SU901932A1 - Device for determination of two frequency ratio and ratio logarithm - Google Patents

Description

The invention relates to a measuring technique and can be used in measuring devices, as well as in functional measuring converters. A device is known that contains a reverse version, a counter, two groups of coincidence elements, a delay element, an OR element, a key, a reference frequency generator, a control unit, and two input formers P1. The disadvantage of this device is the impossibility of determining the logarithm of the ratio of two frequencies. The closest in technical essence to the proposed u trio contains a clock generator, two triggers, two keys, two counters, a forming device, a delay element and a group of elements I 21. However, this device does not measure the logarithm of the ratio of two frequencies, which narrows the class of tasks. The purpose of the invention is to expand the functionality. The goal is achieved by the fact that. into the device for determining the ratio and the logarithm of the ratio of two frequencies, containing the first trigger, the output of which through the first key is connected to the input of the first counter, the second three) - the ger, whose single output is connected to the first input of the second key and the second counter, the discharge outputs of which are connected To control the inputs to the first block of the AND elements, and the setup input is connected to the output of the first delay element, the addition and subtraction block, the third key, the three OR elements, the second block of the AND elements, the second delay element, NT And, the third trigger and switch, the first output of which is connected to the output of the first element OR and the input of the second delay element, the second output is connected to the output of the element AND, and the common output is connected to the zero input

the first trigger, the unit input of which is connected to the unit input of the second trigger and the zero input of the third trigger, the unit input of which is connected to the output of the second counter and the first input of the first element OR, the second input of which is connected to the signal inputs of the first block of elements And, the outputs of which are connected to the bit the first inputs of the first counter, the output of which is connected to the first input of the AND element, the second input of the first OR element, and the input of the first delay element, and times | The serial outputs are connected to the control- / cym inputs of the second block of AND elements, the signal inputs of which are connected to the bit outputs of the second counter, and the outputs are connected to the inputs of the second OR element, whose output is connected to the first input of the addition-reading unit, the second input which is connected to the output of the first key, and the output is connected to the first input of the third key, the second input of which rio is connected to the zero output of the second trigger and the second input of element I. And the output is connected to the first input of the third element OR, the output of which is li ne to the input of the second counter, and a second input connected to the output second-key, wherein the second delay element ment output is connected to the zero input of the second flip-flop. FIG. 1 shows a block diagram of the device; in fig. 2 shows embodiments of a puff block. The device contains counters 1 and 2, blocks 3 and 4 elements AND, block 5 addition-subtraction, triggers 6-8, keys 9-11 elements OR, elements 15 and 16-delays, switch 17 and; element AND 18. Execution of the block 5 Readings are possible in two different ways. In the first variant (Fig. 2a), block 5 consists of one element OR 19t. In the second variant (FIG. 2 b), block 5 consists of trigger 20, element AND 21, delay element 22 and element OR 23. The device operates as follows. In the mode of determining the ratio of two frequencies, the switch 17 finds with in the position 2. After the start commands start on the single inputs of the trigger 6 and 7, the keys 9 are opened

and 10, and hippuls, the following frequencies of which are f / and f, are fed to the inputs of counters 1 and 2, respectively. The key 11 is closed.

When the ratio of the frequencies fg f through the time interval, which is determined by the expression

Nm

(one)

WITH,

counter 2 overflow occurs, where Nm is the conversion factor of counters 1 and 2.

8 this moment in the counter 1 is fixed the number

 f. s „1.

(2).

 g:

t

 l f

Lh

Claims (2)

The overflow pulse of the counter 2 sets the triggers 6 and 7 to the zero state, the keys 9 and 10 are closed, and the determination of the ratio of two frequencies is completed. In addition, the overflow pulse of the counter 2 sets the trigger 8 to the single position corresponding to the case, fg fi. When the frequency ratio f fg is through the time interval, which is determined by the expression T. (3) counter 1 overflows. 8 this moment in counter 2 records the number NH ta fa М „, the overflow pulse of counter 1 rewrites the number N from counter 2 to counter 1 and after a time tjt determined by delay element 15, sets counter 2 to zero position. In addition to the pulse, the overflow pulse of the counter 1 sets the triggers 6 and 7 to the zero state, the keys 9 and 10 are closed, and the process of determining the ratio of the two frequencies is completed. The trigger 8 in this case remains in the zero position, which corresponds to the case of f fa. In the logarithm of the two frequencies, the switch 17 is in position 25. Until the counter overflows 1 or 2, depending on the ratio of frequencies and%, the calculation process , similar to that described above. As a result, the number 1 is fixed in the counter 1 or the state of the trigger 8 determines the impulse frequency ratio t. overflowing one of the counters. 59 passes through elements 12 and 16, sets trigger 7 to the zero state. The key 10 is closed, and the key 11 is opened. Key 9 remains open. In case of public keys 9 and 11, the device includes C blocks of AND elements, the element OR 13, and block 5 of addition and subtraction. In the first variant of construction, block 5 is a frequency addition scheme whose pulse frequency at the output is determined by the expression% f, f / b (t). (5) where) is the frequency of the pulses at the output of the element 13. The control of the blocks of the elements And, in the first variant of building the block S, is performed by the inverse code of the number contained in the counter 1. Counters 1 and 2, the blocks of the k elements And, and the element ISH 13 is a binary multiplier, the frequency of the pulses at the output of which is determined by the equation N4oyW Nm. where WtoSW is the inverse code of the number of NiCt) currently contained in counter 1. Given expression (5), we obtain ld Taking into account the approximate equalities Nm - Ni ((t) U (t), we have% (t) - g f. (8 5) of the second variant of construction, block 5 is a combined addition-subtraction scheme; trigger 20, AND 21 and delay element 22 serve to subtract frequencies, and OR 23 to add frequencies. Pulse frequency at the output of block 5 is determined is made by the expression f5 fi ifb (t) -, f4 (t). (9). The control of the block 4 of elements AND, in the second variant of the construction of block 5 is performed by the direct code of contained in the counter 1. Consequently, the frequency of the pulses at the output of element 26 OR 13 is determined by the expression of Resh, together equations (9) and (10) again arrive at equation (8). Thus, in both variants of building block 5 and the corresponding variants of block control The k elements And, the frequency of the pulses at the output of block 5 is determined by the expression (8). The frequency fg (t) of the pulses fed to the input of counter 2 is related to the number N2 (1) contained in counter 2 by the equation .m.JailL L ) .. taking into account the expression. C8) we get the Frequency f, input to the counter 1, is connected with the number N, (t) contained in this counter, the expression - Dividing equation (12) into equation (13) and divising the variables, we get (U) . dN, (i) N -15 The process of determining logs (the two-frequency ratio ends at the moment of overflow of counter 1. Pulse overflow, passed through element 18 and switch 17, switches trigger 6 to the zero state, and key 9 closes. With frequency ratio f ft, for the time elapsed from the moment of overflow of counter 2 to the overflow of counter 1, the number N (t) in counter 14 1 changes from N to Nm, while in counter 2 the number M changes FROM P to Na i where Na is the result determine the logarithm of the ratio of two frequencies. By integrating equation (T) taking into account the limits changes of variables we get (5)., -e "Taking into account the expression (2), we have m, At the frequency ratio f / i tg, for the time elapsed from the first overflow of counter 1 to the moment of its second overflow, the number N /, ( t in counter 1 varies from N; to Nm and in counter 2, the number N2 (1) changes from O to NS, where Ng is the result of determining the logarithm of the ratio of two frequencies. By integrating equation (C) and taking into account the limits of change of variables, we get J dNatt in m; Taking into account the expression (k), we have N2. (20). The overflow impulse of counter 1 rewrites the number Hg or Ng obtained in counter 2 to counter 1. Consequently, in counter 1, depending on the selected operation mode of the device, a number proportional to the ratio of two frequencies or the logarithm of the two frequencies is recorded, and the state The outputs of trigger 8 indicate which of the two frequencies is greater than the other. Thus, by slightly complicating the device, an extension of the class of problems to be solved has been achieved by making it possible to determine the logarithm of the ratio of two frequencies. The invention The device for determining the ratio and the logarithm of the ratio of two frequencies that contains the first trigger, the output of which is connected via the first key to the input of the first counter, the second trigger, whose single output is connected to the first input of the second key and the second counter, the output outputs to the second connected to the control inputs of the first block of elements And, and the installation input is connected to the output of the first delay element, characterized in that, in order to expand its functionality, an addition block is introduced into it third key, three elements OR, second block of AND elements, second delay element, And element, third trigger and switch, the first output of which is connected to the output of the first OR element and the input of the second delay element, the second output is connected to the output of the AND element, and the common output is connected to the zero input of the first trigger, the single input of which is connected to the single input of the second trigger and the zero input of the third trigger, the single input of which is connected to the output of the second counter and the first input of the first OR element, second Its input is connected to the signal inputs of the first block of AND elements, whose outputs are connected. To the bit inputs of the first counter, the output of which is connected to the first input of the AND element, the second input of the first OR element, and the input of the first delay element, and the bit outputs are connected. control inputs of the second block of elements AND, the signal inputs of which are connected to the bit outputs of the second counter, and outputs connected to the inputs of the second OR element, the output of which is connected to the first input of the block of the subtraction, second whose input is connected to the output of the first key, and the output is connected to the first input of the third key, the second input of which is connected to the zero output of the second trigger and the second input of the AND element, and the output is connected to the first input of the third OR element, the output of which is connected to the input of the second counter, and the second input is connected to the output of the second key, and the output of the second delay element is connected to the zero input of the second trigger. Sources of inLormotia taken into account during the examination 1. USSR author's certificate No., cl. G 01 R 23/10, 1975. 2.Karpov R.G. Analog-digital logometer. - Automation and computing technology, 197, No. 3, p. 91-33, fig. 1 (prototype).