SU1553990A1 - Functional generator - Google Patents

Abstract

The invention relates to analog computing used in the reproduction of various complex functional dependencies in automatic control systems. The aim of the invention is to expand the class of generated functions. The generator contains a start input, a pulse generator with a controlled duration, a sawtooth voltage generator, analog switches, large-scale resistors, tuning resistors, inputs for setting the positive and negative reference voltages respectively, operational amplifier, output, control unit, delay elements, keys, additional large-scale resistor, switch and tuning resistor, generator stop input. Achieving this goal is ensured by introducing into the generator a control unit, N delay elements, keys, additional scale and tuning resistors, and new connections between the elements. 3 il.

Description

The invention relates to analog computing and can be used in reproducing various complex functional dependencies in automatic control systems, as well as in medical technology, for generating reference signals, such as electrocardiograms or encephalograms.

The purpose of the invention is an extension of the class of generated Functions.

Fig, 1 shows a diagram of a functional generator; in fig. 2 is a control block diagram; in fig. Figure 3 shows timing diagrams for the generator operation.

The functional generator (Fig. 1) contains an input of 1 start, a generator of 2 pulses with a controlled duration, a generator 3 sawtooth voltage, analog switches, –– scaling resistors) tuning resistors, inputs 7 and 8 setting the positive and negative reference voltages respectively , output operational amplifier 9, output 10 of the function generator, control block 11 control, delay elements, keys 13 13p additional scale resistor 1, additional key 15 and tuning reznesl

Od

g

torus 16, stop 17, connected by the above scheme.

The control unit (Fig. 2) is made in the form of the first element 18 OR, the formers 19 and 20 short pulses, respectively, on the front and fall of the input signal, the second element OR 21, the trigger 22 and the delay elements.

Functional generator operates as follows.

A preliminary plot is made of the function by which the desired signal is described, and a piecewise linear approximation of this graph is carried out, taking into account the permissible reproduction error. For example, it is necessary to generate a signal of a normal electrocardiogram shown in FIG. For (the waveform in this case is known). The signal is divided into sections t ,, -t, Q. The number of received sections determines the number of generator outputs 2 pulses. In general, the number of generator outputs 2 pulses can be larger. Then, when the Formation of the required signal is completed, a short pulse is applied to the generator stop input. Next, the thresholds of the first ten threshold elements (not shown) of the generator 2 pulses are adjusted so that the duration of the pulses at the outputs 1-10 of the generator 2 pulses are respectively equal.

Then, resistors 6-610 and 16 are tuned so that the generator output is voltage across each section, the amplitude of which is equal to the ordinate value at the starting point of the corresponding; plot. Formed stepped

th kp, seventh m and nin

H q and to

15

0 5 o

35

40

the lot switches are connected to a non-inverting input, and the outputs of the second h, fourth Q4, sixth Q6 and ten that Q10 analog switches are connected to the inverting input of the output operational amplifier g. Coefficients P; the transmissions through the corresponding inputs (analog switch output - operational amplifier input) of the output operational amplifier 9 are determined taking into account the slope K; increasing the function in the corresponding area and taking into account the steepness S of the rising voltage of the generator 3 sawtooth voltage.

K steepness; the increment of the function in the corresponding area is determined by the ratio of the difference between the values of the ordinates at the end points of the area and the value of the duration of this area.

The steepness S of the voltage increase at the output of the generator 3 of the saw-tooth voltage is selected taking into account the dynamic range of operation of the functional generator, i.e. for any value of time t, the condition:

) - U.

where V (t) is the value of the approximated function at the time instant c;

UMCJKC maximally possible voltage amplitude at the generator output. Then

R.: to ;.

s

If the maximum voltage value of the generator 3 sawtooth voltage is equal to the maximum value

The voltage is shown in FIG. 3 and 45 lines of the constructed curve, then the fifth and sixth

the plots must be divided each into two plots at the points of transition of the value of the function through zero (see Fig. 3).

hovei line.

Further, taking into account the sign of the derivative of each section, the outputs of the analogue switches h are connected; through the scale resistors 5 to the inputs of the output operational amplifier 9 according to the following rule with a positive sign to the non-inverting input., with a negative sign to the inverting input. Moreover, the outputs of analog switches C, (Corresponding to the horizontal sections, are not connected. For the case under consideration, the outputs of the first h, n of the built-up curve, then the fifth and sixth

the plots must be divided each into two plots at the points of transition of the value of the function through zero (see Fig. 3).

After preliminary preparation, the generator is reset to the initial state by applying a short pulse to the device stop input 17. At the same time, at the outputs 1-p of the pulse generator 2 and at the output of the delay element 26 of the control unit 11, zero voltage levels are set, and at the output of the second OR element of the control unit 11, the unit level by which the sawtooth voltage generator 3 is kept in its initial, zero state nii (see fig. 3). With the arrival of the start pulse at input 1, the first output of the pulse generator 2 and the output of the delay element 26 of the control unit 11 are set to single voltage levels, and the output of the second OR element 21 is zero voltage, thereby allowing the generator 3 sawtooth wives After a time determined by the delay element 12 ,, the operation of the analog switch is allowed (keys 1-3 1-3 and 15. At the same time, the inverting input of the output operational amplifier 9 receives the linearly increasing voltage of the generator 3 and the voltage level from the output of the adder on tuning resistors 64-6h and 16, which are added together, and a signal corresponding to the first section is formed at the generator output 10. (When Fig. 1), when the voltage at the generator output 3 reaches the threshold value of the first element of the generator 2, An identical voltage level is generated only at the second output of the generator 2, which ensures that the sawtooth voltage is supplied from the output of the generator 3 through the next open analog switch k to the input of the operational amplifier 9- Synchronism of the beginning of the formation of the sawtooth-35 tori (after reset) and the opening of the next analog switch; it is provided with elements

de trigger, four delay elements, two short pulse formers, the first OR element having n / 2 inputs connected to odd12- delay.

Next, the generator operation process is repeated. The signals at the outputs of the generators 2 and 3 and the control unit 11 are shown in FIG. 3. After the formation of the tenth section has been completed, a short pulse arrives at the generator 17 inlet. A signal from the tenth output of generator 2 can be used to form it (the formation circuit in Fig. 1 is not shown). The generator is transferred to the initial zero state and is ready for the next cycle of testing a given signal, by a short start pulse.

Claims (1)

Invention Formula Functional generator, containing a pulse generator with controlled duration with n outputs, input which start is the input of the start-up, start-up of the functional generator, sawtooth voltage generator, the output of which is connected to the control input of the pulse generator with controllable duration, n analog switches, n scale resistors, n tuning resistors, the first outputs of which are combined, positive buses and a negative reference voltage and an output operational amplifier, the output of which is the output of a function generator, 5 from that, in order to expand the class of generated Functions, an additional large-scale resistor, n delay elements, a control unit, are added to it: A key, an additional tuning resistor, n keys, the information inputs of which are connected to the bus of a positive reference voltage, and the outputs are connected to the second terminals of the co5 corresponding tuning resistors , a series-connected additional key and an additional tuning resistor, the free terminal of which is connected to the combined terminals tuning resistors, the control unit is configured in vi- de trigger, four delay elements, two short pulse formers, the first OR element with p / 2 inputs connected to odd outputs of the pulse generator with controlled duration, and the second OR element, the first and second inputs of which through the first and second short pulse shapers connected to the output of the first element OR, the third input through the first delay element to the forward trigger output, and the output to the trigger input of the sawtooth generator of the function generator, setting inputs s Trigger control unit via the second and third delay elements are respectively connected to the inputs of the stop and start of the pulse generator with a controlled duration, and the counting-1 input of the trigger of the control unit is connected to the inverse p-, m output of the pulse generator with a controlled duration, the inverse output of the trigger 1 FIG. 2 Outputs element 10, and one