WO2017148224A1

WO2017148224A1 - Signal sampling method, device and system

Info

Publication number: WO2017148224A1
Application number: PCT/CN2017/071395
Authority: WO
Inventors: 周瑞兴; 乔朋; 吴广德
Original assignee: 中兴通讯股份有限公司
Priority date: 2016-03-01
Filing date: 2017-01-17
Publication date: 2017-09-08
Also published as: CN107147427A

Abstract

Disclosed are a signal sampling method, device and system. The method comprises: obtaining multiple useful signals having different frequencies by filtering received signals to be sampled, wherein the signals to be sampled are multiband broadband signals; shifting, by using a local oscillator signal corresponding to each useful signal, the multiple useful signals separately to different Nyquist intervals; combining multiple useful signals at different Nyquist intervals into one broadband signal; and sampling the combined broadband signals. By shifting multiple useful signals in signals to be sampled to different Nyquist intervals and further shifting, by means of frequency shifting, multiple broadband signals to different central frequency points, the present invention can not only ensure the performance of band signals, but also compress the bandwidth, thereby improving the bandwidth utilization and reducing circuit costs.

Description

Signal sampling method, device and system

Technical field

The present invention relates to the field of communications technologies, and in particular, to a signal sampling method, apparatus, and system.

Background technique

The development of wireless communication requires more spectrum resources and greater signal bandwidth to carry broadband services. However, due to the limited spectrum resources, broadband signals often need to be distributed over multiple discrete frequency bands. Traditional broadband multi-band receivers are usually implemented by using multiple channels. Such circuit structures are often complicated and difficult to achieve. Low cost and miniaturization. Figure 1 shows the circuit structure of a multi-channel receiver. Each channel of the multi-channel receiver independently processes signals of one frequency, has high selectivity, strong anti-interference ability, and good receiving performance, but the circuit scale is large, which is not conducive to miniaturization; the compatibility of various modes is poor; the circuit cost is high. .

With the development of Analog-to-Digital (AD) sampling technology, a wide-band analog-to-digital converter (ADC) can also be used for single-channel processing. The circuit structure of the single channel receiver is shown in Figure 2. The single-channel receiver uses one channel to process multi-band wideband signals, and the sampling clock frequency needs to be more than twice the starting frequency occupied by the broadband signals of multiple frequency bands.

Single-channel processing, multi-mode and multi-frequency compatibility is the future development direction of ultra-wideband receivers. However, the cost of single-channel processing increases geometrically with bandwidth, and performance is proportional to the AD sampling bandwidth. For example, the multi-band wideband signal includes n (n>1) wideband signals with discontinuous frequencies, and the center frequencies of the n wideband signals are respectively f ₁ , f ₂ , . . . , f _n , and the bandwidths of the n wideband signals respectively For bw1, bw2, ..., bwn, the start and stop frequency of the multi-band wideband signal occupies the bandwidth BW = (f _n + bwn / 2) - (f _{1 -} bw 1/2) = (f _n - f ₁ + (bwn + bw1) ) / 2), then, the sampling clock frequency Fs is required to satisfy Fs/2>f _n -f ₁ +(bwn+bw1)/2.

Therefore, the existing multi-band wideband signal sampling methods have the disadvantages of high cost and low performance.

Summary of the invention

The invention provides a signal sampling method, device and system, which are used to solve the problems of high cost and low performance of the sampling method of the existing multi-band broadband signal.

In response to the above technical problems, the present invention has been solved by the following technical solutions.

The present invention provides a method for sampling a signal, comprising: filtering out multiple useful signals of different frequencies in a received signal to be sampled; wherein the signal to be sampled is a multi-band wideband signal; utilizing each useful signal Corresponding local oscillator signals, respectively moving the multiple useful signals to different Nyquist intervals; combining multiple useful signals of different Nyquist intervals into one broadband signal; performing the combined broadband signals sampling.

The multi-channel useful signals of different frequencies are filtered out in the received signal to be sampled, including: dividing the signal to be sampled into multiple channels; and filtering the useful signals of different frequencies in the multiple signals to be sampled.

Wherein, using the local oscillator signal corresponding to each useful signal, respectively moving the multiple useful signals to different Nyquist intervals, including: using the local oscillator signal corresponding to each useful signal, The useful signals are moved to different Nyquist intervals of the same wideband analog-to-digital converter.

After the multiple useful signals are respectively moved to different Nyquist intervals, before combining the multiple useful signals of different Nyquist intervals into one broadband signal, the method further includes: separately for each The road is useful for anti-aliasing filtering.

The sampling the wideband signal obtained after the combining includes: sampling the combined wideband signal by using a preset sampling clock frequency; wherein the sampling clock frequency is greater than a sum of the bandwidths of the multiple useful signals Double.

The present invention provides a signal sampling device, comprising: a filtering module, configured to filter out multiple useful signals of different frequencies in the received signal to be sampled; wherein the signal to be sampled is a multi-band broadband signal; a module for moving the multiple useful signals to different Nyquist intervals by using a local oscillator signal corresponding to each useful signal; and combining modules for multiplexing multiple Nyquist intervals The signals are combined into one wideband signal; the sampling module is used to sample the combined wideband signals.

The filtering module is configured to: divide the signal to be sampled into multiple channels; and filter the useful signals of different frequencies in the multiple signals to be sampled.

The moving module is configured to: move the multiple useful signals to different Nyquist intervals of the same wideband analog-to-digital converter by using local oscillator signals corresponding to each useful signal.

The filtering module is further configured to: before moving the multiple useful signals to different Nyquist intervals, before combining the multiple useful signals of different Nyquist intervals into one broadband signal, Anti-aliasing filtering is performed on each useful signal separately.

The sampling module is configured to: sample the combined wideband signal by using a preset sampling clock frequency; wherein the sampling clock frequency is greater than twice the sum of the bandwidths of the multiple useful signals.

The invention provides a signal sampling system, comprising: a power divider, a frequency selective filter bank, a mixer group, an anti-aliasing filter bank, a combiner and a broadband digital-to-analog converter; The power splitter is configured to divide the received signal to be sampled into multiple channels; the signal to be sampled is a multi-band wideband signal; and the frequency selective filter bank is configured to separately perform signals in multiple signals to be sampled Filtering useful signals of different frequencies; the mixer group is configured to move the multiple useful signals to different Nyquist of the wideband analog-to-digital converter by using local oscillator signals corresponding to each useful signal The anti-aliasing filter bank is configured to respectively perform anti-aliasing filtering processing on each useful signal; the combiner is configured to combine multiple useful signals in different Nyquist intervals into one path Wideband signal; the wideband analog to digital converter for sampling the combined wideband signal.

Wherein the frequency selective filter bank includes a plurality of frequency selective filters, the mixer group includes a plurality of mixers, and the anti-aliasing filter bank includes a plurality of anti-aliasing filters; a splitter and the plurality of frequency selective filters respectively Connected; each frequency selective filter is connected to a mixer; each mixer is connected to an anti-aliasing filter; the plurality of anti-aliasing filters are respectively connected to the combiner; The plurality of signals to be sampled are respectively input to each of the frequency selection filters; each of the frequency selection filters is configured to filter the useful signal of the predetermined frequency in the input signal to be sampled, and filter the filtered The useful signals are output to the corresponding mixers; each of the mixers is configured to mix the input useful signals with the preset local oscillator signals, and output the mixed useful signals to corresponding anti-aliasing a stacking filter; each anti-aliasing filter is configured to perform anti-aliasing processing on the input useful signal, and output the anti-aliasing processed useful signal to the combiner; The useful signals respectively input by the plurality of anti-aliasing filters are combined into one broadband signal.

The wideband analog-to-digital converter is configured to sample the combined wideband signal by using a preset sampling clock frequency; wherein the sampling clock frequency is greater than twice the sum of the bandwidths of the multiple useful signals. .

The beneficial effects of the present invention are as follows:

The invention moves the multiple useful signals in the signal to be sampled to different Nyquist intervals, and then uses frequency shifting to move multiple broadband signals to different center frequency points, which can ensure the performance of the frequency band signal, and can also To the role of compression bandwidth, improve bandwidth utilization and reduce circuit cost.

DRAWINGS

1 is a schematic diagram showing the circuit structure of a conventional multi-channel receiver;

2 is a schematic circuit diagram of a conventional single channel receiver;

3 is a flow chart of a method of sampling a signal according to an embodiment of the present invention;

4 is a structural diagram of a signal sampling device according to an embodiment of the present invention;

FIG. 5 is a structural diagram of a signal sampling system according to an embodiment of the present invention; FIG.

6 is a detailed structural diagram of a signal sampling system according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of frequency shifting according to an embodiment of the invention; FIG.

FIG. 8 is a schematic diagram of frequency shifting according to another embodiment of the present invention; FIG.

FIG. 9 is a schematic structural diagram of a three-band receiver according to an embodiment of the present invention; FIG.

FIG. 10 is a schematic diagram of frequency shifting of a three-band signal according to an embodiment of the invention.

detailed description

The present invention distributes a plurality of discontinuous wideband signals through a spectrum, distributes them to different Nyquist zones of the same ADC, and samples a plurality of wideband signals sharing one ADC. The invention fully utilizes the bandwidth of the ADC, can also achieve the performance of the single-band signal, and simplifies the circuit structure and reduces the circuit cost; the sampling clock frequency of the ADC is more than twice the sum of the bandwidths of the multi-channel useful signals, so that the sampling bandwidth of the ADC can be reduced. Requirements to increase the utilization of ADC bandwidth and reduce circuit cost.

The invention will be further described in detail below with reference to the drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The present invention provides a method of sampling a signal, and FIG. 3 is a flow chart of a method of sampling a signal according to an embodiment of the present invention.

Step S310, filtering out multiple useful signals of different frequencies in the received signal to be sampled.

The signal to be sampled is a multi-band wideband signal. The multi-band wideband signal is an analog signal, and the multi-band wideband signal includes a multi-channel non-continuous wideband signal. The multi-channel wideband signal is transmitted by one or more senders. The wideband signal is a type of signal such as a voice signal, an image signal, or a data signal. Each wideband signal is referred to as a useful signal.

The frequency range of each wideband signal (useful signal) is known; the signal to be sampled is divided into multiple channels; and the useful signals of different frequencies are separately filtered in the multiple signals to be sampled. In other words, the discontinuous wideband signals of the multiple frequencies in the signal to be sampled are separately filtered out, and each wideband signal is used as a useful signal, and the frequency of each useful signal is different.

Step S320, the multi-channel useful signals are respectively moved (assigned) to different Nyquist intervals by using local oscillator signals corresponding to each useful signal.

According to the frequency range of each useful signal in the signal to be sampled, a corresponding local oscillator signal is set for each useful signal, and the frequency of the local oscillator signal corresponding to each useful signal is different, and each useful signal and the corresponding local oscillator signal are used. Mixing is performed by moving the useful signal to another frequency, thereby distributing the multiple useful signals to different Nyquist intervals.

Step S330, combining the multiple useful signals of different Nyquist intervals into one wideband signal.

In order to make full use of the bandwidth of the analog-to-digital converter and improve the performance of the single-band signal, the multi-channel useful signal can be separately moved to the different Nylon of the same wideband analog-to-digital converter by using the local oscillator signal corresponding to each useful signal. The sinter interval combines multiple useful signals of different Nyquist intervals in the same wideband analog-to-digital converter into one wideband signal.

Further, the multiplexed useful signals that are moved to different Nyquist intervals of the same wideband analog-to-digital converter can be mirrored in the first Nyquist interval of the wideband analog-to-digital converter, in order to suppress each useful signal Out-of-band spurs to prevent aliasing interference after moving the useful signal to each Nyquist zone, after moving the multiplexed useful signals to different Nyquist intervals, respectively, Before the multi-channel useful signals of the sinter interval are combined into one broadband signal, each of the useful signals can be separately subjected to anti-aliasing filtering.

In the wideband analog-to-digital converter, since the useful signal in the other Nyquist interval can be mirrored in the first Nyquist interval, the useful signal to be moved to the first Nyquist interval, And the images produced by other useful signals in the first Nyquist interval are combined into one wideband signal. The mirror image of the useful signal can be regarded as the useful signal, then the combined wideband signal contains multiple useful signals, and there is no aliasing between the useful signals.

Step S340, sampling the combined wideband signal.

Using the preset sampling clock frequency, the combined wideband signal is sampled; since the wideband signal obtained by combining the multiple useful signals is in the first Nyquist interval, the sampling clock frequency used for sampling is larger than the above The bandwidth of the useful signal is twice the sum of the bandwidth.

For example, the bandwidth of the multi-channel useful signal is bw1, bw2, ..., bwn, n>1, then the sampling clock frequency is Fs/2>bw1+bw2+...+bwn.

The wideband signal obtained after the combination is still an analog signal, and the analog signal is sampled, and the analog signal is quantized into a digital signal for subsequent digital signal processing on the digital signal.

The signal to be sampled according to the present invention includes multiple wideband signals (useful signals) of different frequencies, and the wideband signals of different frequencies in the signals to be sampled are split into circuits of different frequency bands for filtering. The invention utilizes frequency shifting to move multiple broadband signals to different central frequency points, which can play the role of compressing bandwidth, avoiding waste of sampling bandwidth, saving resources, reducing circuit cost, and simplifying circuit structure.

According to the present invention, two or more frequency bands can be sampled across a large wideband signal and shared by one ADC, and the sampling bandwidth of the ADC is smaller than the bandwidth of the signal to be sampled and the signal bandwidth interval. The benefit of this is that the ADC sampling bandwidth is reduced, the utilization of the ADC bandwidth is increased, and the circuit cost is reduced.

The present invention provides a signal sampling device. As shown in FIG. 4, it is a structural diagram of a sampling device for a signal according to an embodiment of the present invention.

The device includes:

The filtering module 410 is configured to filter out multiple useful signals of different frequencies in the signal to be sampled. The signal to be sampled is a multi-band wideband signal.

The moving module 420 is configured to move the multiple useful signals to different Nyquist intervals by using local oscillator signals corresponding to each useful signal.

The merging module 430 is configured to combine the multiple useful signals of different Nyquist intervals into one wideband signal.

The sampling module 440 is configured to sample the combined wideband signal.

In an embodiment, the filtering module 410 is configured to divide the signal to be sampled into multiple channels; and filter the useful signals of different frequencies in the multiple signals to be sampled.

In another embodiment, the shifting module 420 is configured to move the multiple useful signals to different Nyquist intervals of the same wideband analog-to-digital converter by using local oscillator signals corresponding to each useful signal. The merging module 430 combines the multiple useful signals for different Nyquist intervals of the same wideband analog-to-digital converter into one wideband signal.

In still another embodiment, the filtering module 410 is further configured to combine the multiple useful signals of different Nyquist intervals into one broadband after moving the multiple useful signals to different Nyquist intervals respectively. Before the signal, each of the useful signals is subjected to anti-aliasing filtering.

In still another embodiment, the sampling module 440 is configured to sample the combined wideband signal by using a preset sampling clock frequency; wherein the sampling clock frequency is greater than twice the sum of the bandwidths of the multiple useful signals. .

The functions of the device in this embodiment have been described in the method embodiment shown in FIG. 3, and therefore, in the description of the embodiment, the related description in the foregoing embodiment may be omitted. Narration.

The apparatus described in this embodiment can be applied to a signal receiver, which can be set at a base station Side, in order to sample the signal to be sampled (analog signal) received by the signal receiver on the base station side, thereby avoiding waste of sampling bandwidth and reducing circuit cost.

The present invention provides a sampling system for signals. FIG. 5 is a structural diagram of a signal sampling system according to an embodiment of the present invention.

The system includes a sequentially connected power splitter 510, a frequency selective filter bank 520, a mixer bank 530, an anti-aliasing filter bank 540, a combiner 550, and a wideband analog to digital converter 560.

The power splitter 510 is configured to divide the received signal to be sampled into multiple channels. The signal to be sampled is a multi-band wideband signal.

The frequency selective filter bank 520 is configured to filter the useful signals of different frequencies in the multiple signals to be sampled. Among them, the frequency of each useful signal is different. The frequency selective filter bank 520 can select a useful signal to suppress out-of-band signals.

The mixer group 530 is configured to move the multiple useful signals to different Nyquist intervals of the wideband analog-to-digital converter by using local oscillator signals corresponding to each useful signal. The frequency of the local oscillator signal corresponding to each useful signal is different.

The anti-aliasing filter bank 540 is configured to perform anti-aliasing filtering processing on each of the useful signals separately. The anti-aliasing filter bank 540 can suppress out-of-band spurs and avoid aliasing interference between useful signals placed in each Nyquist interval.

The combiner 550 is configured to combine the multiple useful signals of different Nyquist intervals into one wideband signal to feed the one wideband signal into the same wideband analog to digital converter.

A wideband analog to digital converter 560 is used to sample the combined wideband signals. Further, the wideband analog-to-digital converter is configured to sample the combined wideband signal by using a preset sampling clock frequency; wherein the sampling clock frequency is greater than twice the sum of the bandwidths of the multiple useful signals.

The frequency selective filter bank 520 includes a plurality of frequency selective filters, the mixer group 530 includes a plurality of mixers, and the anti-aliasing filter bank 540 includes a plurality of anti-aliasing filters. The number of frequency selective filters, the number of mixers, and the number of anti-aliasing filters are equal.

The power splitter 510 is respectively connected to a plurality of frequency selective filters; each of the frequency selective filters is connected with one mixer; each mixer is connected with an anti-aliasing filter; and the plurality of anti-aliasing filters are respectively connected Combiner 550.

Each frequency selective filter is responsible for filtering a useful signal of one frequency; the frequency of the local oscillator signal input to each mixer is different, and the mixer uses the local oscillator signal to shift the frequency of the useful signal of a certain frequency; Anti-aliasing filters are responsible for anti-aliasing of one frequency. The frequency selective filter, the mixer and the anti-aliasing filter are connected according to the respective responsible frequencies.

According to the above connection relationship, the power splitter 510, the frequency selective filter, the mixer, the anti-aliasing filter, the combiner 550, and the wideband analog-to-digital converter 560 perform the following processing on the sampled signal:

The power divider 510 inputs the plurality of signals to be sampled which are divided by the power into each of the frequency selection filters;

Each frequency selective filter is used to filter a useful signal of a predetermined frequency in the input signal to be sampled, and will filter The outputted useful signal is output to the corresponding mixer;

Each mixer is configured to mix the input useful signal with the preset local oscillator signal, and output the mixed useful signal to the corresponding anti-aliasing filter;

Each anti-aliasing filter is used to anti-alias the input useful signal, and output the anti-aliasing useful signal to the combiner 550;

The combiner 550 is configured to combine the useful signals respectively input by the plurality of anti-aliasing filters into one broadband signal, and input the combined broadband signals into the wideband analog-to-digital converter;

A wideband analog-to-digital converter (ADC) for sampling the wideband signal input by combiner 550.

In order to better illustrate the present invention, the processing of the signal of the present invention will be described in conjunction with the specific structural diagram of the sampling system of the signal shown in FIG.

The system includes a sequentially connected power splitter 510, a frequency selective filter bank 520, a mixer bank 530, an anti-aliasing filter bank 540, a combiner 550, a wideband analog to digital converter 560, and a baseband processing unit 570.

The frequency selective filter bank 520 includes a frequency selection filter FL1, a frequency selection filter FL2, ..., a frequency selection filter FLn, n>1.

The mixer group 530 includes a mixer Mixer_1, a mixer Mixer_2, ..., a mixer Mixer_n.

The anti-aliasing filter bank 540 includes an anti-aliasing filter IL1, an anti-aliasing filter IL2, ..., an anti-aliasing filter ILn.

Power splitter 510 to be sampled input signal, the signal to be sampled wideband signal comprises n groups, n sets of a wideband signal in accordance with the frequency ascending order, sets the center frequency of the wideband signal n are _{_{_{f 1, f 2 ...... f n}}} , (Unit: Hz); the bandwidth of the n sets of wideband signals are bw1, bw2, ... bwn, respectively (unit: Hz).

The start and stop frequencies of the n sets of wideband signals are respectively: (f _{1 -} bw 1/2) Hz - (f ₁ + bw 1/2) Hz, (f _{2 -} bw2 / 2) Hz - (f ₂ + bw2 / 2) Hz ,...,(f _n -bwn/2)Hz~(f _n +bwn/2)Hz;

The total bandwidth BW occupied by the n sets of wideband signals is: BW = (f _n + bwn / 2) - (f _{1 -} bw 1/2) = (f _n - f ₁ + (bwn + bw1) / 2).

FLl frequency selective filter, a mixer Mixer_1, IL1 anti-aliasing filter is connected to a path for processing a wideband signal center frequency f _1.

FL2 frequency selective filter, a mixer Mixer_2, IL2 an anti-aliasing filter is connected to a path for processing a wideband signal center frequency f _2.

So, FLn frequency selective filter, a mixer Mixer_n, ILn anti-aliasing filter is connected to a path for processing a center frequency f _n of the wideband signal.

The power splitter 510 divides the signal to be sampled into n paths and inputs them to the frequency selection filter FL1, the frequency selection filter FL2, ..., and the frequency selection filter FLn, respectively.

The frequency selective filter FL1, the frequency selective filter FL2, ..., and the frequency selective filter FLn respectively perform frequency selective filtering on the sampled signal. For example: select filter FL1 filter center frequency f ₁ of the wideband signal, frequency selective filter FL2 filter center frequency of the wideband signal f _2, ......, frequency selective filter FLn filter center frequency f _n of the wideband signal.

530 mixer set for frequency conversion, using the mixer local oscillator signal Mixer_1 LO_1, respectively, the center frequency f ₁ of the wideband signal to move an ADC560 first Nyquist zone, to obtain the center frequency f _'1 the wideband signal; Mixer_2 using the mixer local oscillator signal LO_2, the center frequency F _2, respectively, of a wideband signal to move ADC560 the second Nyquist zone, to obtain the center frequency f 'of the wideband signal _2; ...... The mixer Mixer_n uses the local oscillator signal Lo_n to move the wideband signal with the center frequency f _n to the nth Nyquist interval of the ADC 560 to obtain a wideband signal with a center frequency of f' _n , and then different frequencies. Wideband signals are distributed to different Nyquist intervals of the same ADC. Where f' ₁ = f _{1 -} Lo_1, f' ₂ = f _{2 -} Lo_2, f' _n = f _{n -} Lo_n.

Antialiasing filter IL1, IL2 is an anti-aliasing filter, ......, anti-aliasing filter ILn respectively the center frequency of f 'is _a wideband signal, the center frequency f' of the wideband signal _2, ......, center frequency anti is f _'n of the wideband signal aliasing filtering process to eliminate spurious band. To facilitate the design of anti-aliasing filter, so that each may be, but not limited to a single wideband signals in a Nyquist zone, and f _'1 is in the first Nyquist zone, f' ₂ ... in the second Nyquist zone ...f' _{n is} in the nth Nyquist zone.

Combiner 550 as the center frequency f 'is _a wideband signal, the center frequency f' of the wideband signal _2, ......, a center frequency f _'n-wideband signal into one, into the ADC560.

The ADC 560 quantizes the combined wideband signal samples into digital signals.

The baseband processing unit 570 performs digital signal processing on the digital signals.

FIG. 7 is a schematic diagram of frequency shifting according to an embodiment of the invention. As shown in FIG. 7, the signal to be sampled includes a wideband signal of two frequencies, namely carrier 1 and carrier 2, respectively, carrier 1 is moved to the first Nyquist of ADC 560, and carrier 2 is moved to the second of ADC 560. Nyquist interval. A mirror image of carrier 2 is included in the first Nyquist interval.

FIG. 8 is a schematic diagram of frequency shifting according to another embodiment of the present invention. As shown in FIG. 8, the signal to be sampled includes broadband signals of n frequencies, which are carrier 1, carrier 2, ..., carrier n, and carrier 1 is moved to the first Nyquist interval of ADC 560, and carrier 2 is Move to the second Nyquist interval of ADC 560, ..., move carrier n to the nth Nyquist interval of ADC 560. A mirror image of carrier 2, ..., carrier n is included in the first Nyquist interval.

It can be seen from FIG. 7 and FIG. 8 that the first Nyquist interval of the ADC 560 can form a complete signal to be sampled, thereby combining the wideband signals of different Nyquist intervals into one wideband signal. Thus, at the time of sampling, only the sampling clock frequency Fs/2>bw1+bw2+...+bwn is required, and distortionless sampling can be performed.

Existing Fs/2>f _n -f ₁ +(bwn+bw1)/2, the present invention only needs Fs/2>bw1+bw2+...+bwn, and f _n -f ₁ +(bwn+bw1)/2 Far greater than bw1+bw2+...+bwn. Therefore, the embodiment of the present invention can reduce the demand for the sampling bandwidth of the ADC, and the advantage of the present invention is more obvious when the frequency interval of the wideband signal is larger.

The invention utilizes the frequency shifting, Nyquist sampling law, can compress the bandwidth, avoid waste of sampling bandwidth and save resources.

The invention utilizes a mixer to move a plurality of broadband signals to different center frequency points, so that the broadband signals of the plurality of frequency points share one ADC, thereby reducing the circuit cost and simplifying the circuit structure.

The signal sampling system provided by the present invention can be applied to a three-band receiver of a Time Division Duplexing (TDD) Radio Remote Unit (RRU). The structure of the three-band receiver is shown in Figure 9.

TDD RRU is a 3G and 4G mixed-mode RRU. It has three working bands, which are:

1. A-band 15M bandwidth, frequency range 2010MHz ~ 2025MHz, mainly transmitting TD-SCDMA single-mode signals;

2, F band 30M bandwidth, frequency range 1885MHz ~ 1915MHz, the transmitted signal is LTE signal and TD-SCDMA mixed mode signal;

3, E-band 50M bandwidth, frequency range 2320MHz ~ 2370MHz, mainly transmitting LTE single-mode signals.

The signals including the F, A, and E frequency bands (the signals to be sampled) pass through the power divider of the three-band receiver, and are filtered by the frequency-selecting filters FL1, FL2, and FL3 of different frequency bands to respectively output the three frequency bands F, A, and E. signal of. The signal of the A band passes through the mixer Mixer_1, and the signal of the F band passes through the mixer Mixer_2, and the signal of the E band passes through the mixer Mixer_3.

The signals of the A, F, and E bands are frequency-converted in the mixers Mixer_1, Mixer_2, and Mixer_3, respectively. among them:

The frequency of the local oscillator signal Lo_1 corresponding to the A-band signal is 2122 MHz, which is a high local oscillator signal, and the frequency range of the A-band signal converted intermediate frequency signal A' is 97 MHz to 112 MHz, and the bandwidth is 15 MHz;

The frequency of the local oscillator signal Lo_2 corresponding to the F-band signal is 2122 MHz, which is a high local oscillator signal, and the frequency range of the intermediate frequency signal F' after the F-band signal conversion is 207 MHz to 237 MHz, and the bandwidth is 30 MHz;

The frequency of the local oscillator signal Lo_3 corresponding to the E-band signal is 2032 MHz, which is a low local oscillator signal, and the frequency range of the intermediate frequency signal E' after the E-band signal conversion is 288 MHz to 338 MHz, and the bandwidth is 50 MHz.

As shown in FIG. 10, the three intermediate frequency signals A, F, and E are sampled and moved to different Nyquist intervals, including the image of the E-band signal, the image of the F-band signal, and the A-band in the first Nyquist interval. The signal, and the image of the E-band signal, the image of the F-band signal, and the spectrum of the A-band signal are not aliased.

The sampling frequency of the ADC can be 245.76 MHz (245.76 > 2 * (15 + 30 + 50)), so embodiments of the present invention make full use of the bandwidth of the ADC.

Industrial applicability

The invention relates to the field of communication technology, which can not only ensure a frequency band by moving a plurality of useful signals in a signal to be sampled to different Nyquist intervals, and then using frequency shifting to move a plurality of broadband signals to different center frequency points. The performance of the signal can also play the role of compression bandwidth, improve bandwidth utilization, and reduce circuit cost.

While the preferred embodiments of the present invention have been disclosed for purposes of illustration, those skilled in the art will recognize that various modifications, additions and substitutions are possible, and the scope of the invention should not be limited to the embodiments described above.

Claims

A method of sampling a signal, comprising:

Filtering out multiple useful signals of different frequencies in the received signal to be sampled; wherein the signal to be sampled is a multi-band wideband signal;

Using the local oscillator signal corresponding to each useful signal, the multiple useful signals are respectively moved to different Nyquist intervals;

Combining multiple useful signals in different Nyquist intervals into one wideband signal;

The wideband signals obtained after the combination are sampled.
The method of claim 1 wherein filtering the plurality of useful signals of different frequencies in the received signal to be sampled comprises:

Dividing the signal to be sampled into multiple channels;

The useful signals of different frequencies are separately filtered in the multiple signals to be sampled.
The method of claim 1 wherein the plurality of useful signals are separately moved to different Nyquist intervals using local oscillator signals corresponding to each of the useful signals, including:

The multi-channel useful signals are respectively moved to different Nyquist intervals of the same wideband analog-to-digital converter by using local oscillator signals corresponding to each of the useful signals.
The method of claim 1 wherein after multiplexing the plurality of useful signals to different Nyquist intervals, before combining the multiple useful signals of different Nyquist intervals into one wideband signal The method further includes:

Anti-aliasing filtering is performed on each useful signal separately.
The method of any of claims 1-4, wherein sampling the combined wideband signals comprises:

Using the preset sampling clock frequency to sample the combined wideband signal;

The sampling clock frequency is greater than twice the sum of the bandwidths of the multiple useful signals.
A signal sampling device comprising:

a filtering module, configured to filter out multiple useful signals of different frequencies in the received signal to be sampled; wherein the signal to be sampled is a multi-band wideband signal;

The moving module is configured to use the local oscillator signal corresponding to each useful signal to move the multiple useful signals to different Nyquist intervals respectively;

a merging module configured to combine multiple useful signals of different Nyquist intervals into one wideband signal;

The sampling module is configured to sample the combined wideband signal.
The apparatus of claim 6 wherein said filtering module is configured to:

Dividing the signal to be sampled into multiple channels;

The useful signals of different frequencies are separately filtered in the multiple signals to be sampled.
The apparatus of claim 6 wherein said moving module is configured to:

The multi-channel useful signals are respectively moved to different Nyquist intervals of the same wideband analog-to-digital converter by using local oscillator signals corresponding to each of the useful signals.
The apparatus of claim 6 wherein said filtering module is further configured to:

After moving the multiple useful signals to different Nyquist intervals, respectively, anti-aliasing each useful signal before combining the multiple useful signals of different Nyquist intervals into one broadband signal Filter processing.
The apparatus of any of claims 6-9, wherein the sampling module is configured to:

Using the preset sampling clock frequency to sample the combined wideband signal;

The sampling clock frequency is greater than twice the sum of the bandwidths of the multiple useful signals.
A signal sampling system comprising:

a sequentially connected power divider, a frequency selective filter bank, a mixer group, an anti-aliasing filter bank, a combiner, and a wideband digital-to-analog converter;

The power splitter is configured to divide the received signal to be sampled into multiple channels; the signal to be sampled is a multi-band wideband signal;

The frequency selective filter bank is configured to separately filter useful signals of different frequencies in the multiple signals to be sampled;

The mixer group is configured to move the multiple useful signals to different Nyquist intervals of the wideband analog-to-digital converter by using local oscillator signals corresponding to each useful signal;

The anti-aliasing filter bank is configured to perform anti-aliasing filtering processing on each useful signal separately;

The combiner is configured to combine multiple useful signals of different Nyquist intervals into one broadband signal;

The wideband analog to digital converter is configured to sample the combined wideband signal.
The system of claim 11 wherein

The frequency selective filter bank includes a plurality of frequency selective filters, the mixer group includes a plurality of mixers, and the anti-aliasing filter bank includes a plurality of anti-aliasing filters;

The power splitter is respectively connected to the plurality of frequency selective filters; each frequency selective filter is connected to a mixer; each mixer is connected with an anti-aliasing filter; the plurality of anti-aliasing Stacking filters are respectively connected to the combiner;

The power divider inputs the plurality of signals to be sampled which are divided by the power into each of the frequency selection filters;

Each frequency selective filter is configured to filter a useful signal of a predetermined frequency in the input signal to be sampled, and output the filtered useful signal to a corresponding mixer;

Each mixer is configured to mix the input useful signal with a preset local oscillator signal, and output the mixed useful signal to a corresponding anti-aliasing filter;

Each anti-aliasing filter is configured to perform anti-aliasing processing on the input useful signal, and output the anti-aliasing processed useful signal to the combiner;

The combiner is configured to combine the useful signals input by the plurality of the anti-aliasing filters into one broadband signal.
A system according to claim 11 or 12, wherein

The wideband analog-to-digital converter is configured to sample the combined wideband signal by using a preset sampling clock frequency;

The sampling clock frequency is greater than twice the sum of the bandwidths of the multiple useful signals.