JP5759422B2 - Receiver and receiving method - Google Patents

Description

  The present invention relates to a technique for performing communication using a plurality of radio bands.

  With the diversification of uses of wireless communication, a receiver (multiband receiver) that can receive signals in a plurality of frequency bands is required to have a wider reception band. The configuration of a multiband receiver includes a configuration in which the number of radio frequency bands that can be received simultaneously is limited and a required number of receiving circuits are provided (for example, see Non-Patent Document 1).

  However, in the configuration in which the receiving circuit is provided according to the radio frequency band as in Non-Patent Document 1, there arises a problem that the circuit scale increases as the corresponding radio frequency band increases.

  On the other hand, a configuration of a receiver that can reduce an increase in circuit scale even when the corresponding radio frequency band is increased has been proposed (see, for example, Patent Document 1). Specifically, it is a receiver that performs frequency conversion of signals included in a plurality of radio frequency bands, generates a plurality of local oscillation signals, and adjusts the power of each signal to adjust the frequency of the plurality of radio frequency bands. Are converted simultaneously, and the conversion gain for each band is independently controlled.

International Publication No. 2011/0807016

Ito et al., “Thorough research on mobile phones and their systems”, CQ Publishing, RF World, No. 2, p57, April 2008

  As described above, the technique of Patent Document 1 has advantages such as being effective in reducing the circuit scale of the receiver and being able to independently control the frequency conversion gain for each band. However, when the radio frequency band received simultaneously increases, there is a problem that mixing between local signals increases, and unnecessary waves are mixed in the reception IF frequency.

  In view of the above circumstances, an object of the present invention is to provide a technique for reducing unnecessary waves generated by mixing between local signals even when the corresponding radio frequency band is increased.

One aspect of the present invention, the frequency conversion for the frequency conversion of the frequency of the radio frequency band of the multiple using a plurality of local oscillation signal generator for generating a local oscillation signal having a plurality of different frequencies, the plurality of local oscillation signals And the plurality of local oscillation signal generators are integer multiples of a certain base frequency, and the frequency of a certain local oscillation signal is not an integral multiple of the frequency of another local oscillation signal, and is The receiver generates the plurality of local oscillation signals so as to satisfy a condition that the frequencies of two or more local oscillation signals do not match the sum and difference of the frequencies of the other local oscillation signals.

  One aspect of the present invention is the above-described receiver, wherein the plurality of local oscillation signal generation units have a frequency of one local oscillation signal that is equal to or less than K (K is an integer of 2 or more) of the frequency of another local oscillation signal. The plurality of local oscillation signals are generated so as to satisfy the condition that they are not integral multiples of.

  One aspect of the present invention is the above-described receiver, wherein the plurality of local signal generation units include a certain L order (L is 2 or more) in which a frequency of a certain local signal is a plurality of other local signal frequencies. The plurality of local oscillation signals are generated so as to satisfy the condition that they do not match the sum and difference of the integers).

  One aspect of the present invention is the above-described receiver, wherein the base frequency is set to at least twice the bandwidth of the intermediate frequency extracted after frequency conversion by the frequency conversion unit.

One aspect of the present invention, the frequency conversion for the frequency conversion of the frequency of the radio frequency band of the multiple using a plurality of local oscillation signal generation step of generating a local oscillation signal having a plurality of different frequencies, the plurality of local oscillation signals A plurality of local oscillation signal generation steps, wherein the local oscillation signal frequency is an integer multiple of a certain base frequency, and the frequency of a certain local oscillation signal is not an integral multiple of the frequency of another local oscillation signal; and In this receiving method, the plurality of local oscillation signals are generated so as to satisfy the condition that the frequencies of two or more local oscillation signals do not match the sum and difference of the frequencies of the other local oscillation signals.

  According to the present invention, it is possible to reduce unnecessary waves generated by mixing between local signals even when the corresponding radio frequency band is increased.

It is a block diagram which shows the specific example of the one part structure of the receiver 1 by one Embodiment of this invention. It is a block diagram which shows the structural example of the receiver 1 by this embodiment. It is a conceptual diagram for demonstrating the rule of the frequency setting of the local oscillation signal of the local oscillation signal production | generation part 10-1 to 10-N by this embodiment. It is a conceptual diagram which shows an example of the frequency setting of the local signal of the local signal generation part 10-1 to 10-N of the receiver 1 by one Embodiment of this invention. It is a conceptual diagram which shows the specific example of the received signal spectrum at the time of setting the frequency of a local oscillation signal based on the frequency setting rule of a local oscillation signal by this embodiment. It is a conceptual diagram which shows the received signal spectrum at the time of performing the frequency setting of the local oscillation signal which deviated from the frequency setting rule by this embodiment. It is a conceptual diagram for demonstrating the advantage in case the receiver 1 by this embodiment is actually used. It is a block diagram for demonstrating the advantage of reducing the interference of the local oscillation signal corresponding to another band in the receiver 1 by this embodiment. It is a flowchart which shows the procedure of the frequency setting method in the local signal generation part 10-1 to 10-N of the receiver 1 by this embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a specific example of a partial configuration of a receiver 1 according to an embodiment of the present invention. The receiver 1 includes local oscillation signal generators 10-1, 10-2,..., 10-N (N is an integer of 2 or more), power adjusters (ATT) 11-1, 11-2,. N and the frequency converter 12 are provided. Local oscillation signal generating unit 10-1 to 10-N generates and outputs a plurality of local oscillation signal (local oscillation _signal) of the frequency LO 1 ~LO _N. Local oscillation signal _{LO 1, LO 2, ...,} LO N has each frequency _{F 1,} F 2, ..., a _{F N.} The power adjustment units 11-1, 11-2,..., 11-N control the power of the local signals supplied from the local signal generation units 10-1 to 10-N according to predetermined settings, respectively. Output to the frequency converter 12. The frequency conversion unit 12 performs frequency conversion processing on the reception signal RF received by the antenna. The frequency conversion unit 12 performs frequency conversion on the reception signal RF in accordance with the local oscillation signals LO _{1 to} LO _N. The frequency converter 12 arranges and outputs the received signal RF at a desired frequency in the baseband or intermediate frequency (IF) band.

FIG. 2 is a block diagram illustrating a configuration example of the receiver 1 according to the present embodiment. 1 are denoted by the same reference numerals as those in FIG. 1 and description thereof is omitted.
The antenna 13 receives radio waves. Hereinafter, the radio wave received by the antenna 13 is referred to as a received signal. A plurality of signals with different frequency bands are superimposed on the received signal. A high frequency amplifier (LNA: Low Noise Amplifier) 14 amplifies the received signal. The demultiplexer / distributor 15 divides the received signal into a plurality of predetermined frequency bands and outputs them. The frequency conversion units 12-1 to 12 -N correspond to the frequency conversion unit 12. Frequency conversion section 12-1 to 12-N are generated by the local oscillation signal generating unit 10-1 to 10-N, the local oscillation signals _LO 1 ~ supplied via the power adjuster 11-1 to 11-N It receives an input of LO _N. Frequency conversion section 12-1 to 12-N, in accordance with the inputted local oscillation signal _LO 1 _{~LO N,} performs frequency conversion on the received signal RF. The frequency converters 12-1 to 12 -N arrange and output the reception signal RF of each frequency band output by the demultiplexer / distributor 15 at a desired frequency in the baseband or intermediate frequency (IF) band. . The synthesizer 16 synthesizes and outputs the signals output from the frequency conversion units 12-1 to 12-N. The low pass filter (LPF) 17 removes high frequency components from the signal (received signal) output by the synthesizer 16. The variable gain amplifier 18 amplifies the received signal from which the high frequency component has been removed. The variable gain amplifier 18 outputs the amplified received signal to a subsequent circuit (not shown).

FIG. 3 is a conceptual diagram for explaining the rules for setting the frequency of the local signal of the local signal generators 10-1 to 10-N according to the present embodiment. In FIG. 3, the horizontal axis indicates the frequency. The frequencies F ₁ , F ₂ , F ₃ ,..., F _N are the frequencies of the local signals of the local signal generators 10-1 to 10 -N with respect to the base frequency F ₀ . The base frequency F ₀ is set to, for example, twice or more the bandwidth of the intermediate frequency extracted after frequency conversion by the frequency conversion unit 12.

The frequencies F ₁ , F ₂ , F ₃ ,..., F _N of the multi-station signals are set under the following conditions.
(R1) It is an integer multiple of the base frequency F ₀ , and when the integer value is M _{1 to MN} ,
(R2) M _{1 to MN} are all integers of 2 or more. (R3) LOs do not have an integer multiple relationship (M _K is not a multiple of M _{1 to} M _K−1 ).
(R4) The sum or difference of a certain L order (L is an integer of 2 or more) between two or more LOs does not match other LOs.
M _A + M _B ≠ M _C (second-order sum; L = 2)
M _A −M _B ≠ M _C (second order difference; L = 2)
M _A −M _B + M _C ≠ M _D (third-order sum difference; L = 3)
2M _A −M _B ≠ M _C (third-order sum difference; L = 3)
The base frequency F ₀ and the frequencies F ₁ , F ₂ , F ₃ ,..., F _{N of} the multiple local signals are determined by the local signal generator 10.

In the local oscillator signal generation unit 10-1 to 10-N, frequencies _F 1 of the local oscillator _{signal, F 2, F 3, ...} , the _{F N,} is set to an integral multiple of a base frequency _{F 0.} Such processes, unnecessary signal generated by the mixing between the local oscillator signal occurs only integer multiples of the base frequency F _0. Therefore, the number of unnecessary wave spectra can be reduced.

  Further, the local oscillation signals do not have an integer multiple relationship. As a result, the harmonics of the low frequency local oscillation signal (generated in the frequency band of an integral multiple of 2 times, 3 times,...) Do not overlap with the frequency of other local oscillation signals. Therefore, by controlling the relative power of the local oscillation signal, the influence of unnecessary waves of other local oscillation signals can be reduced when the conversion gain for each band is controlled. Therefore, the gain control range can be further increased.

  Similarly, by setting the frequency so that the sum or difference between two or more local oscillation signals does not match other local oscillation signals, the influence of unwanted waves caused by local oscillation signals corresponding to other bands can be reduced. Can be reduced. Therefore, the gain control range can be further increased.

FIG. 4 is a conceptual diagram illustrating an example of the frequency setting of the local signal of the local signal generation units 10-1 to 10-N of the receiver 1 according to the embodiment of the present invention. A frequency setting method is adopted that suppresses unwanted waves between LOs and realizes independent control of conversion gain. A base LO frequency that is not input is set, and the frequencies of LO ₁ , LO ₂ , and LO ₃ are set so as to be an integral multiple thereof. Further, the frequency is set so that the rules (R1) to (R4) are satisfied. The LO setting can be replaced with an integer problem, and unnecessary waves can be suppressed.

When the frequencies F ₁ , F ₂ , F ₃ of the plurality of local oscillation signals are integer multiples of (r1) base frequency F ₀ , and the integer values are 5, 14, 36,
(R2) M _{1 to MN} are all integers of 2 or more.
(R3) LOs do not have an integer multiple relationship.
That is, 14 is not a multiple of 5.
Also, 36 is not a multiple of 5 and 14.
(R4) The sum or difference between two or more LOs does not match other LOs.
That is, 5 + 14 = 19 ≠ 36
36−5 = 31 ≠ 14
Also, 36-14 = 12 ≠ 5
And rules (R1) to (R4) are satisfied.

  FIG. 5 is a conceptual diagram showing a specific example of the received signal spectrum when the frequency of the local oscillator signal is set based on the frequency setting rule of the local oscillator signal according to the present embodiment. FIG. 5 shows a received signal spectrum obtained by frequency-converting signals in three radio frequency bands of 315 MHz band, 920 MHz band, and 2.4 GHz band to IF frequency bands from DC to 25 MHz based on the frequency setting rule. . FIG. 6 is a conceptual diagram showing a received signal spectrum when the frequency setting of the local signal deviating from the frequency setting rule according to the present embodiment is performed.

  As shown in FIGS. 5 and 6, when the frequency setting of the local oscillation signal is performed according to the above-described frequency setting rule, the frequency of the unnecessary wave is smaller than when the frequency setting of the local oscillation signal deviates from the frequency setting rule. Occurrence has been reduced. Further, no interference signal is generated in the IF frequency band from DC to 25 MHz. Thus, FIG. 5 shows the effectiveness of the frequency setting rule of the present invention.

Rule (R3) sum and difference are two or more LO each other that do not match the other LO, that is, when considered to infinity of combinations, some kind of component to an integral multiple of the frequency of the base frequency F ₀ generated It is expected that. However, since it is caused by the non-linearity of the frequency converter, the power of higher-order sum and difference components becomes lower. Since these nonlinear components exist, the range of conversion gain control by controlling the power of the LO signal is narrowed, but conversion gain control is possible.

  FIG. 7 is a conceptual diagram for explaining advantages when the receiver 1 according to the present embodiment is actually used. As shown in FIG. 7A, the receiver 1 according to the present embodiment receives signals in a plurality of radio frequency bands coming from a PC (Personal Computer) 20, a mobile phone 21, an electronic device 22, and the like with various power differences. Are received at the same time. The received signal is represented by a spectrum as shown on the left side of FIG. Even when signals in a plurality of radio frequency bands with power differences are received simultaneously, the power difference can be reduced in the frequency-converted IF band as shown in the approximate center of FIG. it can. Therefore, the number of bits in the analog / digital converter (A / D) 19 can be reduced. Furthermore, the amount of data when digitized can be reduced. In the receiver 1 shown in FIG. 7A, the power adjustment units 11-1 to 11-3 are configured to control the conversion gain for each band by the relative power ratio of the LO power.

  FIG. 8 is a block diagram for explaining the advantage of reducing the interference of local signals corresponding to other bands in the receiver 1 according to the present embodiment. The components shown in FIG. 2 are denoted by the same reference numerals as those in FIG. 2 in FIG. Even if the receiver 1 includes a plurality of frequency conversion units 12-1 to 12-N, the components of the local oscillation signal can be distributed / combined even if the configuration corresponds to each radio frequency. May wrap around. Even in such a case, the interference of the local signal corresponding to the other band can be reduced by the frequency setting method according to the present embodiment.

FIG. 9 is a flowchart showing the procedure of the frequency setting method in the local signal generators 10-1 to 10-N (hereinafter simply referred to as “local signal generator 10”) of the receiver 1 according to the present embodiment. . First, the local signal generator 10 obtains the frequency of the received RF signal (received signal) and the bandwidth information (step S1). Next, the local signal generator 10 sets the frequency and bandwidth of the IF signal (step S2). Next, the local signal generator 10 sets a base LO frequency (step S3). Next, the local oscillation signal generation unit 10 sets the LO _{1 to} LO _N frequencies so as to be an integer multiple (2 or more) of the set base LO frequency (step S4). Thereby, the rules (R1) and (R2) are satisfied.

Next, the local oscillation signal generation unit 10 determines whether or not each of the LO _{1 to} LO _N frequencies is an integer multiple of L or less (step S5). When the LO _{1 to} LO _N frequencies are integer multiples of L times or less (step S5-YES), the local signal generator 10 does not satisfy the rule (R3) (interference between LO signals). Therefore, it is necessary to review), and the process returns to step S2 to perform resetting.

On the other hand, when the LO _{1 to} LO _N frequencies are not integer multiples equal to or less than L times (step S5-NO), the local oscillation signal generator 10 satisfies the rule (R3), and therefore performs the next processing. Transition. The local signal generator 10 determines whether or not the L-order sum and difference of two or more LO signals match the frequency of another LO signal (step S6). When the L-order sum and difference of two or more LO signals match the frequency of another LO signal (step S6-YES), the local oscillation signal generator 10 does not satisfy the rule (R4) (LO Since the interference between the signals is large, review is required), the process returns to step S2 and resetting is performed.

On the other hand, if the L-order sum and difference of two or more LO signals do not match the frequency of the other LO signals (step S6-NO), the local oscillation signal generator 10 satisfies the rule (R4). Therefore, the process ends.
As described above, the frequency setting in the local oscillation signal generator 10 can be automated by programming or the like.

According to the above-described embodiment, (R1) When the frequencies F _{1 to} F _N of the multi-station oscillation signals are integer multiples of a certain base frequency F ₀ , and the integer values are M _{1 to MN} , R2) M _{1 to MN} are all integers of 2 or more, (R3) LOs do not have an integer multiple relationship, and (R4) the sum or difference between two or more LOs is different from other LOs. It is set based on the rule that does not match. As a result, even if the corresponding frequency band is increased, it is possible to reduce unnecessary waves caused by mixing between the local signals.

  In addition, a program for realizing the frequency setting in the local signal generators 10-1 to 10-N is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system. The frequency setting in the local oscillation signal generation units 10-1 to 10-N may be performed by executing. Here, the “computer system” may include an OS and hardware such as peripheral devices. Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used. The “computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a CD-ROM, a hard disk built in a computer system, etc. This is a storage device.

  Further, the “computer-readable recording medium” means a volatile memory (for example, DRAM (Dynamic DRAM) in a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Random Access Memory)), etc., which hold programs for a certain period of time. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Receiver, 10-1 to 10-N ... Local oscillation signal generation part, 11-1 to 11-N ... Power adjustment part (ATT), 12, 12-1 to 12-N ... Frequency conversion part, 13 ... Antenna: 14 ... high frequency, 15 ... demultiplexer / distributor, 16 ... synthesizer, 17 ... low pass filter, 18 ... variable gain amplifier, 19 ... A / D converter

Claims (5)

A plurality of local signal generators for generating local signals of a plurality of different frequencies;
And a frequency converter for frequency-converting the frequency of the radio frequency band of several using the plurality of the local oscillator signal,
The plurality of local oscillation signal generation units,
An integer multiple of some base frequency,
And the frequency of one local oscillator signal does not become an integral multiple of the frequency of another local oscillator signal,
The receiver generates the plurality of local oscillation signals so as to satisfy a condition that the frequencies of two or more local oscillation signals do not match the sum and difference of the frequencies of the other local oscillation signals. The plurality of local oscillation signal generation units,
The plurality of local oscillation signals are generated so as to satisfy a condition that a frequency of a certain local oscillation signal does not become an integer multiple of K (K is an integer of 2 or more) of a frequency of another local oscillation signal. As described in the receiver. The plurality of local oscillation signal generation units,
The plurality of local oscillation signals satisfy the condition that the frequency of a certain local oscillation signal does not match the sum and difference of a certain L order (L is an integer of 2 or more) at other local oscillation signal frequencies. The receiver according to claim 1 or 2. The base frequency is
The receiver according to any one of claims 1 to 3, wherein the receiver is set to at least twice the bandwidth of an intermediate frequency extracted after frequency conversion by the frequency conversion unit. A plurality of local signal generation steps for generating a plurality of local frequency signals from different frequencies;
And a frequency conversion step of frequency converting the frequency of the radio frequency band of several using the plurality of the local oscillator signal,
In the plurality of local signal generation steps,
An integer multiple of some base frequency,
And the frequency of one local oscillator signal does not become an integral multiple of the frequency of another local oscillator signal,
A receiving method for generating the plurality of local oscillation signals so as to satisfy a condition that the frequencies of two or more local oscillation signals do not match the sum and difference of the frequencies of the other local oscillation signals.

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