JP4230825B2 - Sampling apparatus and sampling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sampling device and a sampling method used in mobile communication such as a digital mobile phone. In particular, the present invention relates to a sampling method of an analog-digital conversion unit (AD conversion unit) of a multimode terminal that simultaneously receives a plurality of wireless systems.
[0002]
[Prior art]
Conventionally, by mounting a built-in wireless device or a card slot type wireless device on a digital cellular phone terminal, a notebook PC, or a PDA (hereinafter referred to as a receiver) and receiving signals simultaneously from a plurality of wireless systems, the user can Services related to voice calls and data communications are used seamlessly.
In a receiver using such digital signal processing, the received signal is AD converted at a sampling rate (clock frequency) corresponding to each wireless system (see Patent Document 1). Here, since the system clock of each wireless system is different, the sampling signal required for each wireless system is also different. In addition, the system clock of each wireless system may not be synchronized between the wireless systems. For this reason, in order to simultaneously receive and process a plurality of wireless systems, it is conceivable to prepare an AD conversion unit for each wireless system and perform AD conversion (see Patent Document 2).
[0003]
In addition, the signals of each wireless system are arranged on the frequency axis before the input of the AD conversion unit, put together and input to the AD conversion unit, and the AD at the sampling rate of the system that requires the fastest sampling rate. It is conceivable to convert the signal to a sampling rate necessary for each system by signal processing.
This will be described with reference to the figure. An added signal obtained by adding the output signal (reception signal) of the RF / IF converter (RF → IF) of each of the wireless systems A to C (Systems A to C in the figure) is converted into an AD converter ( Sampler (AD Converter)).
The input addition signal is sampled with a fixed sampling clock set in advance based on the system clock of each of the wireless systems A to C. For example, if the system clock frequency of the wireless system A is the highest, the input addition signal is sampled based on the system clock of the wireless system A.
[0004]
The sampled digital signal is input to an IF unit (Digital IF or Timing Sync) of each wireless system after necessary digital filter processing.
At this time, regarding the wireless system A, since the system clock and the digital signal are already synchronized in the AD converter, they are down-sampled by the decimator and input to the IF unit.
On the other hand, with respect to the wireless systems B and C, since the system clock and the sampled digital signal are not synchronized in the AD conversion unit, the wireless system B is sampled by a sampling rate converter (Sampling Rate converter) in the previous stage of the IF unit. , The sampling frequency is converted based on the C system clock.
[0005]
[Non-Patent Document 1]
“Sample Rate Conversion for Software Radio”, IEEE Communication Magazine August 2000, p. 142-150
[Non-Patent Document 2]
Junichi Araki, “Basics and Applications of Software Defined Radio”, October 31, 2002, Knowledge Service Business Division, Cybex Corporation, p. 166-177
[0006]
[Problems to be solved by the invention]
However, in the former case, there is a problem that a plurality of AD conversion units are required, which increases power consumption and component space.
In the latter case, only one AD converter is required, but a sampling rate converter is required for each wireless system. In particular, when the sampling rate of the AD conversion unit and the rate ratio of the wireless system are irrational numbers, there is a problem that performance degradation and processing for compensating for it are necessary.
Further, in order to synchronize the sampling timing with the symbol of the wireless system, each system requires processing for obtaining data at the sample timing. For this reason, there is a problem that a high-speed and complicated signal processing circuit is required and power consumption increases.
[0007]
The present invention has been made in consideration of such circumstances, and the object thereof is to realize the IF processing and demodulation function of a receiver such as channel separation by digital signal processing and the number of AD conversion units and the digital signal. An object of the present invention is to provide a sampling device and a sampling method for simplifying a processing unit.
[0008]
[Means for Solving the Problems]
The present invention has been made to solve the above-described problems. When a system clock of another radio system is generated earlier than a preset priority system clock timing among a plurality of radio systems, a system clock obtained by thinning out the system clock of the other radio system and a system clock of the priority system Supply sampling clock with superimposed Timing control means;
And sampling means for sampling an added signal obtained by adding the received signals of the plurality of wireless systems by a sampling clock supplied by the timing control means.
[0009]
Further, the invention according to claim 2 is the invention according to claim 1, wherein the timing control means further includes the sampling means at a clock timing corresponding to each wireless system with respect to the plurality of wireless systems. Outputs an input trigger signal of the sampled data sampled.
[0011]
Claims 3 The invention described in claim 1 In the invention described in (1), when the system clock of the other wireless system is thinned, it further comprises data complementing means for complementing sampling data at the clock timing with sampling data before and after the clock timing.
[0012]
Claims 4 The invention described in When a system clock of another radio system is generated earlier than a preset priority system clock timing among a plurality of radio systems, a system clock obtained by decimating a system clock of the other radio system, and a priority system Sampling the added signal that is the sum of the received signals of the multiple wireless systems using the sampling clock superimposed on the system clock It is characterized by doing.
[0013]
Claims 5 The invention described in claim 4 The sampling data input trigger signal is further output to the plurality of radio systems at a clock timing corresponding to each radio system.
[0015]
Claims 6 The invention described in claim 4 When the system clock of the other wireless system is thinned out, the sampling data at the clock timing is further supplemented with sampling data before and after the clock timing for the plurality of wireless systems. Features.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a sampling apparatus of the present invention will be described with reference to the drawings. The sampling apparatus according to the present embodiment uses a method in which signals of a plurality of wireless systems are arranged on the frequency axis before the input of the AD converter and are collectively input to the AD converter. FIG. 1 is a configuration diagram showing a configuration of a wireless receiver to which the sampling device of this embodiment is applied.
The radio receiver according to the present embodiment includes RF / IF converter circuits 100-A and B of a plurality of radio systems A and B, IF circuits (demodulators) 101-A and B, and a sampling device 102. The
The RF / IF converter circuits 100-A and 100B perform processing such as low noise amplification, AGC amplification, and band limitation, respectively, and convert the RF signal (reception signal) into an IF signal. The two IF signals output from the RF / IF converter circuits 100-A and 100B are added by the adder 103 and input to the sampling device 102 as one IF signal (added signal).
The IF circuits (demodulators) 101-A and B receive the input of the IF signal that is AD-converted by the sampling device 102, demodulates it, and outputs it to an upper layer (communication control unit not shown).
[0017]
The sampling device 102 AD converts the addition signal input from the adder 103. Specifically, the sampling device 102 includes an AD conversion unit (sampler) 110, a timing control unit (A, B Timing Management) 111, and digital signal processing units 112-A and B.
The AD conversion unit 110 samples the addition signal (IF signal) obtained by adding the reception signals (RF signals) of the plurality of wireless systems A and B by the sampling clock (Sampling Clock (A + B)) supplied by the timing control unit 111. To do.
[0018]
The timing control unit 111 receives input of system clocks in the plurality of wireless systems A and B from the clock generators 120-A and B, and supplies a sampling clock in which the system clocks in the plurality of wireless systems A and B are superimposed. .
In addition, the timing control unit 111 outputs a sampling data input trigger signal (Timing trig.) Sampled by the AD conversion unit 110 at a clock timing corresponding to each of the wireless systems A and B as a digital signal. The data is output to the processing units 112-A and B.
In addition, the timing control unit 111 sets priorities for a plurality of wireless systems A and B from an upper layer (communication control unit). Based on the priority system selection signal (System Priority set (A or B)), the timing control unit 111 is earlier than the clock timing of the priority system set in advance among the plurality of wireless systems, and the system clock of the other wireless system When this occurs, a sampling clock in which the system clock obtained by thinning out the system clock of another wireless system and the system clock of the priority system are superimposed is supplied (described later).
The clock generation units 120-A and B supply a clock to the timing control unit 111 based on a timing control (System A, B timing adjustment) signal of an upper layer (communication control unit).
[0019]
The digital signal processing units 112-A, B are configured by data insertion units (Data Insertion) 121-A, B, digital filter processing units 122-A, B, and decimators 123-A, B.
When the timing control unit 111 thins out the system clock of another wireless system other than the priority wireless system, the data insertion units 121-A and 121-B perform the thinned clock based on the complementary trigger signal input from the timing control unit 111. The sampling data at the timing is calculated using the sampling data before and after the clock timing, and then complemented (described later).
The digital filter processing units 122-A and 122B perform necessary reception filter processing. Decimators 123-A and B perform necessary decimation processing (described later).
[0020]
Next, the operation of the wireless receiver to which the sampling device of this embodiment is applied will be described with reference to the drawings. FIG. 2 is a time chart showing a clock timing generation process in the timing control unit 111 of the present embodiment.
When the two IF signals output from the RF / IF converter circuits 100-A and 100B are added by the adder 103 and input to the sampling device 102 as one IF signal (added signal), AD conversion is performed. The unit 110 supplies a sampling clock in which a plurality of system clocks having timings corresponding to the wireless systems A and B are superimposed, and performs sampling processing at uneven timing.
[0021]
At this time, the timing control unit 111 adjusts the clock of one wireless system (for example, the wireless system A) to a priority timing and supplies the sampling clock. Specifically, when the clock of another wireless system (wireless system B) is generated earlier than the clock timing of the priority system (wireless system A), the clock is not generated, that is, the sampling process is temporarily omitted.
[0022]
This will be described with reference to FIG. In FIG. 2, the pulse width t of the clock waveform corresponding to each system is set to be the same as the maximum operation speed of the AD conversion unit 110.
The timing control unit 111 first detects that the system clock of another wireless system (wireless system B) is generated earlier than the clock timing of the priority system (wireless system A) based on the set priority.
That is, when a part of the system clock pulse (System A Clock) of the wireless system A in FIG. 2 overlaps the system clock pulse (System B Clock) of the wireless system B, the rising edge X portion (system of the wireless system A) When it is detected that the clock pulse) is delayed from the rising edge Y portion (system clock pulse of the wireless system B), a trigger signal (clocking edge P portion to falling edge P ′ portion indicating the clock timing for temporarily omitting the sampling process) However, the times of the rising edge P and the falling edge Y ′ correspond, and the times of the falling edge P ′ and rising edge X ′ correspond).
[0023]
Then, the timing control unit 111 generates a sampling clock in which the system clock obtained by thinning out the system clock of another wireless system (wireless system B) and the system clock of the priority system (wireless system A) are superimposed.
Specifically, a delayed clock signal (AT Clock, BT Clock) obtained by delaying the system clocks of the wireless systems A and B by one pulse is generated, and the delayed clock signal of the wireless system A and the wireless system are generated. The B delayed clock signal is added. Then, a signal obtained by subtracting the trigger signal from the added signal is generated and used as a sampling clock. The timing control unit 111 supplies this sampling clock to the AD conversion unit 110, and the AD conversion unit 110 performs sampling processing at non-uniform timing.
[0024]
In addition, the timing control unit 111 inputs sampling data sampled by the AD conversion unit 110 at a clock timing corresponding to each wireless system with respect to the data insertion units 121-A and B of the plurality of wireless systems A and B. A signal (Timing trig.) Is output. In addition, when the timing control unit 111 thins out the system clock of a wireless system other than the priority wireless system, the sampling data at the thinned clock timing is obtained before and after the clock timing based on the complementary trigger signal input from the timing control unit 111. Complement after calculating using sampling data.
[0025]
3 and 4 are configuration diagrams showing an embodiment of the data insertion units 121-A and B. FIG. As shown in FIG. 3, the data insertion units 121-A and 121B, when the complementary trigger signal of the input sampling data is input to the data selector 140 (Selector), the sampling data at the clock timing one sampling period before And an addition value obtained by adding the sampling data obtained by doubling the sampling data at the clock timing two sampling cycles before is selected as a complementary value.
Alternatively, as illustrated in FIG. 4, when the data insertion units 121 -A and 121 B are input to the data selector 140 after the complementary trigger signal of the input sampling data is delayed by one sampling period, one sampling is performed. The sampling data at the clock timing before the cycle and the sampling data at the clock timing after one sampling cycle are added together, and the sampling data multiplied by 1/2 is selected as a complementary value.
[0026]
Then, the digital signal processing units 112-A and 112B extract digital signals sampled at non-uniform timings at timings synchronized with the wireless systems A and B (clock timings corresponding to the respective systems) and perform digital signal processing. I do. Note that these processes correspond to usage patterns in which a priority system is arbitrarily switched to perform handover between wireless systems.
When receiving an IF signal after AD conversion from the digital signal processing units 112-A and 112B, the IF circuits (demodulators) 101-A and B demodulate the signals and output them to the upper layer.
[0027]
Therefore, according to the sampling apparatus of this embodiment of the present embodiment, a single AD conversion unit 110 can receive a plurality of wireless systems without using a signal processing unit such as the sampling rate converters 230-B and C. In addition, an effect of realizing a small-sized and power-saving wireless terminal can be obtained.
Moreover, according to the sampling apparatus of this embodiment of this embodiment, the effect that only the signal sequence required for each of the radio systems A and B can be processed is obtained.
Further, generation of clock timing exceeding the operable speed of the AD conversion unit 110 can be prevented, and deterioration of sampling performance can be prevented even when clock timing exceeding the operable speed is generated by superimposing the system clock. The effect that can be obtained.
Further, by complementing the sampling data, an effect of minimizing the performance degradation of the non-priority wireless system can be obtained.
[0028]
In the sampling device of this embodiment of the present embodiment, the relationship between the reception signal frequency and the sampling frequency is not particularly mentioned. For example, when determining the sampling frequency, the signal input to the AD conversion unit is In the case of the IF band, as shown in FIG. 5, the signal frequency and the sampling frequency may be selected to have a relationship of 1 / (4 × integer).
Specifically, as shown in FIG. 5, when there are two wireless systems to be received and the input signals are each in the IF signal band, the IF frequency is 3.84 MHz (wireless system B WCDMA). , 20 MHz (wireless system A WLAN), by selecting the sampling frequency to 61.44 MHz (wireless system B) and 80 MHz (wireless system A), the relationship between the signal frequency and the sampling frequency is 1 / (4 × integer) Set to.
[0029]
In the AD conversion unit 110, the input IF signal is sampled by a sampling clock in which two system clocks corresponding to the wireless systems A and B are superimposed, and converted into a digital signal.
Data insertion unit 121-A, B, BPF / LPF 122-A, B (corresponding to digital filter processing unit 121-A, B), digital down converter unit / IQ detection processing unit (DDC / IQDET) 124-A , B are digital signal processing units 112-A, B that operate on signals synchronized with the system clock of each wireless system. In the BPF / LPF 122-A, B, each of the two wireless systems A, B In addition to performing digital filter processing, the digital down-converter units 124-A and B perform frequency change processing. Then, IQ detection processing sections 124-A and 124B perform IQ detection processing to convert the baseband signal, and after decimation processing and reception filter processing, output.
[0030]
On the other hand, since the timing of each sampling clock is synchronized with the symbols of each system, information from the temperature compensation type crystal oscillator (TCXO: Temperature Compensated Crystal Oscillator), DDS (Direct Digital Synthesizer), and the demodulator ( System A (WLAN), System B (WCDMA),
Timing is adjusted by timing adjustment).
At this time, the clock generation units 120-A and 120B generate clocks whose two clock widths are delayed by the maximum operating frequency clock of the AD conversion unit 110 and the time t of the clock width. Generates a sampling clock of a signal composed of signals whose timings are independently adjusted in the clock generators 120-A and 120B.
[0031]
Then, the timing control unit 111 generates a system clock of another wireless system at a time earlier than the clock timing of the wireless system selected by the priority system selection signal, and prioritizes the wireless before the system clock returns to “0”. When the system clock of the system is generated, a complementary trigger signal is output to the data insertion units 121-A and B. In response to the complementary trigger signal, the data insertion units 121-A and 121B insert the sampling data obtained from the preceding and succeeding data at the clock timing where the sampling data does not exist.
With this configuration, it is possible to obtain an effect that simplifies the frequency conversion and IQ detection processing after the AD conversion unit.
[0032]
In addition, as an example of a receiver to which the sampling device according to the present embodiment of the present embodiment is applied, there are two wireless systems. However, the present invention is not limited to this, and as shown in FIG. It is also included in the present invention that there are three or more (wireless systems A to C), and that the input signals are baseband band IQ signals and IF signal band 2 signals, respectively.
In the case of the receiver configuration shown in FIG. 6, the baseband I signal and Q signal (BB IQ) output from one radio system A are output from radio system B (WCDMA) and radio system C (NCDMA), respectively. Are input to the two AD converters 103-1 and 103-2, respectively.
[0033]
That is, the adder 103-1 adds the I signal output from the RF / BB IQ conversion unit 100-A of the wireless system A and the IF signal output from the RF / IF conversion unit 100-B of the wireless system B. Is input to the AD converter 110-1.
Further, the adder 103-2 adds the Q signal output from the RF / BB IQ conversion unit 100-A of the wireless system A and the IF signal output from the RF / IF conversion unit 100-C of the wireless system C. Is input to the AD converter 110-2.
The addition signals output from the adders 103-1 and 103-2 are input to the AD conversion units 110-1 and 110-2, and non-uniform sampling processing is performed by a sampling clock (Sampling Clock A + B, A + C) supplied by the timing control unit 111. Done.
[0034]
The timing controller 111 supplies sampling clocks to the AD converters 103-1 and 103-2 based on the system clocks of the wireless systems A to C input from the clock generators 120-A to C. Sampling data is input to the digital signal processing units 112-AI, AQ (corresponding to the I signal and Q signal), B, and C.
In addition, the timing control unit 111 outputs a complementary trigger signal (Trig. AC) to the digital signal processing unit 112-AI, AQ, B, C data insertion unit 121-AI, AQ, B, C. .
As described above, the data insertion units 121-AI, AQ, B, and C supplement data with sampling data calculated based on preceding and following sampling data when a complement trigger signal is input.
In the digital signal processing unit 112-AI, AQ, B, and C, necessary filter processing, decimation processing, frequency conversion, and IQ detection processing are performed and output to the IF units of the wireless systems A to C.
[0035]
With this configuration, even in a receiver having three or more wireless systems, a plurality of AD conversion units 110-1 and 110-2 are used without using signal processing units such as sampling rate converters 230-B and 230C. In addition to enabling reception of the wireless system, it is possible to achieve an effect of realizing a small and power-saving wireless terminal.
Moreover, according to the sampling apparatus of this embodiment of this embodiment, the effect that only the signal sequence required for each of the radio systems A and B can be processed is obtained.
In addition, it is possible to prevent generation of clock timing exceeding the operable speed of the AD converters 110-1 and 110-2, and deterioration of sampling performance even when clock timing exceeding the operable speed occurs due to superposition of the system clock. The effect which can prevent is acquired.
Further, by complementing the sampling data, an effect of minimizing the performance degradation of the non-priority wireless system can be obtained.
[0036]
【The invention's effect】
As described above, the present invention samples the added signal obtained by adding the reception signals of the plurality of wireless systems by the sampling clock in which the system clocks in the plurality of wireless systems are superimposed. Therefore, the receiver IF processing such as channel separation is performed. In the case where the demodulation function is realized by digital signal processing, the number of AD conversion units and the digital signal processing unit can be simplified.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a wireless receiver when there are two wireless systems.
FIG. 2 is a time chart showing a clock timing generation process in a timing control unit.
FIG. 3 is a configuration diagram of a data insertion unit.
FIG. 4 is a configuration diagram of a data insertion unit.
FIG. 5 is a configuration diagram of a wireless receiver when there are two wireless systems.
FIG. 6 is a configuration diagram of a wireless receiver when there are three wireless systems.
FIG. 7 is a configuration diagram of a wireless receiver to which a conventional sampling device is applied.
[Explanation of symbols]
100-A to C, 200-A to C: RF / IF converter
101-A to B, 201-A to C ... IF unit
102, 202 ... Sampling device
103-1, 2, 203 ... Adder
110, 110-1, 2, 210 ... AD converter
111 ... Timing control unit
112-A (AI, AQ) to C: Digital signal processing unit
120-A to C, 211 ... Clock generator
121-A (AI, AQ) to C: Data insertion unit
122-A (AI, AQ) to C, 222-A to C: Digital filter processing unit (BPF, LPF)
123-A (AI, AQ) to C, 223-A ... Decimator
125-A (AI, AQ) to C: reception filter
140 ... selector
230-B, C ... Sampling rate converter

Claims (6)

When a system clock of another radio system is generated earlier than a preset priority system clock timing among a plurality of radio systems, a system clock obtained by thinning out the system clock of the other radio system and a system clock of the priority system Timing control means for supplying a sampling clock superimposed with
A sampling device comprising: sampling means for sampling an added signal obtained by adding the received signals of the plurality of wireless systems by a sampling clock supplied by the timing control means. The timing control means further includes:
The sampling apparatus according to claim 1, wherein an input trigger signal of sampling data sampled by the sampling unit is output to the plurality of radio systems at a clock timing corresponding to each radio system. The sampling according to claim 1 , further comprising data complementing means for complementing sampling data at the clock timing with sampling data before and after the clock timing when the system clock of the other radio system is thinned out. apparatus. When the system clock of another wireless system is generated earlier than the clock timing of the preset priority system among the plurality of wireless systems,
Furthermore, the addition signal obtained by adding the reception signals of the plurality of wireless systems is sampled by a sampling clock obtained by superimposing the system clock of the other wireless system and the system clock of the priority system. Sampling method. 5. The sampling method according to claim 4 , further comprising: outputting an input trigger signal of sampling data to the plurality of wireless systems at a clock timing corresponding to each wireless system. If thinning out the system clock of the other radio system, to the plurality of radio systems, further claim 4 sampling data in the clock timing, characterized in that complemented by the sampling data before and after of the clock timing The sampling method described in 1.

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