SU809544A1 - Method and device for matching precise and coarse readings of analogue-digital converter - Google Patents

Description

(54) METHOD FOR APPROVAL OF EXACT AND COARSE

CALCULATIONS ANALOG-DIGITAL CONVERTER AND DEVICE FOR ITS IMPLEMENTATION

The invention relates to an analog-to-digital conversion, to cyclic converters of sequential counting, and can be used in two-scale reference systems in which the ratio of the scales of the scales is determined by electronic or mechanical reduction.

Methods are known in which, when matching the readings, the codes are corrected. The matching algorithm is reduced to the fact that after fixing the values of the exact and coarse sample codes (TO and GO), the correctness of the GO readings is analyzed and, if necessary, corrected, for which special matching bits are used that do not participate directly in the l conversion.

However, in these methods, when the value of the parameter in GO at the input of the transducer changes, an asymmetry of the read pulse relative to its neighboring (right and left) counter pulses DT appears, and the minimum distance between the count and counter pulses can be close to zero and. fluctuations of the GO counting pulse may appear discrete error.

There is also known a method for matching the exact and coarse readings of an analog-digital converter by successively and coherently converting the phase of the input signal into a code with a selection of counting pulses in a time interval of 2J.

The disadvantages of this method are the limitation of the fluctuation zone of the reference pulse GO and the lack of adjustment for eliminating systematic and random error, which can lead to a mismatch of coarse and accurate readings.

The purpose of the invention is to increase the reliability of matching accurate and coarse readings.

This goal is achieved by matching the exact and coarse readings of the analog-digital converter by successively and coherently converting the phase of the input signal into a code with a selection of counting pulses over a time interval, an additional selection of counting pulses of a coarse counting time interval of which is synchronized and reduced counting coarse pulses, and delay them in time with the current value of the exact count, greater than or equal to 0.5 MfQ, depending on from the current value of the exact reading, the delay value is set to be less than or equal to 1.5 MYO and more than r-D MTQ. - the scale of the exact reference, and in the device implementing the method containing the following filter, the first output of which is through the phase-interval converter of the exact reference. and the first element I is connected to the input of the counter of the exact counter, the second output through the phase-interval converter is coarse reference and the second element And is connected to the input of the coarse counter, an adjustable delay element, a set of two-input elements AND, a first and second delay element, an OR element, a third AND element, and moreover, n outputs of the exact counter Dineny with the first inputs of two-input elements And, the second inputs of which are from the first to (k- - 1) are connected to the outputs of the first delay element, and the inputs (with the outputs of the second delay element, all the outputs of the two-input elements AND are connected to the inputs of the OR element, the output of which connected to the second input of the second element and, the input of the first delay element and the first input of the third element And solenoid with the output of the tracking filter, the second input of the second element And connecting it with the output of the converter, the phase of the coarse readout element This delay is included in the reference sine wave to the input of the phase-interval of the exact reference transducer. The drawing shows a functional electrical circuit of the device. Suppose that at the beginning of the conversion the phase shift according to the exact reading is equal to the correspondence of the indicated shift to the converter 1 phase-interval forms the pulse strobe o and the outputs of the element 2, i.e. a stack of checks, tny impulses, the counter 3 calculates the impulses of the pack and records the code. For the specified value, the code of one of the n-th outputs of counter 3 appears resolving POT, received at the input of one of the n two-input (output elements AND 4, the other input of this element receives counting pulses of a rough count from the tracking filter of the rangefinder 5 through the delay element 6 (at: 0.5 MTO) or through element I, delay element 8 (at 0.5 P where MTO is the scale of the exact reference, and qj is the current value of TO. Counting coarse counting pulses through the element OR 9 are passed to the input of the element AND 10, at the other input comes a pulse strobe then, from the output element and AND 10, counting pulses are received at counter coarse counter 11. Coordination of counts is reduced to ensure that when there are restrictions for a two-way tracking rangefinder on fluctuation, tracking speed, etc., provide a miscalculation of coarse read pulses from an And 10 element without an error of one Discreteness. At the second output of the counter 3, a resolving potential is formed, which is fed to the input of the second element 1.1.1 and 4, which is connected to the second output of the delay element b by its second input. Through the second element And 4 pass counting pulses with a delay of 0.7 0.7. These pulses pass through the element OR 9 and are gated with element 10, and there is no counter pulse at its output. Thus, at 0.2 M th AT 0.5 MTQ What I At the 4th output of counter 3, the resolving potential is formed, which is fed to the element 4, through which counting pulses with a delay fj.j 0.9 MTO will pass. After gating with the AND 10 element, a single pulse arrives at the input of the counter 11, i.e. at 1 and MTO DTZ. 0.5 MTO- 4to 1.5 At the input of the fifth element And 4, igshulsy come from the delay element 8 (f ,, 1.0 Who) In this lTZ 0.5 MTO "For the specified case (at 0.5 MTU) are counting Impulses are gated twice. First, at the output of the element And 7 two pulses, then after their delay at the output of And 10 one pulse, 1.8 MTQNa. The input of the delay element 8 receives gated pulses, in it they are delayed by a value of 3-4 16.3 MTO and arrive through the element OR 9 to the input of AND 4, from the output of it after the second gating, one I1 1 pulse arrives at the input of the GO counter 11. qTo 2.0 MTeV value 1GD 1.5 Who /% 0.5 M Element 12 is used to shift the zeros of the zeros-ShksSh. it in the chain of exact reference makes it possible to reduce the error introduced by him during adjustment by m times, where m: -, M go is the scale coarse scale. Thus, the proposed device increases the reliability of matching the counts due to the fact that during the conversion the readout pulse, being constantly in the middle between the counting pulses on a coarse scale, makes it possible to increase the tracking speed value or work with

large fluctuations of the reference GO pulse, the device contains a simple scheme for eliminating the "extra unit in which the AND element associated with the sources of the time interval gb and counting GO pulses is used, eliminating the effect of the systematic and random errors of the range finder on the accuracy of matching, which is done specially introduced by the adjustable delay element. I The phase-to-interval converter 13 forms at the output a strobe pulse n, the trailing edge of which is used to generate a signal% conversion.

Claims (2)

1. Method of matching accurate and coarse samples of analog-to-digital converter by sequential accurate and coarse conversion of the phase of the input signal into a code with the selection of counting pulses by the time interval, that is, and with the fact that, in order to increase the reliability of matching the exact and coarse readings, an additional selection of the counting coarse counting pulses by the time interval, the beginning of which synchronizes and reduces counting pulses of a rough reference, and ead | They are sewed in time with an exact readout greater than or equal to 0.5 MTO, and depending on the current value of the exact readout, the delay is set to less than or equal to 1.5 MtVN more than where the MTQ scale is the exact readout. 2. The device according to PL, contains a following filter, the first output of which is through the phase-interval converter of the exact counting and the first element. And connected to the input of the counter of the exact counting, the second output through the phase-interval converter of the coarse reference and the second element And is connected to the input coarse count counter, characterized in that an adjustable delay element is introduced into it, a set of two-input elements AND, the first and second delay elements, an OR element, a third AND element, and the outputs of the exact count counter are connected to the first inputs of two-input elements and, secondly the first to first (-j - 1) inputs are connected to the outputs of the first delay element, and the (- - n) inputs to the second delay element outputs, all the outputs of the two-input AND elements are connected to the inputs of the OR element, the output of which is connected to the second input of the second element And, the input of the first delay element and the first input of the third element And are connected to the output of the following filter, the second input of the second element And is connected to the output of the phase-interval converter of the coarse count, the element of the adjustable jumper is on into the reference sine wave to the input Phase-interval converter of exact counting. sources of information taken into account in the examination 1. Glagolev I.P. and Smirnov A.K. Coordination of counts in the multi-count converter. Collection of works NIIDI, vyp.Z, 1970, p., 80-91. 2 "USSR author's certificate of application 2117569/21, 04.24.75 (prototy).