CN101059708A - Digital angle converter implementation method - Google Patents

Abstract

The invention relates to a method for realizing a digit angle converter circuit, composed of a photoelectric coupler, two DA converters, a sine multiplier, a cosine multiplier, a voltage boost and drive circuit, a sine wave generator, an angle and analogue digit amount convert control circuit, and an angle data register. The angle and analogue digit amount convert control circuit detects the data change of the data register, to calculate out the digit amounts relative to Sin(theta) and Cos(theta) according to the angle amount theta of new data when the angle data register is written with new data, the two DA converts convert the Sin(theta) and Cos(theta) digit amounts to relative analogue amounts, to be multiplied with a reference signal, and automatically recognize the input data signal after conversation, to repeat aforementioned process. The invention uses general elements to realize the function and main technical indexes of DRC chip, with reduced cost.

Description

A kind of implementation method of digital angle converter

Technical field

The invention belongs to the Computer Applied Technology field, be specifically related to the implementation method of digital angle converter (DRC).

Background technology

For many years, the realization of DRC converter all is to adopt special-purpose DRC chip to realize.DRC chip commonly used has AD2S65/66, the DRC1745/1746 etc. of U.S. AD company.

These chips all are the hybrid package circuit, cost an arm and a leg and are limited by external.About 1999, because the stopping production of DRC chip, cause (being difficult to buy) in short supply of the source of goods and raise up (13450 yuan of every agreements that contracts a film or TV play to an actor or actress) of price, make original design integrated circuit board not use, have to change the device otherwise designed, or just need to wait for very long procurement cycle and will unilaterally accept expensive unit price.

Summary of the invention

The objective of the invention is to, a kind of implementation method of digital angle converter is provided, the inconvenience that brings with the stopping production that remedies the DRC chip, and reduce the high cost of DRC chip significantly.

In order to realize above-mentioned task, the present invention takes following technical solution:

A kind of implementation method of digital angle converter is characterized in that, comprises the following steps:

The first step is at first determined circuit structure, and its structure comprises:

By photoelectrical coupler control system and analog angle signal are isolated, be connected with a DA converter and the 2nd DA converter on this photoelectrical coupler respectively, the one DA converter is connected with sinusoidal multiplier, the 2nd DA converter is connected with the cosine multiplier, sinusoidal multiplier and cosine multiplier are connected with sinusoidal voltage lifting and driving circuit and cosine voltage respectively and promote and driving circuit, and be connected with on sinusoidal multiplier and the cosine multiplier as sine-wave generator, also have the voltage of reference signal to promote and driving circuit on the sine-wave generator with reference to signal.

Photoelectrical coupler also is connected with an angle and analog digital amount conversion control circuit, by angle and analog digital amount conversion control circuit the angular metric θ that imports is calculated conversion, be connected with the angle-data register on angle and the analog digital amount conversion control circuit.

In second step, determine the circuit working flow process.The data variation of angle and analog digital amount conversion control circuit monitoring angle degrees of data register, when new data write the angle-data register, the angular metric θ that angle is corresponding according to these data with analog digital amount conversion control circuit solves corresponding Sin θ and Cos θ; The positive full scale of the maximal value 1 corresponding angle data register of data-signal; The negative full scale of the minimum value of data-signal-1 corresponding angle data register; The sine value and the cosine value that solve are write a DA converter and the 2nd DA converter respectively; By a DA converter and the 2nd DA converter Sin θ and Cos θ are delivered to sinusoidal multiplier and cosine multiplier and reference signal respectively and multiply each other, then finish this computing, be automatically brought to then input data signal is discerned, continue said process.At last by sinusoidal voltage lifting and driving circuit with cosine voltage promotes and driving circuit is sent the consequential signal of taking advantage of.

Implementation method of the present invention adopts to use always and easily purchases components and parts, has realized the function and the key technical indexes of digital angle converter DRC chip; And its material cost only is about 2000 yuans, to greatly reduce the cost of DRC chip.

Description of drawings

Fig. 1 is a digital angle converter circuit structure block diagram of the present invention.

Fig. 2 is the workflow diagram of control circuit among the present invention.

Fig. 3 is the test comparison data picture that integrated circuit board carried out of integrated circuit board of the present invention and former employing special digital angle converter DRC chip.

Fig. 4 is the circuit diagram of a specific embodiment of the present invention.

The present invention is described in further detail below in conjunction with embodiment that accompanying drawing and inventor provide.

Embodiment

According to method of the present invention, the realization of digital angle converter comprises the following steps:

1. circuit structure

Its circuit block diagram as shown in Figure 1.According to analysis to DRC chip principle, the development of combined digital signal treatment technology, DRC circuit of the present invention is made of following several parts:

The photoelectrical coupler that is connected with the DA converter, photoelectrical coupler is connected to a DA converter and the 2nd DA converter, the one DA converter is connected with sinusoidal multiplier, the 2nd DA converter is connected with the cosine multiplier, sinusoidal multiplier and cosine multiplier are connected with sinusoidal voltage lifting and driving circuit and cosine voltage respectively and promote and driving circuit, be connected with on wherein sinusoidal multiplier and the cosine multiplier as sine-wave generator, also have the voltage of reference signal to promote and driving circuit on the sine-wave generator with reference to signal.

Photoelectrical coupler also is connected with an angle and analog digital amount conversion control circuit, by angle and analog digital amount conversion control circuit the angular metric θ that imports is calculated, and is connected with the angle-data register on angle and the analog digital amount conversion control circuit.

2. the realization of multiplier

First, second DA converter and multiplier two parts are actually to be finished by a DA converter, method is the digital quantity input end that digital quantity is mail to first, second DA converter, its corresponding simulating amount output is fixed according to the size of reference signal, therefore, the analog that will multiply each other with it is directly connected to the reference signal input end of DA converter, has just realized multiplying each other of analog quantity after the digital quantity conversion and reference signal automatically.

3. calculation of parameter

According to precision is the needs of 14 bit digital angle converter DRC chips, selects for use 16 DA converters to finish the conversion of Y1=Sin θ and Y2=Cos θ; Computational accuracy also intercepting simultaneously is 16; Consider that the required simple harmonic wave frequency of DRC chip is 400Hz～800Hz, so actual frequency is designed to about 500Hz.

Require the frequency response of its large-signal to be simultaneously in the selecting for use of DAC (digital to analog converter): when the error of Vout is not less than 0.006%FSR, must not be lower than 80KHz by frequency, offset voltage must not be greater than ± 2LSBFSRV.

The data variation of angle and analog digital amount conversion control circuit monitoring angle degrees of data register when new data write the angle-data register, is then carried out corresponding calculating to angular metric θ, and computing formula is as follows:

At first the angular metric θ according to input calculates corresponding Sin θ and Cos θ.

$\mathrm{Sin\θ}=\mathrm{\θ}-\frac{{\mathrm{\θ}}^3}{3!}+\frac{{\mathrm{\θ}}^5}{5!}-\frac{{\mathrm{\θ}}^7}{7!}+\·\·\·=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{{(-1)}^{n+1}{\mathrm{\θ}}^{2n-1}}{(2n-1)!}$

$\mathrm{Cos\θ}=1-\frac{{\mathrm{\θ}}^2}{2!}+\frac{{\mathrm{\θ}}^4}{4!}-\frac{{\mathrm{\θ}}^6}{6!}+\·\·\·=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{{(-1)}^{n+1}{\mathrm{\θ}}^{2(n-1)}}{\left[2(n-1)\right]!}$

Then itself and reference signal ViSin ω t are multiplied each other, obtain:

Vo _sin＝ViSinωtSinθ

Vo _cos＝ViSinωtCosθ

At last according to of the requirement of RDC (analog angle and data converter) chip,, draw the output of ViSin ω tSin θ and the ViSin ω tCos θ adjustment that gains to the resolver amplitude:

Vo _sin＝GViSinωtSinθ

Vo _cos＝GViSinωtCosθ

3. angle and analog digital amount conversion control circuit control flow design

Angle and analog digital amount conversion control circuit play a part the control maincenter in whole conversion, the workflow of angle and analog digital amount conversion control circuit has embodied the control thought of entire circuit.

Referring to Fig. 2, after system powers on, at first carry out initialization, then the data of input are discerned, obtain θ; Obtain pairing sine and cosine value Sin θ and Cos θ by calculating; Sin θ and Cos θ are delivered to sinusoidal multiplier and cosine multiplier and reference signal respectively multiply each other, then finish this and handle, control forwards to carries out new identification to the input data, and continues said process.

Concrete principle of work of the present invention is: when the angle-data that will take place as the CPU of control system writes the angle-data register of DRC by data bus, angle in the DRC circuit and analog digital amount conversion control circuit are monitored the data variation of this angle-data register, when new data writes the angle-data register, the angle that angle is corresponding according to these data with analog digital amount conversion control circuit solves corresponding Sin θ and Cos θ; The positive full scale of the maximal value 1 corresponding angle data register value of this data-signal; The negative full scale of the minimum value of this data-signal-1 corresponding angle data register value; The sine and cosine value that solves is write a DA converter (DAC1) and the 2nd DA converter (DAC2) respectively.Because the relation of circuit amplitude, the output of two-way digital to analog converter (DAC1, DAC2) is respectively ViSin θ and ViCos θ.

ViSin θ and ViCos θ are sent to sinusoidal multiplier 1 and cosine multiplier 2, multiply each other with reference signal Sin ω t respectively, and, finally obtain GViSin ω tSin θ and GViSin ω tCos θ through sinusoidal voltage lifting and driving circuit and lifting of cosine voltage and driving circuit realization gain adjustment.

The present invention has realized the function and the key technical indexes of DRC chip; Secondly components and parts of the present invention are the device of easily purchasing commonly used; The 3rd material cost of the present invention only is about 2000 yuans.

The workflow of angle and analog digital amount conversion control circuit can be used chip microcontroller, also can adopt sequential control circuit to realize; Corresponding flow process as shown in Figure 2.

The present invention has been used for the unit testing instrument of certain equipment, after tested proof: 84 measured values that carried out are all qualified, and maximum error is 2 LSB, and have only a measured value.Fig. 3 is the test comparison data that integrated circuit board carried out of integrated circuit board of the present invention and the special-purpose DRC chip of former employing.

According to method of the present invention, the applicant provides a specific embodiment, as shown in Figure 4, entire circuit comprises that one of eight of one of two of data register 54HCT373, code translator GAL16V8, optical coupling isolator HCPL-5630, single chip computer AT 89C51, one of two of DA converter AD7849, sinusoidal signal generator MAX038, four of operational amplifier OPA2227, voltage promote three of operational amplifier OPA445, boosting voltage and produce each one of circuit LM337T and LM317T.

The ultimate principle of this circuit is as follows:

P1 among the figure, P2 are two bus plugs, and it is the interface of certain DRC circuit board and host CPU, and when this circuit was used for other system, its attachment plug was not necessarily identical therewith, and it just sets up the annexation of DRC circuit and host CPU.

By host CPU the data register (two 54HCT373) that hangs on the bus is carried out the write operation of angle-data; The output of data register is delivered to 14 isolated data respectively on the P0 and P2 mouth of single-chip microcomputer (AT89C51) by 8 opto-coupler chips, single-chip microcomputer is gathered the data variation of these two mouths and is differentiated, when finding that data change, carry out data computation (Sin θ and Cos θ) immediately, and result of calculation is sent to DA converter (two AD7849) respectively, MAX038 is responsible for producing the standard sine wave signal, after this sine wave signal amplifies through OPA2227 (D17A), be sent to the reference signal input end (the VREF+ end of D13 and D14) of DA converter, the output of two DA converters is sent to OPA2227 (D16A and D16B) respectively and carries out voltage follow, and D18 is sent in the output of follower and D19 (OPA445) carries out the voltage lifting; Be sent to OPA2227 (D17B) through the sine wave signal after OPA2227 (D17A) amplification and carry out voltage follow, the output of follower is sent to D20 (OPA445) and is carried out the voltage lifting; Finally finished the generation of three signals (sinusoidal signal, cosine signal, reference signal).

D21 (LM7905) produces required-5V voltage for MAX038; D22 and D23 (LM337T and LM317T) provide ± the 20V power supply for operational amplifier (OPA445).

They are exactly to connect the concrete application circuit of realization according to the present invention, and have been applied in the unit testing instrument of certain model.

Claims (3)

1. the implementation method of a digital angle converter is characterized in that, comprises the following steps:

The first, at first determine circuit structure, its structure comprises:

An optocoupler circuit, be connected with a DA converter and the 2nd DA converter on this photoelectrical coupler respectively, the one DA converter is connected with sinusoidal multiplier, the 2nd DA converter is connected with the cosine multiplier, sinusoidal multiplier and cosine multiplier are connected with sinusoidal voltage lifting and driving circuit and cosine voltage respectively and promote and driving circuit, be connected with on wherein sinusoidal multiplier and the cosine multiplier as the sine-wave generator with reference to signal, the output of sine-wave generator has the voltage of reference signal to promote and driving circuit;

Photoelectrical coupler also is connected with an angle and analog digital amount conversion control circuit, is used for the angular metric θ of input is carried out corresponding calculating, also is connected with the angle-data register on angle and the analog digital amount conversion control circuit;

Photoelectrical coupler is used for digital control circuit and DRC simulating signal are kept apart, to improve the precision of drc signal; When system does not require isolation, also can save photoelectrical coupler;

Second, the data variation of angle and analog digital amount conversion control circuit monitoring angle degrees of data register, when new data-signal write the angle-data register, the angular metric θ that angle is corresponding according to these data with analog digital amount conversion control circuit solved corresponding Sin θ and Cos θ; The positive full scale of the maximal value 1 corresponding angle data register of data-signal; The negative full scale of the minimum value of data-signal-1 corresponding angle data register; The sine value and the cosine value that solve are write a DA converter and the 2nd DA converter respectively; By a DA converter and the 2nd DA converter Sin θ and Cos θ are delivered to first multiplier and second multiplier and reference signal respectively and multiply each other, then finish this and handle, be automatically brought to then input data signal is carried out new identification, and continue said process.

2. the method for claim 1, it is characterized in that, described first, second DA converter is actually by a DA converter and is achieved with sinusoidal, cosine multiplier two parts, its implementation is the digital quantity input end that digital quantity is mail to first, second DA converter, its corresponding simulating amount output is fixed according to the size of reference signal, therefore, the analog that will multiply each other with it is directly connected to the reference signal input end of DA converter, just can realizes multiplying each other of analog quantity after the digital quantity conversion and reference signal automatically.

3. the method for claim 1 is characterized in that, the computing formula that described angle and analog digital amount conversion control circuit relate to is:

$\mathrm{Sin\θ}=\mathrm{\θ}-\frac{{\mathrm{\θ}}^3}{3!}+\frac{{\mathrm{\θ}}^5}{5!}-\frac{{\mathrm{\θ}}^7}{7!}+\·\·\·=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{{(-1)}^{n+1}{\mathrm{\θ}}^{2n-1}}{(2n-1)!}$

$\mathrm{Cos\θ}=1-\frac{{\mathrm{\θ}}^2}{2!}+\frac{{\mathrm{\θ}}^4}{4!}-\frac{{\mathrm{\θ}}^6}{6!}+\·\·\·=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{{(-1)}^{n+1}{\mathrm{\θ}}^{2(n-1)}}{\left[2(n-1)\right]!}$

Then itself and reference signal are multiplied each other, obtain:

Vo _sin＝ViSinωtSinθ

Vo _cos＝ViSinωtCosθ

Last according to of the requirement of RDC chip to the resolver amplitude, by voltage promote and driving circuit to the output of ViSin ω tSin θ and the ViSin ω tCos θ adjustment that gains, draw:

Vo _sin＝GViSinωtSinθ

Vo _cos＝GViSinωtCosθ。

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