JP6212694B2 - A / D conversion method and apparatus - Google Patents

Description

  The present invention relates to an A / D conversion method and apparatus, and more particularly to a novel improvement for simplifying a circuit configuration by not including the polarity of an analog signal during A / D conversion.

  In this type of A / D converter that has been used conventionally, in order to obtain absolute value digital data by A / D conversion, (1) an analog signal is converted into an absolute value signal by an analog absolute value circuit. Later, there are two methods: A / D conversion method and (2) A / D conversion of an analog signal and then converting it into an absolute value by a digital absolute value circuit.

As for the A / D conversion common to the above-mentioned two methods, the flash type high resolution A / D converter of Non-Patent Document 1 can be cited as a representative, and usually according to the potential difference with respect to the reference value of the input analog signal. Digital data is output.
As for the above-described absolute value circuit, as the analog absolute value circuit of (1) described above, a circuit as shown in FIG. 11-14 of Non-Patent Document 2 is known, and the digital absolute value circuit of (2) above is known. For example, there is a method of inverting data based on the polarity code of digital data.

  The R / D converter disclosed in Patent Document 1 is a method of obtaining an absolute value of data and using it for signal processing after A / D conversion.

JP 2004-301806 A

December 2006 issue “Transistor technology”, pages 10-11 “Use AD converter ICs”. “Absolute value circuit” in FIG. 11-14 on page 312 of “OP amplifier circuit design” published in the 20th edition of 2004.

Since the conventional A / D conversion method is configured as described above, the following problems exist.
In other words, the method (1) described above requires an analog absolute value circuit and it is difficult to simplify the circuit. In the method (2), after the analog / digital conversion including the polarity of the analog signal is performed. Therefore, the absolute value is obtained by the digital signal processing, and the circuit for performing the analog / digital conversion is to be enlarged.
Further, the configuration of Patent Document 1 described above is a method for obtaining the absolute value of data after A / D conversion and using it for signal processing, and thus is not suitable for circuit miniaturization.

  The present invention has been made in order to solve the above-described problems. In particular, an A / D circuit which can be made smaller in size than the conventional one by not including the polarity of an analog signal during A / D conversion. An object is to obtain a D conversion method and apparatus.

  An A / D conversion method according to the present invention comprises an absolute value A / D converter comprising an analog / digital converter and a digital signal processor for inputting digital data and analog signal polarity from the analog / digital converter. The absolute value A / D converter has a comparison signal polarity switching circuit for switching the polarity of the comparison signal used for comparison with the analog signal in the analog / digital conversion unit according to the polarity of the input analog signal; A digital data polarity switching circuit for switching the polarity of digital data in accordance with the polarity of the analog signal in the digital signal processing unit, and obtaining absolute value data from the digital signal processing unit, and the comparison signal The polarity switching circuit selects the comparison signal having the same polarity as the analog signal from two comparison signals having the same absolute value but different polarities. The comparison signal polarity switching circuit selects a reference signal having the same polarity as that of the analog signal among the reference signals having the same absolute value data and different polarities. The A / D converter according to the present invention is a method for inputting the analog / digital converter and the digital data and the analog signal polarity from the analog / digital converter. An absolute value A / D converter composed of a signal processing unit, and the absolute value A / D converter compares the analog signal with an analog signal in the analog / digital conversion unit according to the polarity of the input analog signal. A comparison signal polarity switching circuit that switches the polarity of the comparison signal to be used, and the digital signal processing unit switches the polarity of the digital data according to the polarity of the analog signal. A digital data polarity switching circuit that obtains absolute value data from the digital signal processing unit, and the comparison signal polarity switching circuit includes two comparison signals having the same polarity but different absolute values, The comparison signal having the same polarity as the analog signal is selected and used for comparison with the analog signal, and the comparison signal polarity switching circuit is a reference signal having the same absolute value data but different polarity, A reference signal having the same polarity as that of the analog signal is selected and used to generate the comparison signal.

Since the A / D conversion method and apparatus according to the present invention are configured as described above, the following effects can be obtained.
That is, an absolute value A / D converter including an analog / digital conversion unit and a digital signal processing unit for inputting digital data and analog signal polarity from the analog / digital conversion unit, the absolute value A / D The D converter includes a comparison signal polarity switching circuit for switching the polarity of a comparison signal used for comparison with an analog signal in the analog / digital conversion unit according to the polarity of the input analog signal, and the analog signal processing unit in the analog signal processing unit. A digital data polarity switching circuit that switches the polarity of digital data according to the polarity of the signal, and by obtaining absolute value data from the digital signal processing unit, A / D conversion of the polarity of the analog signal can be omitted. The circuit of the part can be reduced as compared with the conventional circuit, and the A / D converter can be reduced in size and reduced by simplifying the circuit. Kakuka can be achieved.
The comparison signal polarity switching circuit selects the comparison signal having the same polarity as the analog signal from two comparison signals having the same polarity and having the same absolute value, and uses the comparison signal for comparison with the analog signal. The effect of can be further clarified.
The comparison signal polarity switching circuit selects the reference signal having the same polarity as the analog signal from among the reference signals having the same absolute value data and different polarities, and uses the same to generate the comparison signal. Can be further clarified.

1 is a block diagram illustrating an A / D conversion method and apparatus according to the present invention. FIG. 2 is a circuit diagram illustrating a specific example of a comparison signal polarity switching circuit and a digital data polarity switching circuit of FIG. 1. It is a circuit diagram which shows the other form of FIG.

  The present invention is to simplify the circuit configuration by not including the polarity of the analog signal during A / D conversion.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of an A / D conversion method and apparatus according to the present invention will be described with reference to the drawings.
In FIG. 1, what is indicated by reference numeral 200 is an improved absolute value A / D converter according to the present invention, and this absolute value A / D converter 200 is an analog / digital converter having a comparison signal polarity switching circuit 300. A conversion unit 301 and a digital signal processing unit 303 having a digital data polarity switching circuit 302 connected to the analog / digital conversion unit 301 are configured.

  An analog signal F (t) is input to the analog / digital converter 301, and digital data 301a and analog signal polarity 301b output from the analog / digital converter 301 are input to the digital signal processor 303. The digital signal processing unit 303 is configured to output absolute value data 200a.

  The absolute value A / D converter 200 shown in FIG. 1 is a well-known flash type analog / digital conversion base, and the comparison signal polarity switching circuit 300 has two ( Among the comparison signals (positive side and negative side), a reference signal having the same polarity as F (t) is selected and a comparison signal is generated and used for comparison with F (t).

That is, as shown in FIG. 2, a number of comparators CMP _POL , CMP ₁ , CMP ₂ corresponding to the digitization resolution are provided on the rear stage side of the comparison signal polarity switching circuit 300 in the analog / digital conversion unit 301. ··· _{CMP n-1, CMP} n are provided, each of the comparators _CMP 1 _~CMP latch circuit At the the number of horses in response to the output OUT side of the _{n LT 1, LT 2 ··· LT} n-1, LT _n is provided.

The digital data 301a from each of the latch circuits LT _{1 to} LT _n is one of the selector 1, the selector 2, the selector n-1, and the selector n of the digital data polarity switching circuit 302 subsequent to the analog / digital converter 301. Input to the input terminal A, and the other input terminal B is connected with the digital data 301a inverted through an inverter 1v.

The outputs S _{1 to} Sn of the selectors _{1 to n} are configured to obtain absolute value data 200 a composed of LSB, LSB + 1,... MSB−1, MSB via the binary encoder 400.
The digital data polarity switching circuit 302 is not limited to the configuration shown in FIG.

The comparison signal polarity switching circuit 300 provided in the preceding stage of each of the comparators CMP _{POL to} CMP _n is provided with a number corresponding to the resolution between a predetermined set voltage + V _ref and −V _ref and connected in series to each other. R _{− (n + 1)} , R _−n ... R ₋₃ , R ₋₂ , R ₋₁ , R ₊₁ , R ₊₂ , R ₊₃ ... R _{+ n} , R _{+ n + 1} , and each resistance R _{− (n + 1) ~R + n} + 1 forms the well-known ladder network, the negative terminal T of the comparison signal _{V B} consisting of the divided voltage divided is the respective comparators CMP ₁ ~CMP _{n -} the connected electronic type on / OFF switches SW ₋₁ , SW ₊₁ , SW ₋₂ , SW ₊₂ ... SW _{− (n−1)} , SW _{+ (n−1)} . It is connected to SW− _n and SW _{+ n} .

Among the respective divided voltage _{V B,} the comparison signal comprising a divided voltage _{V B1} between the resistor _{R -1} and _{R +1,} the comparator _{CMP POL} of T _- is directly input to this comparator _{CMP POL} and the The analog signal F (t) is directly input to the positive terminals T ₊ of the comparators CMP _{1 to} CMP _n .

In FIG. 2, the comparator CMP _POL is a comparator for selecting a polarity, and an analog signal polarity 301 b from the comparator CMP _POL is an inverter to the switches SW _{1 to} SW _−n of the comparison signal polarity switching circuit 300. 1 is input via _V1 , is directly input to the switches SW _{+ 1 to} SW _{+ n} , and is simultaneously input to the selectors 1 to n.

Thus, the analog signal the input to the analog / digital converter section 301 F (t) is input to the positive terminal _{T +} of the comparator _CMP POL _{~CMP n,} each comparison signal _{V B} is the negative terminal T _- is input to, the analog signal polarity 301b is inputted directly or through inverters _{I V1} from said respective _{SW -1} to _{SW + n,} the positive or negative only analog signal in polarity each latch _LT 1 to LT analog signal F (t) Through _n , the digital data 301a passes through the selectors 1 to n, passes through the selectors 1 to n, and is input to the binary encoder 400 to obtain absolute value data 200a.

The analog signal polarity 301b is input to the switches SW _{- 1} to SW _{+ 1} and simultaneously input to the selectors 1 to n, and whether the digital data 301a is directly input to the binary encoder 400. Alternatively, the signal is inverted via each inverter 1 _V and input to the binary encoder 400.

The analog signal polarity 301b is output according to the positive / negative of the F (t) input to the comparator CMP _POL, and the switches SW- _{1 to} SW _{+ n} and the selectors 1 to 1 are output by the analog signal polarity 301b. n is switched, and positive or negative digital data 301 a is input to the binary encoder 400.

Therefore, the comparison signal polarity switching circuit 300 having all the switches SW _{−1 to} SW ₊₁ and the digital data polarity switching circuit 302 are automatically switched according to whether the analog signal polarity 301b is positive or negative, as in the prior art. The conversion of the polar part in the analog signal F (t) does not need to be digitally processed, and the circuit configuration of the A / D converter can be significantly reduced as compared with the prior art.

FIG. 3 shows another form of the absolute value A / D converter 200 of FIG. 1, except that the comparison signal polarity switching circuit 300 is different from the structure of FIG. 2, and the other structure is the same as FIG. Therefore, the comparison signal polarity switching circuit 300 will be described.
That is, in FIG. 3, the first switch SW _a is connected to the power source −V _ref, and the analog signal polarity 301 _b is connected to the first switch SW _a via the inverter I _V1 .

The second switch SW _b connected to the power source + V _ref is electrically connected to the first switch SW _a , and each series resistor for outputting the comparison signals V _B and V _B1 described above. The comparison signals V _B and V _B1 are connected to R _{1 to} R _{n + 1} and input to the negative terminals T ₋ of the comparators CMP _{1 to} CMP _n and CMP _POL .
Of the converters CMP _POL to CMP _n , the analog signal polarity 301b output from the converter CMP _{POL is} input to the first switch SW _a via the inverter I _V1 and directly input to the second switch SW _b. Has been.

Thus, the analog signal polarity 301b is positive, if negative one, either switch _SW a, SW _b is switched, the digital data 301a of the positive or negative side sent to each selector _S 1 to S _n of the above are, each selector _S 1 to S _n is also the switches _SW a by the analog signal polarity 301b, positive and negative in synchronism with the SW _b is switched without data the signal polarity, the absolute value data 200a Can be output.

The configuration of the absolute value A / D converter 200 in FIG. 3 is a well-known flash type A / D converter, and the comparison signal polarity switching circuit 300 has a reference (not shown) having the same absolute value but different polarity. Among the signals, a reference signal (not shown) having the same polarity as the analog signal is selected and used to generate a comparison signal.
The above-described configuration switches the polarity of a reference signal (not shown), and A / D conversion can be applied to a wide variety of systems as long as the comparison signal is generated from the reference signal (not shown) instead of the flash type described above.
Further, the digital data polarity switching circuit 302 is not limited to the preceding stage of the binary encoder 400, and the same operation can be obtained when it is provided in the subsequent stage.

Next, the above embodiment is summarized as follows.
That is, it has an absolute value A / D converter 200 comprising an analog / digital conversion unit 301 and a digital signal processing unit 303 for inputting the digital data 301a and the analog signal polarity 301b from the analog / digital conversion unit 301. ,
The absolute value A / D converter 200 switches the polarity of the comparison signal used for comparison with the analog signal F (t) in the analog / digital conversion unit 301 in accordance with the polarity of the input analog signal F (t). A comparison signal polarity switching circuit 300; and a digital data polarity switching circuit 302 that switches the polarity of the digital data 301a in accordance with the polarity of the analog signal F (t) in the digital signal processing unit 303, and the digital signal processing unit The A / D conversion method and apparatus is characterized in that the absolute value data 200a is obtained from the signal 303, and the comparison signal polarity switching circuit 300 includes the analog signal among two comparison signals having the same absolute value but different polarities. An A / D conversion method and apparatus characterized in that the comparison signal having the same polarity as the signal F (t) is selected and used for comparison with the signal analog F (t). Also, the comparison signal polarity switching circuit 300, among the absolute value data 200 a is the same polarity different reference signals, the generation of said comparison signal to select the same polarity reference signal and the analog signal F (t) An A / D conversion method and apparatus characterized by being used.

  The A / d conversion method and apparatus according to the present invention can provide an inexpensive A / D converter with a simplified circuit configuration by not including the polarity of an analog signal during A / D conversion.

F (t) Analog signal
200a Absolute value data 300 Comparison signal polarity switching circuit 301 Analog / digital conversion unit 301a Digital data 301b Analog signal polarity 302 Digital data polarity switching circuit 303 Digital signal processing unit 400 Binary encoder V _B comparison signal I _V , I _V1 Inverter SW ₋₁ ~ SW _{+ n} switch CMP _POL ~ CMP _n comparator LT1 ~ LT _n latch circuit ₁ ~ _n selector

Claims (6)

An absolute value A comprising an analog / digital conversion unit (301) and a digital signal processing unit (303) for inputting digital data (301a) and analog signal polarity (301b) from the analog / digital conversion unit (301). / D converter (200)
The absolute value A / D converter (200) is a comparison signal used for comparison with the analog signal F (t) in the analog / digital converter (301) according to the polarity of the input analog signal F (t). And a digital data polarity switching circuit (300) for switching the polarity of the digital data (301a) in accordance with the polarity of the analog signal F (t) in the digital signal processing unit (303). 302), and obtaining the absolute value data (200a) from the digital signal processor (303).   The comparison signal polarity switching circuit (300) selects the comparison signal having the same polarity as the analog signal F (t) from two comparison signals having the same absolute value but different polarity, and selects the analog signal F (t). The A / D conversion method according to claim 1, wherein the A / D conversion method is used for comparison with. The comparison signal polarity switching circuit (300), the absolute value data (200 a) is of the same polarity different reference signal, the comparison signal to select the same polarity reference signal and the analog signal F (t) The A / D conversion method according to claim 1, wherein the A / D conversion method is used for generation. An absolute value A comprising an analog / digital conversion unit (301) and a digital signal processing unit (303) for inputting digital data (301a) and analog signal polarity (301b) from the analog / digital conversion unit (301). / D converter (200)
The absolute value A / D converter (200) is a comparison signal used for comparison with the analog signal F (t) in the analog / digital converter (301) according to the polarity of the input analog signal F (t). And a digital data polarity switching circuit (300) for switching the polarity of the digital data (301a) in accordance with the polarity of the analog signal F (t) in the digital signal processing unit (303). 302), and obtains absolute value data (200a) from the digital signal processing unit (303).   The comparison signal polarity switching circuit (300) selects the comparison signal having the same polarity as the analog signal F (t) from two comparison signals having the same absolute value but different polarity, and selects the analog signal F (t). The A / D converter according to claim 4, wherein the A / D converter is used for comparison with the A / D converter. The comparison signal polarity switching circuit (300), the absolute value data (200 a) is of the same polarity different reference signal, the comparison signal to select the same polarity reference signal and the analog signal F (t) The A / D conversion apparatus according to claim 4, wherein the A / D conversion apparatus is used for generation.

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