CN102495824B - Method for generating multi-channel analog signals with different frequencies on same analog output card - Google Patents
Method for generating multi-channel analog signals with different frequencies on same analog output card Download PDFInfo
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- CN102495824B CN102495824B CN201110362379.7A CN201110362379A CN102495824B CN 102495824 B CN102495824 B CN 102495824B CN 201110362379 A CN201110362379 A CN 201110362379A CN 102495824 B CN102495824 B CN 102495824B
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Abstract
The invention discloses a method for generating multi-channel analog signals with different frequencies on the same analog output card. The method includes creating a two-dimensional array used for storing sampled data of the multi-channel analog signals which are required to be outputted by the analog output card and have different frequencies; determining a sampling frequency when the analog output card works; and reading the data of the two-dimensional array by the analog output card according to a sampling period, realizing digital/analog conversion for the read data, and generating a waveform. The method is successfully applied to satellite attitude control test equipment, practices prove that the method is reliable and improved, the frequencies of the outputted signals are stable, the phase relationship among the signals is strictly synchronous, parameters of the signals can be dynamically adjusted, and performances can completely meet index requirements of the test equipment.
Description
Technical field
The present invention relates to the generation of simulating signal, particularly a kind of method adopting one piece of analog output card to produce multichannel different frequency simulating signal.
Background technology
In satellite test process, need ground checkout equipment to provide the signal of different wave to satellite by test needs simultaneously, during for analog satellite in orbit, attitude sensor or other device measurings are to attitude signal, detectable signal, and then test the function of attitude measurement system, information handling system on star.The precision of general attitude of satellite sensor is all higher (signal accuracy is at about 0.01 degree), higher to having the frequency stability of strict phase requirements, signal to require between the precision of the signal of broadcasting TV programs by satellite and signal, and the frequency of desired signal is various, the parameter such as amplitude, frequency of signal will need dynamically to change according to test in test process.Before the present invention's application, when needs produce multiple signals, usually can adopt following several implementation:
1, by the oscillatory circuit of the forms such as simulation RC, RLC, LC, with the use of operational amplifier, active or passive filter circuit generation simulating signal;
2, pulse signal is produced by multivibrator, crystal oscillator isopulse signal generator, the pulse signal of certain dutycycle and frequency is produced again, then by producing simulating signal after operational amplifier, active or passive filter circuit, digital filter circuit filtering by counter frequency division;
3, pulse signal is produced by multivibrator, crystal oscillator etc., the pulse signal of fixed frequency is produced again by counter frequency division, first quantize needing the simulating signal generated, then be stored in rom chip, CPU is adopted to control the signal be stored in ROM to be changed by D/A again, the final simulating signal generated.
4, by the PXI/PCI analog output card (A0 card) of standard, call Labcard driver Control card by establishment board control program and generate required simulating signal, when needs generate different frequency signals, need configuration polylith analog output card, a kind of corresponding board of signal of frequency.
In above scheme, 1 scheme is only suitable for generating the relatively simple waveform such as sine wave, triangular wave, trapezoidal wave, for the output of the simulating signal of complexity, helpless, and lower by the precision of the waveform of program generation, being subject to external environment condition interference, can there is drift in signal parameter in time.2 schemes are mainly used in production burst signal simple signal relative to other, can there is the defect of 1 scheme too.3 schemes can realize the output of complicated multichannel analog signals, but need oneself exploitation board or circuit, and due to waveform data point need solidify in ROM, dynamically cannot change the parameter of waveform, the generation for the generation of complicated wave form, required D/A conversion sampling number certificate is also more difficult; For different index request, need to develop different circuits, poor universality; Oneself exploitation circuit, need experience, circuit debugging also very loaded down with trivial details, reliability design is poor.4 schemes are compared 3 scheme versatilities and are improved, and without oneself design circuit, debug circuit, owing to being industrial matured product, all having carried out strict test before dispatching from the factory, reliability is high; But the sample frequency of each passage is identical, only relies on board hardware resource cannot obtain multi-frequency simulating signal, need polylith board could produce the signal of different frequency.
Summary of the invention
The object of the invention is to overcome same analog output card in prior art and can only export a kind of defect of simulating signal of frequency, thus a kind of method exporting multi-frequency simulating signal on same analog output card is provided.
To achieve these goals, the invention provides a kind of method producing multichannel different frequency simulating signal on same analog output card, comprising:
Step 1), create one for preserving the two-dimensional array of the sampled data of the simulating signal of the multichannel different frequency that described analog output card will export; The columns of described two-dimensional array illustrates the way of described multiple signals, and each column data of described two-dimensional array illustrates the waveform of corresponding road signal, and in described two-dimensional array, every data line represents the output voltage values of synchronization;
Step 2), determine described analog output card sample frequency operationally;
Step 3), described analog output card reads data by the sampling period from described two-dimensional array, and does D/A switch to read data, generates waveform; Wherein, this step comprises:
Step 3-1), when reading data from described two-dimensional array, reading size according to the sampling period corresponding to the signal that described multichannel analog signals medium frequency is the highest from each row of described two-dimensional array is the data of n;
Step 3-2), size of data in described 2-D data is N and N is greater than the row of n, N-n data last in these row are taken out and are given buffer memory;
Step 3-3), fill into data for described 2-D data; Wherein, size of data is N and N is greater than the row of n, when the value of described N-n is more than or equal to n, using the new data of this N-n data as these row, when the value of described N-n is less than n, after described last N-n data, fill into complete N number of data, it can be used as the new data of these row;
Step 3-4), re-execute step 3-1), until meet end condition.
In technique scheme, described step 1) comprising:
Step 1-1), according in the maximum sampling rate index of analog output card and the highest frequency determination two-dimensional array of required generation analog output signal for representing the data bulk upper limit of a certain row of frequency most Gao mono-tunnel output signal:
S in above formula
maxfor the maximum sampling rate that described analog output card has, f
maxfor the highest frequency of required generation signal, n
maxfor the maximum number of the data point that analog output card can produce;
Step 1-2), according to step 1-1) established data transformation and signal accuracy determine the quantity n of a certain column data in described two-dimensional array
s;
Step 1-3), according to the ratio between the signal of different frequency and step 1-2) in determine the quantity of a certain column data to confirm the quantity of other column datas.
The invention has the advantages that:
1, the present invention achieves the output of multichannel different frequency high-precision analog signal on one piece of analog output card, solves the function that prior art needs polylith board to realize, reduces and realize cost, improve the net synchronization capability between signal.
2, after adopting method of the present invention, the simulating signal that different passage exports is when frequency is identical or differ integral multiple, and the phase differential between its signal remains constant, namely meets phase-locking; The simulating signal that different passage exports, when frequency is different or when differing non-integral multiple, the initial phase difference of signal in one-period is identical, namely meets initial phase synchronous.
Accompanying drawing explanation
Fig. 1 is the program flow diagram of the inventive method.
Fig. 2, to generate 3 tunnel simulating signals, shows and generates the mapping situation of multichannel same frequency signal original sampling data point two-dimensional array data in calculator memory.
Fig. 3 is to generate 2 road f
1frequency and 1 road f
2frequency signal is example, when showing generation multichannel different frequency signals, at first f
1signal period, two-dimensional array data-mapping form in calculator memory of its original sampling data point composition.
Fig. 4, on the basis of step shown in Fig. 3, shows at second f
1signal period, at computing machine by first f
1the array data of signal period is sent to PXI or PCI analog output card and is carried out D/A conversion, when generating waveform, by first f
1the schematic diagram of the taking-up from the 3rd row of last N-n data point, buffer memory in 3rd sequence in signal period.
Fig. 5 is on the basis operated shown in Fig. 4, and how show is the schematic diagram of two-dimensional array supplementary data.
Fig. 6 on the basis operated shown in Fig. 5, at generation the 3rd f
1signal period, when sample data be admitted to D/A change time, remaining data 2 (N-n) data of the 3rd row new in operation shown in Fig. 5 to be taken out from the 3rd row, the schematic diagram of buffer memory.
Fig. 7 is on the basis operated shown in Fig. 6, and how show is the schematic diagram of two-dimensional array supplementary data.
Fig. 8 shows at generation K f
1signal period, when sample data be admitted to D/A change time, remaining data k (N-n) data of the 3rd row new in the operation of k-1 step to be taken out from the 3rd row, the schematic diagram of buffer memory.
Fig. 9 is on the basis operated shown in Fig. 8, and how show is the schematic diagram of two-dimensional array supplementary data.
Embodiment
Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described.
Before method of the present invention is elaborated, first the hardware involved by the inventive method is described.
Realize method of the present invention and need computing machine, analog output card, described analog output card includes a plate and carries FIFO buffer, and this buffer supports DMA transmission mode.Described analog output card has multiple output channel, and these output channels have D/A translation function, can be used for multiple signals being converted to analog format by digital format and exporting.Analog output card includes standard P XI (or PCI) bus interface, to realize the communication between described computing machine.Described PXI (or PCI) bus interface is a kind of industrial standard computer bus specification of Based PC, and its highway width is 32, operating voltage 3.3V/5.5V, and frequency is 66MHz/132MHz.
Just as mentioned in the background, generally speaking, each output channel in an analog output card has identical sample frequency, therefore, one or more signal of same frequency can only be exported at one time, can not export the multiple signals of different frequency, otherwise the integrality of the signal exported can be affected.This just makes just to need multiple analog output card to export multi-frequency simulating signal in prior art.
With reference to figure 1, the present invention achieves the simulating signal at same analog output card output multi-channel different frequency through the following steps.
Step 1), create a two-dimensional array, for preserving the sampled data of the multichannel analog signals that analog output card will export.
In this step, the columns of the two-dimensional array that create illustrates the way needing the signal produced, and each column data of two-dimensional array illustrates the waveform of this road signal, and in two-dimensional array, every data line represents the output voltage values of synchronization.The schematic diagram of described two-dimensional array is sets forth in Fig. 2, Fig. 3.
This step comprises following sub-step:
Step 1-1), first according in the maximum sampling rate index of analog output card and the highest frequency determination two-dimensional array of required generation signal for representing the data bulk upper limit of a certain row of frequency most Gao mono-tunnel output signal, namely the maximum data point calculating method on a certain road is:
S in above formula
maxfor the maximum sampling rate that analog output card has, f
maxfor the highest frequency of required generation signal, n
maxfor the maximum number of the data point that analog output card can produce.
Step 1-2), according to upper step established data transformation, consider the quantity of a certain column data in desired signal precision determination two-dimensional array, generally can select that the maximum data obtained in previous step is counted 70% ~ 80%, be taken as 75% herein.Namely
n
s＝75％n
max
For same frequency signal, the sampled data of each road signal is counted and is all determined according to above formula, and the number of data points for other frequency signals needs to determine according to the following formula:
N in above formula
sfor the number of data points required for other frequency signals, all different for the sampling number needed for different frequency signals, be designated as N
s1, N
s2... N
sn; f
1represent above-mentioned highest frequency, f
2represent other frequencies.
For Fig. 2, in the embodiment represented by this figure, have three road homogenous frequency signals, the data volume in the one-dimension array array I, the array II that represent three road homogenous frequency signals respectively that therefore obtain according to above-mentioned steps, array III is identical, can represent with n; And in the embodiment represented by Fig. 3, Ye You tri-road signal, but the frequency of the 3rd road signal is different from first, second road signal, therefore, the data volume of array I, array II is identical, all represents with n, and the data volume of array III represents with N, N > n.
In the buffer memory that the two-dimensional array that this step is formed can be kept at computing machine or internal memory.
Step 2), determine when analog output card works sample frequency.
According to data volume and the required generation signal frequency of the signal data array determined, determine sample frequency when analog output card works.Computing method are as follows:
f
s＝n
sf
signal
F in above formula
sfor sample frequency when analog output card works, n
sfor the data bulk of the one-dimension array of reality, f
signalfor required generation signal frequency.Mention, if there is the simulating signal of different frequency in multichannel analog signals, the data bulk of so actual one-dimension array can be different before, as shown in Figure 3, in the case, and described n
sthe data volume size of the one-dimension array that quantity of fetching data is minimum.As shown in Figure 3, N > n, therefore n
svalue be n.If there is the simulating signal of different frequency in multichannel analog signals, so f
signalfrequency corresponding to the signal that multichannel analog signals medium frequency is the highest.
Step 3), analog output card reads data by the cycle from described two-dimensional array, read data are done D/A conversion, generate waveform.
When the signal frequency that will export is identical, by the cycle by step 1) data in the two-dimensional array corresponding with all signals that create are transferred to the respective channel of described analog output card, and complete D/A conversion, generate waveform.This type of situation solves in the prior art, is not the scope that the present invention will discuss, does not therefore elaborate herein.
Emphasis is just when the signal that will export has multiple frequency below, and how analog output card is described by the process of cycle reading data.
In one embodiment, for Fig. 3, the simulating signal that export has three tunnels, and wherein two-way is f
1frequency signal, an other road is f
2frequency signal.According to step before, at first f
1signal period, as shown in Figure 3, in this two-dimensional array the 1st, 2 sequences are f to the two-dimensional array that its original sampling data point is formed
1frequency signal sample points certificate, altogether n data; 3rd sequence is f
2frequency signal sample points certificate, altogether N number of data.
At second f
1signal period, computing machine is by first f
1the array data of signal period is sent to analog output card and is carried out D/A conversion, generates waveform.In the process of transmission, the data volume that size is n is all transmitted for each row in two-dimensional array, therefore as shown in Figure 4, needs first f
1in signal period, in the 3rd sequence, last N-n data point is taken out and buffer memory from the 3rd row., as shown in Figure 5, then fill into new data for described two-dimensional array then.For the first via, the second road signal, owing to all data in array I, array II all being read before, as long as therefore by newly-generated data cover legacy data.But for the 3rd road signal, a buffer memory last N-n data point, now needing to judge whether N-n is less than n, as being less than, filling into N number of sample number strong point corresponding to the 3rd complete road signal thereafter before, forming the new sequence that a new length is 2N-n, is then f by this row new data and frequency
1two column datas of signal merge, form a new two-dimensional array, from this two-dimensional array, takes out the front capable data of n send analog output card to carry out D/A conversion.If N-n the data bulk taken out is more than or equal to n, then do not filling into N number of sample point thereafter, directly its first two columns with array is formed new two-dimensional array, same, from this two-dimensional array, the front capable data of n of taking-up send analog output card to carry out D/A conversion.
3rd f
1signal period, the sample data be kept in two-dimensional array continues to be transferred to analog output card, as shown in Figure 6, needs remaining 2 (N-n) data of the 3rd row new in Fig. 5 to take out and buffer memory from the 3rd row.Then continue as described two-dimensional array and supplement new data.As shown in Figure 7, when for the 3rd row supplementary data, whether the data length that will take out the remaining data 2 (N-n) of also buffer memory before from the 3rd row is less than n judges, if be less than, then filling into N number of sample number strong point corresponding to the 3rd complete road signal thereafter, form the new sequence that a new length is 3N-2n, then by this row new data and f
1two column datas of signal merge, and forms a new two-dimensional array, take out the front capable data of n and send analog output card to carry out D/A conversion from this two-dimensional array.If 2 (N-n) the individual data bulk taken out is greater than n, then do not filling into N number of sample point thereafter, directly itself and the first two columns of array are formed new two-dimensional array, same, from this two-dimensional array, take out the front capable data of n send analog output card to carry out D/A conversion.
At K f
1signal period, as shown in Figure 8, when sample data be admitted to D/A change time, remaining data k (N-n) data of the 3rd row new in the operation of k-1 step are taken out and buffer memory from the 3rd row.Then, continue as described two-dimensional array and supplement new data.As shown in Figure 9, when for the 3rd row supplementary data, judge whether remaining data k (N-n) is less than n, as being less than, filling into N number of sample number strong point corresponding to the 3rd complete road signal thereafter, form the new sequence that a new length is KN-(k-1) n, then by this row new data and f
1two column datas of signal merge, and forms a new two-dimensional array, take out the front capable data of n and send analog output card to carry out D/A conversion from this two-dimensional array.If k (N-n) the individual data bulk taken out is greater than n, then do not filling into N number of sample point thereafter, directly itself and the first two columns of array are formed new two-dimensional array, same, from this two-dimensional array, take out the front capable data of n send analog output card to carry out D/A conversion.
Repeat renewal reconstruct and the D/A conversion of above array data, continuously can export the simulating signal of different frequency.
In the above-described embodiments, the implementation procedure of the inventive method is described.Although in the above-described embodiments, multichannel analog signals only has two kinds of frequency values, and in other embodiments, if there is the output signal of more kinds of frequency, reference is f to frequency
2the processing procedure of signal, also can realize the output of the simulating signal to corresponding frequencies.
Method of the present invention Successful utilization in Fengyun II meteorological satellite posture control system ground checkout equipment.This equipment achieves the generation of 8 tunnel attitude pumping signals by monolithic NI company PXI-6733 analog output card, wherein has two paths of signals frequency to be 0.54 times of other 6 tunnel signal frequencies.8 tunnel output signal accuracy are all better than index request, phase-locking between 6 road homogenous frequency signals, another 2 road homogenous frequency signals (0.54 times for another 6 tunnel signal frequencies) phase-locking, and between 8 road signals after device start initial phase synchronous.This equipment is tested and expert's Acceptance Review by inspection, and drop into real satellite test more than a year, applicable cases is good, and output signal meets Fengyun-II satellite posture control system test request completely.
Claims (1)
1. on same analog output card, produce a method for multichannel different frequency simulating signal, comprising:
Step 1), create one for preserving the two-dimensional array of the sampled data of the simulating signal of the multichannel different frequency that described analog output card will export; The columns of described two-dimensional array illustrates the way of the simulating signal of described multichannel different frequency, and each column data of described two-dimensional array illustrates the waveform of corresponding road signal, and in described two-dimensional array, every data line represents the output voltage values of synchronization;
Described step 1) comprising:
Step 1-1), according in the maximum sampling rate index of analog output card and the highest frequency determination two-dimensional array of required generation analog output signal for representing the data bulk upper limit of a certain row of frequency most Gao mono-tunnel output signal:
S in above formula
maxfor the maximum sampling rate that described analog output card has, f
maxfor the highest frequency of required generation signal, n
maxfor the maximum number of the data point that analog output card can produce;
Step 1-2), according to step 1-1) established data transformation and signal accuracy determine the quantity n of a certain column data in described two-dimensional array
s;
Step 1-3), according to the ratio between the signal of different frequency and step 1-2) in determine the quantity of a certain column data to confirm the quantity of other column datas;
Step 2), according to the data volume of the signal data array determined and required generation signal frequency, determine sample frequency when described analog output card works;
Step 3), described analog output card reads data by the sampling period from described two-dimensional array, and does D/A switch to read data, generates waveform; Wherein, this step comprises:
Step 3-1), when reading data from described two-dimensional array, reading size according to the sampling period corresponding to the signal that described multichannel analog signals medium frequency is the highest from each row of described two-dimensional array is the data of n, wherein, works as n
sduring the data volume size of the array that quantity of fetching data is minimum, n=n
s, i.e. the data bulk of the array of n corresponding to the highest output signal of multichannel analog signals medium frequency;
Step 3-2), size of data in described 2-D data is N and N is greater than the row of n, N-n data last in these row are taken out and given buffer memory, wherein, N in multichannel analog signals except the output signal of highest frequency other frequencies output signal corresponding to the data bulk of array;
Step 3-3), fill into data for described 2-D data; Wherein, size of data is N and N is greater than the row of n, when the value of described N-n is more than or equal to n, using the new data of this N-n data as these row, when the value of described N-n is less than n, after described last N-n data, fill into complete N number of data, it can be used as the new data of these row;
Step 3-4), re-execute step 3-1), until meet end condition.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5463467A (en) * | 1993-06-29 | 1995-10-31 | Boehringer Mannheim Gmbh | Light source pulsed with irregular pulse sequence in analog photometric signal evaluation for a test carrier analysis system |
| CN101389978A (en) * | 2005-07-28 | 2009-03-18 | 卡尔斯特里姆保健公司 | Low noise image data capture for digital radiography |
| CN101477376B (en) * | 2009-01-14 | 2010-09-08 | 南京航空航天大学 | Fault injection method for spacecraft actuating mechanism |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5463467A (en) * | 1993-06-29 | 1995-10-31 | Boehringer Mannheim Gmbh | Light source pulsed with irregular pulse sequence in analog photometric signal evaluation for a test carrier analysis system |
| CN101389978A (en) * | 2005-07-28 | 2009-03-18 | 卡尔斯特里姆保健公司 | Low noise image data capture for digital radiography |
| CN101477376B (en) * | 2009-01-14 | 2010-09-08 | 南京航空航天大学 | Fault injection method for spacecraft actuating mechanism |
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