JP2005328505A - Diversity receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diversity receiver having a simple configuration which includes only one A/D conversion unit and receiving analog modulated signals. <P>SOLUTION: The diversity receiver includes: a switching unit 103 that analog-multiplexes signals received by two antennas 101a and 101b using time-division method, the switching unit being placed in front of an A/D conversion unit 104; a time-division separation unit 105 that obtains time-division multiplexed signals digitized by driving at the same frequency as driving frequency of the A/D conversion unit 104 and separates the time-divided signals into a signal per antenna 101a and 101b; signal quality judgement units 107a and 107b that judge each signal quality of time-divided signals; and a composition unit 108 that executes composition processing based on the signal quality. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a diversity receiver that uses two or more antennas to improve reception quality, and more particularly to a diversity receiver that receives analog modulated waves.

  Conventionally, diversity receivers that use two or more antennas to improve reception quality have been widely used regardless of broadcasting and communication, and their usefulness is widely known.

  On the other hand, a universal problem with such diversity receivers is that they must have multiple reception processing systems that support multiple antennas, especially for signals received from multiple antennas called phase combining diversity. In the diversity receiver of the method of adding and synthesizing by adjusting the phase, the configuration becomes complicated, and the cost for mounting becomes a problem.

  Further, when the demodulation process in the subsequent stage is realized by a digital method, an analog-digital conversion unit (hereinafter referred to as an AD conversion unit) that is expensive as a single component and occupies a large area when incorporated on an LSI chip. It is also known as a big problem that a plurality of names are required.

  Various solutions to such known problems have already been proposed. For example, in a diversity receiver that receives a digitally modulated signal wave having a relatively long symbol length, an AD conversion unit that has conventionally required two or more by providing a means for performing a switching process at a time interval that is half the symbol period Therefore, combining diversity processing can be realized with a simple configuration (see, for example, Patent Document 1).

Also, in diversity receivers that receive analog modulated waves, one or both signals from multiple antennas are subjected to phase adjustment processing by analog processing using an analog phase shifter, and then analog addition synthesis It is a well-known technique to take a configuration in which the signal is output to a demodulation processing unit by analog or digital processing at a later stage after performing (see, for example, Patent Document 2).
JP-A-5-175742 Japanese Patent Laid-Open No. 2001-267988

  However, in the above-described conventional diversity receiver, for example, in the technology disclosed in Patent Document 1, a characteristic unique to a digital modulation scheme is that a signal received in a relatively long time, which is a symbol period, is fixed in a certain pattern. Therefore, the subject of adaptation is limited to diversity receivers that receive digitally modulated waves, and there is a problem that it cannot be applied to reception of analog modulated signals.

  On the other hand, when phase synthesis is performed by analog processing as in the technique disclosed in Patent Document 2, high-accuracy parts are necessary because control by analog signals is necessary, and adjustment after mounting is necessary. There is a problem in terms of mounting cost.

  The present invention solves the above-described conventional problems, and is a diversity receiver that performs phase synthesis by a digital method, and can be realized with a simple configuration that requires only one AD conversion unit. An object of the present invention is to provide a diversity receiver that can also be applied to reception.

  In order to solve the above-described problem, a diversity receiver according to the present invention is a diversity receiver that combines signals received from N antenna terminals (N is a positive integer equal to or greater than 2). Switching means for sequentially switching signals received at the N antenna terminals and outputting them as one signal, and converting the signals output from the switching means into a time-division multiplexed digital signal An AD conversion means; a time division separation means for separating the digital signal converted by the AD conversion means into the N signals; and a switching means, the AD conversion means and the time division separation means. Timing connected to drive the switching means, the AD conversion means, and the time division separation means with a timing signal of the same frequency. Characterized in that it comprises a grayed generation means.

  Moreover, the diversity receiver according to the present invention is characterized by comprising one each of the switching means, the AD converting means, and the time division separating means.

  With these configurations, the diversity receiver according to the present invention can share a single AD conversion unit for processing signals from a plurality of antennas by using a switching unit, and has a specific symbol data structure. Since a multiplexing method that does not depend on the received signal is used, it is possible to synthesize a received signal regardless of whether it is a digital modulation wave or an analog modulation wave.

  In order to achieve the above object, the present invention can be implemented as a diversity reception method using characteristic configuration means of the diversity receiver as a step, or as a vehicle equipped with the diversity receiver.

  ADVANTAGE OF THE INVENTION According to this invention, the diversity receiver which performs the digital phase synthesis | combination applicable to an analog modulation wave and a digital modulation wave is realizable with the cheap structure which uses only a single AD conversion part.

  Hereinafter, embodiments of a diversity receiver according to the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a diversity receiver according to Embodiment 1 of the present invention. In the following description, the case where two antennas are connected (that is, N = 2) will be described as an example for simplicity, but the present invention is not necessarily limited to this.

  Further, the diversity receiver according to the first embodiment is characterized in that the intermediate frequency signal obtained from the two antenna signals is synthesized by using only a single AD conversion unit.

  In FIG. 1, the diversity receiver includes antenna terminals 101a and 101b, frequency conversion / IF processing units 102a and 102b connected to the antenna terminals 101a and 101b, a switching unit 103, an AD conversion unit 104, a time division separation unit 106, From the timing generation unit 105 connected to the switching unit 103, the AD conversion unit 104, and the time division separation unit 106, the signal quality determination units 107a and 107b connected to the time division separation unit 106, the synthesis unit 108, and the demodulation unit 109, respectively. It is configured.

  The signal received at the antenna terminal 101a is converted to a predetermined intermediate frequency by the frequency conversion / IF processing unit 102a, filtered to a predetermined bandwidth, and then input to the first input of the switching unit 103. Similarly, a signal received at the antenna terminal 101b is converted to a predetermined intermediate frequency by the frequency conversion / I / F processing unit 102b, filtered to a predetermined bandwidth, and then input to the second input of the switching unit 103.

  The switching unit 103 sequentially switches and outputs signals input from the two inputs according to the timing signal generated by the timing generation unit 105. The switching frequency is generally N times the sampling frequency required in the processing of the demodulator 109. In the present embodiment, the case where there are two antennas is described. Is preferred. The output of the switching unit 103 is a signal in which the signal corresponding to the antenna terminal 101a and the signal corresponding to the antenna terminal 101b are multiplexed in a time division format at an analog signal level.

  The AD conversion unit 104 converts the analog signal switched and output by the switching unit 103 into a digital signal in synchronization with the timing signal supplied from the timing generation unit 105.

  FIG. 2 is a schematic diagram showing an outline of input / output signals of the AD conversion unit 104. In FIG. 2A, the analog signal 901 and the analog signal 902 schematically show examples of analog signals input to the first and second inputs of the switching unit 103. An analog value obtained by alternately sampling the analog signal 901 and the analog signal 902 is output to the output of the switching unit 103, and this is input as an input analog signal to the AD conversion unit 104. The AD conversion unit 104 sequentially converts the input analog signal into a digital signal, and as a result, corresponds to the signal from the antenna terminal 101a as shown by the digital signal 903 in FIG. 2B as the output of the AD conversion unit 104. A signal in which the digital signal value and the digital signal value corresponding to the signal from the antenna terminal 101b are alternately arranged in a time-division format every other sample is obtained.

  Hereinafter, the configuration of the diversity receiver according to the first embodiment will be described with reference to FIG. 1 again. The output signal from the AD conversion unit 104 described above is converted into a digital signal value corresponding to the signal from the antenna terminal 101a and the signal from the antenna terminal 101b so that the time division separation unit 106 can perform subsequent processing. Are separated again into digital signal values corresponding to. This is because the subsequent processing such as phase addition synthesis processing requires processing between samples for each signal from each antenna, so that the data structure as shown in the digital signal 903 in FIG. 2B is inappropriate. Because there is.

  Then, the received signal separated into signals for each antenna terminal by the time division separation unit 106 is input to the corresponding signal quality determination units 107a and 107b.

  The signal quality determination units 107a and 107b mainly determine the reception level by using the received signal strength, and determine the signal quality from each antenna terminal.

  The synthesis unit 108 adds and synthesizes the output from the time division separation unit 106 while adjusting the phase and level based on the signal quality index information output from the signal quality determination units 107a and 107b to obtain an output signal. .

  The demodulator 109 demodulates the signal output from the synthesizer 108 to obtain a final demodulated signal.

  With the above configuration, the intermediate frequency signal obtained from the two antenna signals can be synthesized only by using the single AD conversion unit 104, and diversity that can be applied to an analog signal with a simple and inexpensive configuration. A receiver can be realized.

  In the above description, the signal quality is determined by one signal quality determination unit 107a and 107b for each signal corresponding to each antenna output from the time division separation unit 106. When the determination is made only by the signal intensity of each sample, a single determination unit can be used in a time division manner. The configuration in such a case is shown in the block diagram of FIG.

  FIG. 3 shows a circuit configuration diagram of a diversity receiver including the time division signal quality determination unit 110. In FIG. 3, the same components as those in FIG. As shown in FIG. 3, when the signal quality determination process is a time division process, a time division signal quality determination unit 110 is arranged at the output of the AD conversion unit 104 as an alternative to the signal quality determination units 107a and 107b in FIG. It becomes composition.

  With such a configuration, the implementation of the time division signal quality determination unit 110 is slightly limited, but a diversity receiver can be realized with a simpler configuration.

(Embodiment 2)
Hereinafter, a second embodiment of the diversity receiver according to the present invention will be described with reference to the drawings. The diversity receiver according to the second embodiment is characterized in that only a single AD conversion unit is used to convert a received signal from an antenna into a digital signal without performing frequency conversion processing. Is.

  FIG. 4 is a block diagram showing a configuration of the diversity receiver according to the second exemplary embodiment of the present invention. In FIG. 4, the same components as those in FIG. Further, the diversity receiver according to the second embodiment has a frequency conversion / IF processing unit that is omitted from the configuration of FIG. 1, and after the processing of the time division separation unit, a mixer, a local oscillator, And a decimation section.

  The diversity receiver according to the second embodiment of the present invention shown in FIG. 4 is configured to input the signal input from the antenna terminal to the switching unit 103 without frequency conversion. Further, mixers 201a and 201b connected to the local oscillator 202 are connected to the output of the time division separation unit 106, and decimation units 203a and 203b are connected to the outputs of the mixers 201a and 201b, and the decimation units 203a, The signal quality determination units 107a and 107b and the synthesis unit 108 are connected to the output of 203b.

  According to such a configuration, the received signals received at the antenna terminals 101a and 101b are the same as those in the first embodiment described above by the switching unit 103, the AD conversion unit 104, the timing generation unit 105, and the time division separation unit 106. The same processing is performed and output to the mixers 201a and 201b. However, in the second embodiment, the frequency of the timing signal generated by the timing generation unit 105 is N times the sampling frequency required in the mixers 201a and 201b, that is, twice the frequency when there are two antennas. It is appropriate to do.

  Then, the signals corresponding to the antenna terminals 101a and 101b output from the time division separation unit 106 are mixed with the signals generated by the local oscillator 202 in the mixers 201a and 201b, respectively, and converted into baseband signals or intermediate frequency signals. Converted. The sampling frequency of the signals output from the mixers 201a and 201b is a frequency necessary for the mixing process in the mixers 201a and 201b, and is higher than the sampling frequency necessary for the demodulation in the demodulation unit 109. Therefore, the decimation unit 203a And 203b are subjected to decimation processing and filter processing, and input to signal quality determination sections 107a and 107b and synthesis section.

  The signal quality determination units 107a and 107b determine the signal quality from each antenna terminal, the synthesis unit 108 outputs the output from the time division separation unit 106, and the signal quality indicator information output from the signal quality determination units 107a and 107b. The output signal is obtained by adding and synthesizing while adjusting the phase and level. The demodulation unit 109 demodulates the signal output from the configuration unit 108, and a final demodulated signal is obtained.

  With the configuration as described above, it is possible to convert analog reception signals from the antennas 101a and 101b into digital signals without using frequency conversion processing, using only a single AD conversion unit 104. Since the corresponding diversity receiver can be realized with a simple configuration, it is particularly useful for implementation as a system LSI.

(Embodiment 3)
Hereinafter, a third embodiment of a diversity receiver according to the present invention will be described with reference to the drawings. Note that the diversity receiver according to the third embodiment uses a single AD converter with a simpler configuration and converts the received signal from the antenna into a digital signal without performing frequency conversion processing. It is characterized by that.

  FIG. 5 is a block diagram showing a configuration of a diversity receiver according to the third embodiment of the present invention. In FIG. 5, the same components as those in FIG. In the third embodiment, the mixer 201 is arranged between the AD conversion unit 104 and the time division separation unit 106, and the output of the time division separation unit 106 is connected to the decimation units 203a and 203b.

  Similarly to the diversity receiver in the second embodiment described above, the output of the AD conversion unit 104 is multiplied by the number of antennas of the sampling frequency originally required in the mixer processing, that is, in the configuration of FIG. Therefore, the received signals corresponding to the antenna terminals 101a and 101b are alternately output in the time division multiplexing format at twice the frequency.

  In the third embodiment, the mixer 201 and the local oscillator 202 operate at the same frequency as the AD conversion unit 104, and the mixer 201 inputs the output of the AD conversion unit 104 and mixes it with the signal generated by the local oscillator 202. Processing is performed to output a baseband or intermediate frequency signal arranged in a time division multiplex format. The time division separation unit 106 separates this signal into a signal corresponding to each antenna terminal, and outputs it to the decimation units 203a and 203b.

  Since the subsequent processing is exactly the same as the operation of the diversity receiver in the second embodiment already described, the description thereof is omitted.

  With the configuration as described above, although the number of components that require high-speed processing increases, the received signals from the antennas 101a and 101b are subjected to frequency conversion processing using only a single AD conversion unit 104 with a simpler configuration. Therefore, it is possible to realize a diversity receiver that can also convert to a digital signal and process analog modulated waves.

  FIG. 6 is an external view of a vehicle 600 provided with a diversity receiver 601 according to the present invention. As shown in the figure, a diversity receiver 601 according to the present invention can be used as a diversity receiver 601 that receives and synthesizes a radio or television broadcast wave from an antenna 602 in a vehicle, for example.

  In the description of each of the above embodiments, the case where the number of antennas (N) is two has been described. However, the number of antennas included in the diversity receiver according to the present invention is not limited to this. It goes without saying that the diversity receiver according to the present invention is applicable not only to reception of analog modulated waves but also digital modulated waves.

  The present invention can be applied to, for example, a diversity receiver that receives analog modulated waves such as AM broadcast and FM broadcast and performs digital signal processing thereof, or a system LSI that realizes diversity reception. The diversity receiver according to the present invention can be used for, for example, a vehicle-mounted diversity receiver that receives television and radio broadcasts, a portable terminal, a wireless LAN, and the like.

FIG. 1 is a block diagram showing a configuration of a diversity receiver in Embodiment 1 of the present invention. Schematic diagram showing the outline of the input / output signals of the AD converter Block diagram showing another configuration of the diversity receiver according to Embodiment 1 of the present invention. Block diagram showing a configuration of a diversity receiver in Embodiment 2 of the present invention Block diagram showing a configuration of a diversity receiver in Embodiment 3 of the present invention External view of a vehicle equipped with a diversity receiver according to the present invention

Explanation of symbols

101a, 101b Antenna terminals 102a, 102b Frequency conversion / IF processing unit 103 Switching unit 104 AD conversion unit 105 Timing generation unit 106 Time division separation unit 107a, 107b Signal quality determination unit 108 Synthesis unit 109 Demodulation unit 110 Time division signal quality determination unit 201, 201a, 201b Mixer 202 Local oscillator 203a, 203b Decimation unit 600 Vehicle 601 Diversity receiver 602 Antenna

Claims (10)

A diversity receiver that combines signals received from N antenna terminals (N is a positive integer of 2 or more),
Switching means having the N inputs and sequentially switching signals received at the N antenna terminals and outputting them as one signal;
AD conversion means for converting the signal output from the switching means into a time-division multiplexed digital signal;
Time-division separating means for separating the digital signal converted by the AD converting means into the N signals and outputting them;
Timing generating means connected to the switching means, the AD converting means, and the time division separating means, and drivingly controlling the switching means, the AD converting means, and the time division separating means with a timing signal having the same frequency. A diversity receiver characterized by that. The diversity receiver according to claim 1, wherein the diversity receiver includes one each of the switching unit, the AD conversion unit, and the time division separation unit. The diversity receiver further includes:
The N frequency conversion / IF processing means connected to the N antenna terminals and converting a signal received at the antenna terminal into a predetermined frequency;
The N signal quality judging means for judging the signal quality of the signal output from the time division separating means;
A synthesizing unit connected to the time-division separating unit and the N signal quality determining units, and synthesizing the time-division signal based on the signal quality;
Demodulating means for demodulating the signal output from the synthesizing means,
The diversity receiver according to claim 1, wherein the N inputs of the switching means are connected to the N frequency conversion / IF processing means, respectively. The diversity receiver further includes:
A time-division signal quality determination means for determining the signal strength of the signal output from the AD conversion means;
The timing generation means is further connected to the time division signal quality determination means, and drives and controls the switching means, the AD conversion means, the time division separation means and the time division signal quality determination means with the timing signal,
The diversity receiver according to claim 3, wherein the combining means is connected to the time division signal quality determination means and the time division separation means, and combines the time division signals based on the signal strength. . The diversity receiver according to claim 3, wherein the frequency of the timing signal generated by the timing generation unit is N times the sampling frequency used by the demodulation unit. The diversity receiver further includes:
The N mixers connected to the N outputs of the time division separation means;
A local oscillator connected to the N mixers;
The N decimation means connected to the output of each of the N mixers;
The N signal quality judging means connected to the output of each of the N decimation means;
Combining means connected to the N decimation means and the N signal quality determination means;
The diversity receiver according to claim 1, further comprising a demodulating unit that demodulates a signal output from the combining unit. The diversity receiver further includes:
A mixer connected to the AD conversion means;
A local oscillator connected to the mixer;
The N decimation means connected to the time division separation means;
Signal quality determination means connected corresponding to the outputs of the N decimation means;
Combining means connected to the N decimation means and the N signal quality determination means;
Demodulating means for demodulating the signal output from the synthesizing means,
The diversity receiver according to claim 1, wherein the time division separation unit separates an output from the mixer into the N signals and outputs the N signals to the N decimation units. A diversity reception method used in a diversity receiver that combines signals received from N antenna terminals (N is a positive integer of 2 or more),
A switching step of sequentially switching signals received at the N antenna terminals using the N inputs and outputting the signals as one signal;
An AD conversion step for converting the signal output in the switching step into a time-division multiplexed digital signal;
A time-division separation step for separating the digital signal converted in the AD conversion step into the N signals and outputting them;
A diversity receiving method, characterized in that the processing in the switching step, the AD conversion step, and the time division separation step includes a timing generation step in which drive control is performed with a timing signal having the same frequency. The diversity reception method further includes:
Using the N antenna terminals, a frequency conversion / IF processing step for converting a signal received at the antenna terminals into a predetermined frequency;
A signal quality determination step for determining the signal quality of the signal output in the time division separation step;
After the time division separation step and the signal quality determination step, a synthesis step for synthesizing the time division signal based on the signal quality;
The diversity reception method according to claim 8, further comprising a demodulation step of demodulating a signal output in the combining step.   A vehicle comprising the diversity receiver according to claim 1.

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