengths of these received waves at the output ends of the frequency conversion units 171 ₁ and 171 ₂ . The selection unit 174 compares the received electric field strengths measured in this way, and the demodulators 172 ₁ , 1
Of the demodulated signals obtained in parallel from 72 ₂ , the one having the highest received electric field strength is selected and output.

That is, in the receiving apparatus to which the post-detection diversity method is applied, demodulation of the received wave obtained through each branch is performed in parallel.
It is possible to obtain a demodulated signal of a branch having a large received electric field strength by switching in symbol units under the applied modulation method, and a high transmission quality is secured even when the fading frequency is high.

[0011]

However, among the above-mentioned conventional examples to which the antenna switching diversity system is applied, when the fading frequency is high, each measured before the reception time slot R. It was difficult to keep the transmission characteristics high because the received electric field strengths of the branches were significantly different during the receiving time slot.

Further, in the conventional example to which the diversity system after detection is applied, since the two frequency converters and the demodulator are mounted, the scale of the hardware becomes large, and compared with the receiving device of the antenna switching diversity system. Therefore, it cannot be applied to a terminal device such as a portable mobile station device, which is required to be inexpensive, downsized, and lightweight.

It is an object of the present invention to provide a receiving apparatus which can flexibly adapt to variations in transmission characteristics of a wireless transmission line while avoiding an increase in scale and complexity of configuration related to hardware.

[0014]

[Means for Solving the Problems] FIG.
It is a principle block diagram of the invention as described in 10.

According to the first aspect of the present invention, a plurality of received waves that individually arrive in a plurality of branches are taken in, and these received waves are sequentially recycled at intervals of an integer fraction of the symbol period along the time axis. Branch selection means 11 to select
A demodulation means 12 for demodulating the received wave selected by the branch selection means 11 in a band wider than the occupied bandwidth of the received wave to obtain a demodulated signal; and a received wave selected by the branch selection means 11. A / D conversion is performed while separating the demodulation signal obtained by the level measurement means 13 for measuring the level and the demodulation means 12 at the timing of the selection performed by the branch selection means 11, and a plurality of branches individually corresponding to the plurality of branches. Obtaining a digital signal A
A / D converting means 14 and a band limiting means for subjecting a plurality of digital signals obtained by the A / D converting means 14 to a band limiting process in parallel and setting a reception band of the plurality of received waves to be equal to or less than an occupied bandwidth. 15 and the digital signal subjected to the band limiting process by the band limiting unit 15, the digital signal having the maximum level measured by the level measuring unit 13 is selected for each symbol to determine the signal point in the signal space. And a signal determining means 16 for performing.

FIG. 2 is a block diagram showing the principle of the invention according to claims 2, 4 to 10. According to the second aspect of the present invention, a plurality of received waves that individually arrive in a plurality of branches are taken in, and these received waves are sequentially and cyclically selected at intervals of an integral fraction of the symbol period along the time axis. The branch selecting means 11 and the demodulating means 12 for performing demodulation processing on the received wave selected by the branch selecting means 11 in a band wider than the occupied bandwidth of the received wave to obtain a demodulated signal.
A level measuring means 13 for measuring the level of the received wave selected by the branch selecting means 11, and a demodulating means 12
A / D conversion means 14 for obtaining a plurality of digital signals individually corresponding to a plurality of branches while separating the demodulated signal obtained by A / D conversion at the timing of selection performed by the branch selection means 11. / D conversion means 14
Band limiting means 15 for performing band limiting processing in parallel on the plurality of digital signals obtained by the above, and setting the receiving bands of the plurality of received waves to be equal to or less than the occupied bandwidth, and the band limiting means 15.
And a synthesizing unit 21 for deciding a signal point in the signal space by synthesizing the digital signals band-limited by the above in symbol units.

According to a third aspect of the present invention, in the receiving apparatus according to the first aspect, the signal determining means 16 indicates the distance in the signal space between the digital signal whose signal point is determined and the signal point. The branch selecting means 11 includes a means for determining, and the branch selecting means 11 determines the magnitude relationship between the distance obtained by the signal determining means 16 or the average value of the distance and a preset threshold value, and selects when the former falls below the latter. Is postponed and, on the contrary, resumes its selection when it is exceeded.

According to a fourth aspect of the present invention, in the receiving apparatus according to the second aspect, the synthesizing means 21 includes a signal between a vector sum of a plurality of digital signals whose signal points are determined and the signal points. The branch selecting means 11 includes a means for obtaining a distance in space, and the branch selecting means 11 determines a magnitude relationship between the distance obtained by the combining means 21 or an average value of the distance and a preset threshold value, and the former falls below the latter. It is characterized in that it comprises means for sometimes deferring the selection and for resuming the selection when it is exceeded on the contrary.

According to a fifth aspect of the present invention, in the receiving device according to any one of the first to fourth aspects, a radio channel setting control method applied to a radio transmission line in which a plurality of branches are arranged. On the basis of the procedure of 1., the branch selecting means 11 is provided with the state identifying means 31 for identifying the state in which the transmission quality of the received waves arriving at these branches is high or the degree of deterioration of the transmission quality is acceptable. ,
It is characterized in that it includes means for suspending or resuming selection depending on whether or not any one of the states is identified by the state identifying means 31.

According to a sixth aspect of the present invention, in the receiving device according to any one of the first to fourth aspects, a remaining capacity measuring means 41 for measuring a remaining capacity of a battery for supplying driving power is provided. The branch selection means 11 is characterized in that it includes means for comparing the remaining capacity measured by the remaining capacity measuring means 41 with a threshold value given in advance and suspending the selection when the former falls below the latter. .

According to a seventh aspect of the invention, in the receiving device according to any one of the first to fourth aspects, the fluctuation range and cycle of the level measured by the level measuring means 13 are monitored, Fading monitoring means 51 for judging whether or not the fluctuation range and the cycle are individually below a predetermined threshold value is provided, and the branch selecting means 11 is responsive to the truth or false of the judgment result made by the fading monitoring means 51. And includes means for suspending or resuming selection, respectively.

The invention according to claim 8 is the receiving apparatus according to any one of claims 1 to 7, wherein the plurality of digital signals band-limited by the band limiting means 15 are signaled. The demodulation means 12 is provided with a monitoring means 61 for obtaining the amplitude in space, and the demodulation means 12 has a monitoring means 61
Gain is increased / decreased with the amplitude obtained by
It is characterized by including means for compressing the deviation of the amplitude.

According to a ninth aspect of the present invention, in the receiving apparatus according to the first aspect, the monitoring means for individually obtaining the amplitudes in the signal space for the plurality of digital signals band-limited by the band limiting means 15. 71 _{1 to} 71 _N
And selecting means 72 for selecting the amplitude corresponding to the digital signal selected by the signal judging means 16 among the amplitudes obtained by the monitoring means 71 _{1 to} 71 _{N. The} demodulating means 12 includes the selecting means 72. It is characterized in that it includes means for increasing / decreasing the gain by using the amplitude selected by as a control amount and compressing the deviation of the amplitude.

The invention described in claim 10 is the receiving apparatus according to any one of claims 1 to 7, wherein the demodulating means 12, the A / D converting means 14 and the band limiting means 1 are provided.
Reference numeral 5 is provided with monitoring means 81 _{1 to} 81 _N that are individually redundant for a plurality of branches and individually obtain the amplitudes in the signal space of a plurality of digital signals that have been band-limited by the band limiting means 15. The demodulating means 12 is characterized in that it includes means for increasing or decreasing the gain in parallel with the amplitude individually obtained by the monitoring means 81 _{1 to} 81 _N as a control amount and compressing the deviation of these amplitudes.

In the receiving apparatus according to the first aspect of the present invention, the branch selecting means 11 recycles the received waves individually arriving at a plurality of branches at intervals of an integer fraction of the symbol period along the time axis. Then, the demodulating means 12 performs demodulation processing on the received wave selected in this manner while ensuring a band wider than the occupied bandwidth of the received wave. A / D
The converting means 14 obtains a plurality of digital signals by performing A / D conversion in parallel while separating the demodulated signal generated by the demodulating process for each branch at the timing of the selection described above. The band limiting means 15 performs band limiting processing in the digital area in parallel with these digital signals, thereby setting the reception band of the received wave arriving at each branch to the above-mentioned occupied bandwidth or less.

On the other hand, the level measuring means 13 measures the level of the received wave selected by the branch selecting means 11 as described above, and the signal judging means 16 detects the digital signal band-limited by the band limiting means 15. Among them, the one having the highest level measured in this way is selected to determine the signal point in the signal space. That is,
The demodulation means 12 does not perform band limiting processing for determining the reception band, and is shared by the time division multiplexing method in synchronization with the selection made by the branch selection means 11 for a plurality of branches, and further, the A / D conversion means 14 The sampling cycle of can be set short enough to satisfy the sampling theorem under the interval or cycle on the time axis at which the above selection is performed, so that the band limiting means 15 performs band limiting processing of these branches in parallel in the baseband region. Can be done reliably.

Therefore, under the common use of the demodulation means 12, reception processing of a plurality of branches is performed in parallel while suppressing an increase in hardware scale and power consumption, and fading faster than in the antenna switching diversity system. It is possible to respond flexibly. The receiving apparatus according to the invention described in claim 2 is different from the receiving apparatus according to claim 1 in that a synthesizing means 21 is provided in place of the signal determining means 16 described above. However, such a synthesis means 2
1, the band limiting means 15 synthesizes the band-limited digital signals in symbol units, then determines the signal point in the signal space, and the branch selecting means 11 to the band limiting means 15 arranged in the preceding stage have the following configurations. This is the same as the receiving device according to claim 1.

Therefore, in the receiving device according to the present invention, the receiving processing of a plurality of branches is performed in parallel while suppressing an increase in the scale of hardware and power consumption, as in the invention described in claim 1. Compared to the antenna switching diversity method, it becomes possible to flexibly cope with high-speed fading.

In the receiving apparatus according to the third aspect of the invention, the signal judging means 16 finds the distance in the signal space between the digital signal whose signal point is judged and the signal point, and the branch selecting means 11 is The magnitude relationship between the distance thus obtained or the average value of the distance and the preset threshold value is discriminated, and when the former is less than the latter, the selection is postponed, and when the latter is exceeded, the selection is restarted.

That is, since the demodulation means 12 is shared only in the state in which the received wave arriving at each branch is accompanied by fading or propagation loss that causes a significant deterioration of the transmission quality, in such a state The power consumed unnecessarily is reduced. In the receiving device according to the fourth aspect of the present invention, the synthesizing means 21 obtains the vector sum of a plurality of digital signals whose signal points are determined and the distance in the signal space between the signal points, and the branch selecting means 11 The magnitude relationship between the distance thus obtained or the average value of the distance and the preset threshold value is discriminated, and when the former is less than the latter, the selection is postponed, and when the latter is exceeded, the selection is restarted. .

That is, since the demodulation means 12 is shared only in a state in which the received wave arriving at each branch is accompanied by fading or propagation loss which causes a significant deterioration in transmission quality, the demodulating means 12 is used in such a state for its sharing. The power consumed unnecessarily is reduced. In the receiving device according to the fifth aspect of the invention, the state identifying means 31 arrives at these branches based on the procedure of the wireless channel setting control method applied to the wireless transmission path accessed through the plurality of branches. A state in which the transmission quality of the received wave is high or the degree of deterioration of the transmission quality is acceptable is identified. The branch selection means 11 postpones the selection if any one of these states is identified, and restarts the selection if no state is identified.

In other words, the demodulation means 12 is shared only in the state in which the received wave arriving at each branch is accompanied by fading or propagation loss which causes a significant deterioration of the transmission quality. The power consumed unnecessarily is reduced.

In the receiving apparatus according to the sixth aspect of the present invention, the remaining capacity measuring means 41 measures the remaining capacity of the battery supplying the driving power, and the branch selecting means 11 compares the remaining capacity thus measured with the remaining capacity. The selection is suspended when the former falls below the latter by comparing with a threshold value given in advance. That is, since the demodulation means 12 is shared only when the remaining capacity of the battery exceeds the above-mentioned threshold value, by setting the threshold value to a desired value in advance, the wireless transmission path is secured with priority over the transmission quality. .

In the receiving apparatus according to the seventh aspect of the invention, the fading monitoring means 51 is the level measuring means 13.
The fluctuation range and cycle of the level measured by are monitored, and it is determined whether or not the fluctuation range and cycle are below a predetermined threshold value. The branch selection means 11 postpones the selection if the result of the determination made in this way is true, and, on the contrary, restarts the selection if it is false.

That is, since the demodulation means 12 is shared only in the state in which the received wave arriving at each branch is accompanied by fading that causes a significant deterioration of the transmission quality, it is useless in such a state for the sharing. Power consumption is reduced. In the receiving device according to the present invention as defined in claim 8, the monitoring means 61 obtains the amplitudes in the signal space of the plurality of digital signals band-limited by the band limiting means 15, and the demodulating means 12 obtains in this way. The gain is increased or decreased by using the obtained amplitude as a control amount to compress the deviation of the amplitude.

That is, since the transmission loss and the variation of the wireless transmission line individually formed with a plurality of branches as one end are reduced, the transmission quality is higher than that of the receiving device according to any one of claims 1 to 7. Is increased. In the receiving apparatus according to the invention of claim 9, the monitoring means 71 ₁ -71 _N are determined individually amplitude in the signal space for a plurality of digital signals band limitation processing is performed by the band limiting means 15, selection means 72 Selects the amplitude corresponding to the branch selected by the signal determination means 16 from the amplitudes thus obtained. The demodulation means 12 is the selection means 7
The gain is increased or decreased with the amplitude selected by 2 as the control amount, and the deviation of the amplitude is compressed.

That is, the transmission loss of the wireless transmission line formed individually with a plurality of branches as one end and its fluctuation amount are reduced, and the control amount serving as a reference for the reduction is selected by the signal judging means 16 as a digital signal. Since it is given by the amplitude of the branch, the transmission quality is further improved as compared with the receiving device according to the eighth aspect. In the receiving device according to the tenth aspect of the present invention, the demodulating means 12, the A / D converting means 14, and the band limiting means 15 are made redundant corresponding to the plurality of branches individually, and the monitoring means 81 _{1 to} 81 _N are The amplitudes in the signal space are individually calculated for the plurality of digital signals that have been band-limited by the band limiting means. In this way, the demodulation means 12 increases / decreases the gain in parallel with each amplitude as a control amount, and compresses the deviation of these amplitudes.

That is, since the transmission loss and the fluctuation of the wireless transmission line formed individually with a plurality of branches as one end are reduced in parallel via separate systems separated for each branch, Deterioration of transmission quality due to transmission loss and fluctuation is highly accurately reduced.

[0039]

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

FIG. 3 is a diagram showing an embodiment corresponding to the invention described in claims 1 and 8. In the figure, components having the same functions and configurations as those shown in FIG. 12 are denoted by the same reference numerals, and description thereof is omitted here. The output of the antenna switch 162 is connected to the inputs of the demodulator 92 and the level detection unit 93 via the frequency conversion unit 91,
The output of the demodulator 92 is connected to the input of the A / D converter 94. The first output and the second output of the A / D converter 94 are respectively the root roll-off filter 9
5 _1, 95 is connection ₂ to the discriminator 96 corresponding inputs via a demodulated signal DAT is obtained at the output of the discriminator.
The reception field strength RSSI is obtained at the output of the level detection unit 93 as in the conventional example, and the reception field strength RSSI is given to the input of the antenna switching control unit 97. One output of the antenna switching control unit 97 is connected to the control input of the antenna switch 162 and the clock input of the A / D converter 94, and the other output is connected to the clock input of the discriminator 96.

Regarding the correspondence relationship between this embodiment and the block diagram shown in FIG. 1, the antenna switch 162 and the antenna switching control section 97 correspond to the branch selecting means 11, and the frequency conversion section 91 and the demodulator 92 demodulate. Means 1
2, the level detecting unit 93 corresponds to the level measuring unit 13, the A / D converter 94 corresponds to the A / D converting unit 14, and the root roll-off filters 95 ₁ and 95 ₂ correspond to the band limiting unit 15. However, the discriminator 96 uses the signal determination means 16
And a selector 98 and an AGC control unit 9 which will be described later.
Reference numeral 9 corresponds to the monitoring means 61.

The operation of this embodiment will be described below. The antenna switching control unit 97 uses the antenna 161 for the integer N.
_1, 161 ₂ to 4N times no symbol rate of the received wave arriving to generate a clock of a frequency of 16N times, gives the clock to the antenna switch 162 and the A / D converter 94.

The antenna switch 162 is the antenna 161.
_1, 161 ₂ reception wave arriving to select alternately in synchronism with such a clock, the frequency converting unit 91 converts the intermediate frequency signal to a predetermined capture a reception wave which is selected in this way . Here, for simplification, the frequency of the received wave and the frequency of the intermediate frequency signal are 800 MHz and 130 MHz, respectively, and the frequency conversion unit 91 also includes a local oscillator (not shown), which is not shown. , Its local oscillator generates 930 (6
70) A filter that extracts the component of the intermediate frequency signal of the sum difference between the frequency of the local oscillation signal of MHz and the frequency of the received wave and suppresses the components of the local oscillation signal and the received wave in the frequency domain (illustration Not included.) Is included.

The demodulator 92 demodulates such an intermediate frequency signal to generate a baseband signal. A /
The D converter 94 takes in the baseband signal, performs digital conversion on a symbol-by-symbol basis in synchronization with the clock given by the antenna switching control unit 97, and outputs the output of the conversion individually for the antennas 161 ₁ and 161 ₂ . Output to the route.

Root roll-off filters 95 ₁ and 95
₂ indicates that the pass band is approximately equal to the above-mentioned occupied band of the received wave and the amplitude distortion at the sampling timing performed by the A / D converter 94 is minimum with respect to the outputs of the conversions respectively given through these routes. It has the following transfer characteristics. The antenna switching control unit 97 uses the antenna 16
The electric field strengths of the received waves individually arriving at 1 ₁ and 161 ₂ are acquired through the level detection unit 93, and one of these antennas, which has a larger electric field strength, is symbol-unitized in synchronization with the clock described above. select.

The discriminator 96 discriminates the closest signal point in the signal space with respect to the signals obtained at the outputs of the root roll-off filters 95 ₁ and 95 ₂ , respectively, and among these signal points, the antenna switching is performed as described above. The control unit 97 sequentially selects the antennas corresponding to the selected antennas to generate and output the demodulated signal DAT. As described above, in the present embodiment, the root roll-off filters 95 ₁ and 95 ₂ perform band limitation in parallel in the digital domain to determine the reception band, and further, the frequency conversion unit 91, the demodulator 92, and the A / D converter.
The D converter 94 is shared by the received waves individually arriving at the antennas 161 ₁ and 161 ₂ . Therefore, the size of the hardware is reduced, and it is possible to adapt to a high fading frequency as in the conventional diversity system after detection. Further, regarding the A / D converter 94 and the root roll-off filters 95 ₁ and 95 ₂ that perform such processing in the digital area, a dedicated circuit is provided as an LSI.
Since the size can be reduced and the power consumption can be reduced, the present embodiment can be applied to a mobile type mobile station device.

In the above embodiment, the frequency of the clock given to the A / D converter 94 is set to 4N times to 16N times the symbol rate of the received wave. Any value may be set as long as the above-described digital processing is surely performed in parallel in the off filters 95 ₁ and 95 ₂ .

FIG. 4 is a diagram showing an embodiment corresponding to the invention described in claim 2. In FIG. In the figure, parts having the same functions and configurations as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted here. The difference between the present embodiment and the embodiment shown in FIG.
Instead of this, a combiner 131 is provided.

Regarding the correspondence relationship between this embodiment and the block diagram shown in FIG. 2, the antenna switch 162 and the antenna switching control unit 97 correspond to the branch selecting means 11, and the frequency conversion unit 91 and the demodulator 92 demodulate. Means 1
2, the level detecting unit 93 corresponds to the level measuring unit 13, the A / D converter 94 corresponds to the A / D converting unit 14, and the root roll-off filters 95 ₁ and 95 ₂ correspond to the band limiting unit 15. Then, the synthesizer 100 corresponds to the synthesizer 21. Hereinafter, the operation of this embodiment will be described.

Among the constituent elements of the present embodiment, the operation shown in FIG. 3 is the same as the operation in the embodiment corresponding to the invention described in claim 1, so that the description will be given here. Omit it. The combiner 100 sequentially takes in the signals supplied from the root roll-off filters 95 ₁ and 95 ₂ , combines them, and converts them into a demodulated signal indicating the latest signal point on the signal space. As for the method of the combining process performed by the combiner 100 in this way, if it is adapted to the transmission method of the wireless transmission path accessed by the antennas 161 ₁ and 161 ₂ , for example, the maximum ratio combining method, the notch detection type, or the like. Any combining method such as a combining method, a minimum amplitude deviation combining method, an in-phase combining method, etc. can be applied.

Therefore, according to the present embodiment, the hardware scale is reduced and the combining diversity method is applied under the common use of the frequency conversion unit 91, the demodulator 92 and the level detection unit 93 by a plurality of branches. You can FIG. 5 is a diagram showing an embodiment corresponding to the invention described in claim 3. In the figure, parts having the same functions and configurations as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted here.

The difference between the present embodiment and the embodiment shown in FIG. 3 is that a discriminator 110 is provided in place of the discriminator 96, and a demodulated signal DAT is obtained at one output and the other output is obtained. Is connected to the control input of the antenna switching control unit 97. The correspondence between the present embodiment and the block diagram shown in FIG. 6 is the same as the embodiment corresponding to the invention described in claim 1 except that the discriminator 110 corresponds to the signal determination means 16. Therefore, the description thereof is omitted here.

The operation of this embodiment will be described below. The operation of the components shown in FIG. 3 among the constituent elements of this embodiment is the same as the operation in the embodiment corresponding to the invention described in claim 1, and therefore the description thereof is omitted here. Similar to the discriminator 96 shown in FIG. 3, the discriminator 110 sequentially converts the signals supplied from the root roll-off filters 95 ₁ and 95 ₂ into demodulated signals indicating the closest signal points in the signal space. Further, the discriminator 110
Sequentially finds the deviation in the signal space in parallel with such conversion processing.

The antenna switching control unit 97 determines a magnitude relationship between such a deviation and an upper limit value determined in advance on the basis of the reliability of transmission information that is allowable, and when the former is less than the latter, The clock supply to the antenna switch 162 is stopped, and the antennas 161 ₁ , 1
The antenna switch 162 in the state of 62 ₂
A selection signal indicating one branch selected by is supplied to the discriminator 96, and the frequency of the clock to be supplied to the A / D converter 94 is set to a half value.

As described above, according to this embodiment, when the reliability of the received wave is high, the receiving operation is performed through any one of the branches, so that the operating speed of the A / D converter 94 is reduced. Power consumption is reduced. FIG. 6 is a diagram showing an embodiment corresponding to the invention described in claim 4. In the figure, parts having the same functions and configurations as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted here.

The difference between the present embodiment and the embodiment shown in FIG. 3 is that an antenna switching control unit 101 is provided instead of the antenna switching control unit 97, and the error output of the discriminator 96 is the line quality monitoring unit 102. Antenna switching control unit 1 via
01 is connected to the monitoring input. Regarding the correspondence relationship between the present embodiment and the block diagram shown in FIG. 2, the antenna switching control unit 101 and the antenna switch 62 correspond to the branch selecting unit 11, and the line quality monitoring unit 10 is provided.
The second embodiment is the same as the embodiment corresponding to the invention according to claim 2 except that the second embodiment corresponds to the synthesizing means 21, and therefore the description thereof is omitted here.

The operation of this embodiment will be described below. Note that the operation of the components shown in FIG. 3 among the components of this embodiment is the same as the operation in the embodiment corresponding to the invention described in claim 2, and therefore the description thereof is omitted here. The discriminator 96 is the root roll-off filter 9
The demodulated signals given via 5 ₁ and 95 ₂ are successively taken in to obtain an error in the signal space, and the line quality monitor unit 1
02 integrates the error and the antenna 16
The line quality of the wireless line accessed through 1 ₁ and 162 ₂ is obtained.

The antenna switching control unit 101 supplies a clock to the antenna switch 162 and the A / D converter 94 and a selection signal to the discriminator 96 in the same manner as the antenna switching control unit 97 in the embodiment shown in FIG. As described above, when the line quality obtained by the line quality monitor unit 102 is higher than a predetermined threshold value, the supply of the clock to the antenna switch 162 is stopped and the antenna 161 ₁ or 162 ₂ In the state, a selection signal indicating which one is selected by the antenna switch 162 is given to the discriminator 96. further,
The antenna switching control unit 101 sets the frequency of the clock to be supplied to the A / D converter 94 to half the value.

As described above, according to the present embodiment, since the receiving operation is performed through any one of the branches when the line quality is good, the operating speed of the A / D converter 94 is reduced and the consumption is reduced. You can save electricity. In addition, in the embodiment corresponding to the invention described in claims 3 and 4, the supply and the supply of the clock are interrupted and the frequency is increased or decreased. However, the present invention is not limited to such a configuration, and for example, Alternatively, the configuration may be such that reception is performed based on the diversity method by supplying the clock intermittently.

FIG. 7 is a diagram showing an embodiment corresponding to the invention described in claim 5. In FIG. In the figure, parts having the same functions and configurations as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted here. The difference between the present embodiment and the embodiment shown in FIG. 3 is that a microprocessor 111 that controls the operation of hardware (not shown) (for example, a transmission circuit and a display circuit) is provided. The output of is connected to the control input of the antenna switching control unit 97.

The correspondence relationship between this embodiment and the block diagrams shown in FIGS. 1 and 2 corresponds to the invention of claim 1 except that the fading monitor section 111 corresponds to the state identifying means 31. Since it is the same as the embodiment,
The description is omitted here. Hereinafter, the operation of the present embodiment will be described. Note that the operation of the components shown in FIG. 3 among the components of the present embodiment is the same as the operation in the embodiment corresponding to the invention described in claim 1, and therefore the description thereof is omitted here. Further, in the present embodiment, it is assumed that all the above-described constituent elements constitute a mobile station device of the mobile communication system.

The microprocessor 111 has the antenna 1
61 _1, 161 performed based on a predetermined been obtained procedures a radio channel setting control of a radio channel to be accessed through _2, the local station waiting state in accordance with the procedure (to wait for occurrence of a call related to the own station state) If you recognize that
This is notified to the antenna switching control unit 97. When the antenna switching control unit 97 receives such a notification, the antenna switching control unit 97 shown in FIG.
In the same manner as the antenna switching control unit 101 in the embodiment shown in FIG. 2, the clock supply to the antenna switch 162 is stopped, and _{one of} the antennas 161 ₁ and 162 ₂ that is selected by the antenna switch 162 in that state is selected. The signal is given to the discriminator 96, and
The frequency of the clock to be supplied to the A / D converter 94 is set to half the value.

As described above, according to the present embodiment, in the standby state, the receiving operation is performed through any one of the branches, and the operation speed of the A / D converter 94 is reduced, so that the power consumption is saved. It comes off. FIG. 8 shows claim 6.
FIG. 3 is a diagram showing an embodiment corresponding to the invention described in FIG. In the figure, components having the same functions and configurations as those shown in FIG. 7 are denoted by the same reference numerals, and description thereof is omitted here.

The difference between the present embodiment and the embodiment shown in FIG. 7 is that the microprocessor 111 is replaced by a remaining battery capacity monitoring section 121, and its monitoring input is connected to the terminal of the battery 122 (here, For simplicity, this is the anode terminal.)

The correspondence between the present embodiment and the block diagrams shown in FIGS. 1 and 2 is described in claims 1 and 2 except that the battery remaining capacity monitoring section 121 corresponds to the remaining capacity measuring means 41. Since it is the same as the embodiment corresponding to the invention, the description thereof is omitted here. Hereinafter, the operation of the present embodiment will be described.

The operation of the components shown in FIG. 7 among the components of this embodiment is the same as that of the embodiment corresponding to the invention described in claim 1, and therefore the description thereof is omitted here. . Further, in the present embodiment, it is assumed that all the above-described constituent elements constitute a mobile station device of the mobile communication system. Battery remaining capacity monitoring unit 121
Is set on the basis of the terminal voltage of the battery 122 and a predetermined lower limit value (the discharge characteristic of the battery 122 and the average current value supplied from the battery to the load). ) And the magnitude relationship with. Furthermore, when the former falls below the latter under such a determination, the battery remaining capacity monitoring unit 121 notifies the antenna switching control unit 97 to that effect. Antenna switching control unit 97
When such a notification is given, in the same manner as the antenna switching control unit 101 in the embodiment shown in FIG. 6, the clock supply to the antenna switch 162 is stopped,
A selection signal indicating which of the antennas 161 ₁ and 162 ₂ is selected by the antenna switch 162 in that state is given to the discriminator 96, and the frequency of the clock to be supplied to the A / D converter 94 is halved. Set.

As described above, according to this embodiment, when the remaining capacity of the battery 122 is below the predetermined lower limit value, the receiving operation is performed via any one of the branches,
Moreover, the operating speed of the A / D converter 94 is reduced. Therefore, for completed calls that have already occurred, the possibility that the call state will be maintained and the call state will be forcibly released within the range of deterioration of the call quality that is allowed based on the channel setting control procedure is kept low. To be

FIG. 9 is a diagram showing an embodiment corresponding to the invention described in claim 7. In FIG. In the figure, components having the same functions and configurations as those shown in FIG. 7 are denoted by the same reference numerals, and description thereof is omitted here. The difference between the present embodiment and the embodiment shown in FIG. 7 is that a fading monitor section 131 is provided in place of the microprocessor 111, and the output of the level detection section 93 is connected to its input.

Note that regarding the correspondence relationship between the present embodiment and the block diagram shown in FIG.
Is the same as the embodiment corresponding to the invention according to claim 1, except that it corresponds to the fading monitoring means 51.
The description is omitted here. Hereinafter, the operation of the present embodiment will be described. Note that the operation of the components shown in FIG. 7 among the constituent elements of this embodiment is the same as the operation in the embodiment shown in the figure, and therefore the description thereof is omitted here. Further, in the present embodiment, it is assumed that all the above-described constituent elements constitute a mobile station device of the mobile communication system.

The fading monitor unit 131 monitors the level measured by the level detection unit 93 and determines the magnitude relationship between the level of fluctuation and the frequency of the fluctuation with the threshold value set individually in advance. Further, when the former is lower than the latter under such a determination, the fading monitor unit 131 notifies the antenna switching control unit 97 to that effect.

When such notification is given, the antenna switching control section 97 is similar to the antenna switching control section 101 in the embodiment shown in FIG.
2, the clock supply to the antenna 2 is stopped, and the antenna 16
A selection signal indicating which of 1 ₁ and 162 ₂ is selected by the antenna switch 162 in that state is given to the discriminator 96, and the frequency of the clock to be supplied to the A / D converter 94 is set to a half value. .

As described above, according to this embodiment, when the fading associated with the received waves arriving at the antennas 161 ₁ and 162 ₂ is slight, the receiving operation is performed via any one of the branches, and A The operation speed of the / D converter 94 is reduced. Therefore, in a state where the transmission quality of the wireless transmission path is good, unnecessary power consumption is avoided.

An embodiment corresponding to the invention of claim 8 will be described below with reference to FIG. The difference between the present embodiment and the embodiment corresponding to the invention described in claim 1 is that the outputs of the root roll-off filters 95 ₁ and 95 ₂ correspond to the inputs of the discriminator 96 and the corresponding inputs of the selector 98. Is connected to the output of the AGC control unit 99.
Is connected to the AGC input of the demodulator 92 via.

The operation of this embodiment will be described below. In this embodiment, the operation of each unit based on the diversity method is the same as that of the embodiment corresponding to the invention described in claim 1, and therefore the description thereof is omitted here.
The selector 98 takes in the demodulated signals of the respective branches obtained at the outputs of the root roll-off filters 95 ₁ and 95 ₂ in the process of such operation, and among these demodulated signals,
Select the higher level one by one. The AGC control unit 99 obtains the level of the demodulated signal selected in this way, and the demodulator 92 performs constant value control for keeping the level constant in parallel with the demodulation process.

As described above, according to this embodiment, the frequency converter 91, the demodulator 92, and the level detector 93 are shared by a plurality of branches, and the fluctuation of the level of the received wave is reduced or suppressed prior to the signal determination. Therefore, the reliability of the signal determination can be improved while reducing the scale of hardware.

FIG. 10 is a view showing an embodiment corresponding to the invention described in claim 9. In the figure, parts having the same functions and configurations as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted here. The difference between the present embodiment and the embodiment corresponding to the invention according to claim 8 is that the outputs of the root roll-off filters 95 ₁ and 95 ₂ replace the AGC control unit 99 and the AGC control unit 14 is provided.
Directly connected to the inputs of 1 ₁ and 141 ₂ ,
The output of the C control unit is a selector 142 which replaces the selector 98.
It is connected to the AGC input of the demodulator 92 via the, and the selection input of the selector is connected to the selection output of the antenna switching control unit 97 together with the selection input of the discriminator 96.

Regarding the correspondence relationship between this embodiment and the block diagrams shown in FIGS. 1 and 2, the AGC control unit 14
1 _1, 141 ₂ corresponds to the monitoring means 71 ₁ -71 _N, the selector 142 except that corresponding to the selection means 72, claim 1
Alternatively, since it is the same as the embodiment corresponding to the invention described in claim 2, the description thereof is omitted here. Hereinafter, the operation of the present embodiment will be described.

In this embodiment, the operation of each unit based on the diversity method is the same as that of the embodiment corresponding to the invention described in claim 1, and therefore the description thereof is omitted here. The AGC control units 141 ₁ and 141 ₂ receive the root roll-off filter 9 in the process of such operation.
The levels of the demodulated signals of the respective branches obtained at the outputs of 5 ₁ and 95 ₂ are obtained in parallel. The selector 142 sequentially selects the level of the received wave arriving at the branch selected by the antenna switching control unit 97 from these levels, and the demodulator 92 performs constant value control for keeping the level constant in parallel with the demodulation processing. To do.

Therefore, in the present embodiment, similarly to the embodiment corresponding to the invention described in claim 8, it is possible to reduce or suppress the fluctuation of the level of the received wave while reducing the scale of hardware. Moreover, since the variation is detected in parallel for each branch, the reliability of signal determination is further improved.

FIG. 11 is a diagram showing an embodiment corresponding to the invention described in claim 10. In the figure, difference in configuration to the embodiment shown in FIG. 10, the antenna 161 _1, 1
61 ₂ individually corresponding to the demodulators 151 ₁ and 151 ₂ , and A
The D converters 152 ₁ and 152 ₂ are respectively the demodulator 9
2 and the A / D converter 94 instead of the AGC controller, and the AGC inputs of these demodulators are connected to the AGC control units 141 ₁ and 14 ₁ .
The output of 1 ₂ is directly connected.

The difference between the present embodiment and the block diagrams shown in FIGS. 1 and 2 lies in that the AGC controller 141 is different.
_1, 141 since ₂ is the same as the embodiment of the invention according to claim 1 or claim 2 except that corresponding to the monitoring means 81 ₁ to 81 _N, a description thereof will be omitted.
Hereinafter, the operation of the present embodiment will be described.

In this embodiment, the operation of each section based on the diversity method is the same as that of the embodiment corresponding to the invention described in claim 1, and therefore the description thereof is omitted here. Further, regarding the operation of reducing or suppressing the fluctuation of the level of the received wave, the demodulators 151 ₁ , 151 ₂
Are shown in parallel for each branch and shown in FIG.
Since the procedure is the same as that in 2, the description thereof is omitted here.

The received waves that are alternately given by the antenna switch 162 and converted into a predetermined intermediate frequency signal include the AGC control units 141 ₁ and 142 ₂ and the demodulator 151.
_The processing for reducing (suppressing) the level variation and the demodulation processing are individually performed by ₁ and 151 ₂ . The A / D converters 152 ₁ and 152 ₂ individually convert the demodulated signals obtained for each branch under such demodulation processing into digital signals and apply them to the root roll-off filters 95 ₁ and 95 ₂ .

That is, since the processing for reducing (suppressing) the fluctuation of the level of the received wave is performed in parallel in symbol units by individual hardware provided corresponding to each branch, fading associated with the received wave is performed. Even when the period of is short enough not to be ignored with respect to the time constant related to the above-mentioned constant value control, the transmission quality is stably and favorably maintained.

In each of the above-described embodiments, the antenna switch 162 selects a branch under the control of the antenna switching control unit 97, but the present invention is not limited to such a configuration and, for example, the operator It is also possible to limit the selection target to any one or a plurality of branches according to the state of a contact such as a switch that can be operated, or to increase or decrease the selection cycle appropriately.

In each of the above-described embodiments, the level of the received wave arriving at each branch is measured by the level detection unit 93 and given to the antenna switching control units 97 and 101. Not limited to the configuration, A
When the GC control is performed, for example, FIG. 3 and FIG.
As indicated by a dashed line at 0, the AGC control units 99 and 141
The level of the AGC control signal obtained at the outputs of ₁ and 141 ₂ may be given to the antenna switching control unit.

Further, in each of the above-described embodiments, the modulation system applied to the received waves arriving at the antennas 161 ₁ and 162 ₂ is the polyphase modulation system, and the demodulator 92 is the quadrature demodulation adapted to the modulation system. Although the processing is performed, the present invention is not limited to such a modulation method, and a wireless transmission to which a modulation method capable of frequency conversion or demodulation processing is applied while holding the band limitation that determines the reception band. Any system can be similarly applied.

[0088]

As described above, according to the first and second aspects of the present invention, the demodulation means is shared by a plurality of branches, thereby suppressing an increase in hardware scale and power consumption, and receiving these branches. Since the processing is done in parallel,
It becomes possible to flexibly cope with high-speed fading as compared with a receiving device of an antenna switching diversity system.

In the invention described in claims 3 to 5 and 7, the sharing of the demodulation means is carried out only in a state where fading or propagation loss which causes significant deterioration of transmission quality of the received wave arriving at each branch is involved. Therefore, the power consumed unnecessarily for the sharing in such a state is reduced. In the invention according to claim 6, since the demodulation means 12 is shared only when the remaining capacity of the battery exceeds the threshold value,
By setting the threshold value to a desired value in advance, the wireless transmission path is secured with priority over the transmission quality.

In the invention described in claims 8 to 10, since the transmission loss of the wireless transmission path provided with a plurality of branches and the variation thereof are reduced, the transmission quality is improved. Therefore, in the wireless transmission system to which these inventions are applied, the cost and size can be reduced, the running cost can be reduced, and the reliability of the transmission line can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the principle of the invention described in claims 1, 3 to 10.

FIG. 2 is a principle block diagram of the invention described in claims 2, 4 to 10.

FIG. 3 is a diagram showing an embodiment corresponding to the invention described in claims 1 and 8.

FIG. 4 is a diagram showing an embodiment corresponding to the invention described in claim 2;

FIG. 5 is a diagram showing an embodiment corresponding to the invention described in claim 3;

FIG. 6 is a diagram showing an embodiment corresponding to the invention described in claim 4;

FIG. 7 is a diagram showing an embodiment corresponding to the invention described in claim 5;

FIG. 8 is a diagram showing an embodiment corresponding to the invention described in claim 6;

FIG. 9 is a diagram showing an embodiment corresponding to the invention described in claim 7.

FIG. 10 is a diagram showing an embodiment corresponding to the invention of claim 9;

FIG. 11 is a diagram showing an embodiment corresponding to the invention of claim 10;

FIG. 12 is a diagram (1) illustrating a configuration example of a conventional receiving device.

FIG. 13 is a diagram for explaining the operation of the antenna diversity receiving system.

FIG. 14 is a diagram (2) illustrating a configuration example of a conventional receiving device.

[Explanation of symbols]

 11 branch selecting means 12 demodulating means 13 level measuring means 14 A / D converting means 15 band limiting means 16 signal judging means 21 combining means 31 state identifying means 41 remaining capacity measuring means 51 fading monitoring means 61, 71, 81 monitoring means 72 selection Means 91, 163, 171 Frequency converter 92, 151, 164, 172 Demodulator 93, 165, 173 Level detector 94, 152 A / D converter 95 Root roll-off filter 96, 110 Discriminator 97, 101, 166 Antenna switching Control unit 98,142 Selector 99,141 AGC control unit 100 Combiner 102 Line quality monitoring unit 111 Microprocessor 121 Battery remaining capacity monitoring unit 122 Battery 131 Fading monitoring unit 161 Antenna 162 Antenna switch 174 Selecting section

Claims (10)

[Claims] 1. Branch selection means for capturing a plurality of received waves individually arriving in a plurality of branches and sequentially and cyclically selecting these received waves at intervals of an integer fraction of a symbol period along a time axis. A demodulation means for demodulating a received wave selected by the branch selection means in a band wider than the occupied bandwidth of the received wave to obtain a demodulated signal; and a level of the received wave selected by the branch selection means. A level measuring means for measuring and a demodulated signal obtained by the demodulating means are A / D-converted while being separated at the timing of selection performed by the branch selecting means, and a plurality of digital signals individually corresponding to the plurality of branches. And A / D conversion means for obtaining the digital signal, and a plurality of digital signals obtained by the A / D conversion means are subjected to band limiting processing in parallel. Among the digital signals subjected to band limiting processing by the band limiting unit, the level measured by the level measuring unit is a band limiting unit that sets the reception bands of the plurality of received waves to be equal to or less than the occupied bandwidth. A receiving device, comprising: a signal determining means for selecting a maximum digital signal in symbol units and determining a signal point in a signal space. 2. Branch selection means for fetching a plurality of received waves individually arriving at a plurality of branches and sequentially and cyclically selecting these received waves at intervals of an integer fraction of a symbol period along a time axis. A demodulation means for demodulating a received wave selected by the branch selection means in a band wider than the occupied bandwidth of the received wave to obtain a demodulated signal; and a level of the received wave selected by the branch selection means. A level measuring means for measuring and a demodulated signal obtained by the demodulating means are A / D-converted while being separated at the timing of selection performed by the branch selecting means, and a plurality of digital signals individually corresponding to the plurality of branches. And A / D conversion means for obtaining the digital signal, and a plurality of digital signals obtained by the A / D conversion means are subjected to band limiting processing in parallel. , Band limiting means for setting the receiving bands of the plurality of received waves to be equal to or less than the occupied bandwidth, and combining the digital signals band-limited by the band limiting means on a symbol-by-symbol basis to obtain signal points in a signal space. A receiving device comprising: a synthesizing unit for making a determination. 3. The receiver according to claim 1, wherein the signal determining means includes means for determining a distance in a signal space between the digital signal whose signal point is determined and the signal point, and branch selecting means. In the case of determining the magnitude relationship between the distance obtained by the signal determining means or the average value of the distance and a preset threshold value, when the former falls below the latter, the selection is postponed, and when it exceeds the opposite. The receiving device, characterized in that it includes means for restarting the selection. 4. The receiving device according to claim 2, wherein the synthesizing means includes means for obtaining a vector sum of a plurality of digital signals whose signal points are determined and a distance in the signal space between the signal points. The branch selecting means determines the magnitude relationship between the distance obtained by the synthesizing means or the average value of the distance and a preset threshold value, and delays the selection when the former falls below the latter, and vice versa. A receiving device comprising means for resuming the selection when the number exceeds. 5. The receiving device according to claim 1, wherein a plurality of branches are arranged on the basis of a procedure of a wireless channel setting control method applied to a wireless transmission path. Of the received wave arriving at the branch of the state of the transmission quality is high or the degree of deterioration of the transmission quality is acceptable state identification means for identifying the state, the branch selection means, the state identification means by the state identification means A receiving apparatus comprising means for suspending or restarting selection according to whether or not any one of them has been identified. 6. The receiving device according to claim 1, further comprising a remaining capacity measuring unit that measures a remaining capacity of a battery that supplies driving power, and the branch selecting unit includes: A receiving device comprising means for comparing the remaining capacity measured by the remaining capacity measuring means with a threshold value given in advance, and suspending the selection when the former falls below the latter. 7. The receiving device according to claim 1, wherein the fluctuation range and cycle of the level measured by the level measuring means are monitored, and the fluctuation range and cycle are individually preliminarily measured. Fading monitoring means for judging whether or not it has fallen below a predetermined threshold value is provided, and the branch selecting means delays or restarts the selection depending on whether the result of the judgment made by the fading monitoring means is true or false. A receiving device comprising means. 8. The receiving device according to claim 1, further comprising a monitoring unit that obtains amplitudes in a signal space of a plurality of digital signals that have been band-limited by the band limiting unit. The receiving device is characterized in that the demodulating means includes means for increasing / decreasing a gain with the amplitude obtained by the monitoring means as a control amount and compressing a deviation of the amplitude. 9. The receiving apparatus according to claim 1, wherein a plurality of digital signals subjected to band limiting processing by the band limiting unit individually obtain amplitudes in a signal space, and the monitoring unit obtains the amplitudes. And a selecting unit that selects an amplitude corresponding to the digital signal selected by the signal determining unit, and the demodulating unit increases or decreases the gain by using the amplitude selected by the selecting unit as a control amount. A receiving apparatus comprising means for compressing an amplitude deviation. 10. The receiving device according to claim 1, wherein the demodulating means, the A / D converting means, and the band limiting means are made redundant corresponding to a plurality of branches individually. The plurality of digital signals band-limited by the band limiting unit is provided with a monitoring unit for individually obtaining the amplitude in the signal space, and the demodulating unit has the amplitude individually obtained by the monitoring unit as a control amount. A receiving apparatus comprising means for increasing or decreasing gains in parallel and compressing deviations of these amplitudes.