Converter for converting periodic signal to frequency and period

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to pulse engineering and can be used in automatic control systems, measuring devices, controlled phase changers and in designing multi-phase generators. The device comprises comparators, monovibrators, a sampling-storage device, a dc voltage source, a switch, resistors, a capacitor, an operational amplifier and a signal former, proportional to the frequency of the input signal.

EFFECT: obtaining two signals with high linearity at outputs of the converter, one of which varies in proportion to the period and the other in proportion to the frequency of the input signal, with amplitude and frequency which vary in a wide range.

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The invention relates to a pulse technique and can be used in automatic control systems, measuring devices, managed phasers, as well as when building a multi-phase generators.

It is known device [1], containing the source of the harmonic signal and the RC-circuit with the properties of real differentiating element with transfer function H(s)=[τ·s/(τ·s+1)], where τ=R·C time constant circuit; R is the resistance of the resistor and C is the capacitance of the capacitor; s is a complex variable.

The device allows you to receive only one signal, depending on the frequency of the input source. However, the voltage at the output of the circuit depends not only on the frequency f and amplitude A of the input signal, which is a significant drawback of this Converter. In addition, when the frequency f in a wide range inevitably there is additional uncertainty associated with the imperfection differentiating chain, since the transmission coefficient of the real differentiating link$$H_R\left(f\right)=2\pi ft/\sqrt{1+{\left(2\pi ft\right)}^2}$$differs from the coefficient of transmission is ideal differentiating level H ₁(f)=2πfτ. The disadvantages include the inability to work of the transducer from the source form of the signal other than the harmonic.

The closest device to the claimed invention, the set of essential characteristics is adopted for the prototype Converter period-voltage [2], which contains a two-channel storage device, a comparator, an inverter, a comparison circuit, a lowpass filter, two keys, storage capacity, repeater, the constant voltage source and three resistors, and the first input of the first storage device is connected to the output of the comparator and the input of the inverter, the output of which is connected to the first input of the second storage device, the first and second outputs of which are connected respectively with the first and second inputs of the second key, the output of which is connected to the input of the repeater, the output of which is connected to the inverter output, the input connected to the comparator input, the first and second outputs of the first storage device are connected respectively with the first and second inputs of the first key, the output of which is connected to the input of the repeater, the first input schema matching is connected to the first output of the first storage device, to the first output of the second storage device connected to the second input of the comparison circuit, the output is d which is connected to the input of the lowpass filter, between the output of the constant voltage source and a second input of the first storage device includes a first resistor, a second resistor connected between the output of the constant voltage source and the second input of the second storage device, a third resistor connected between the output of the lowpass filter and the second input of the second storage device, and an accumulation tank connected between the common bus and the input of the repeater.

While the first and second storage devices performed similarly, each of which includes a chain of serially connected two differentiation, sawtooth generator and a sample-hold first input connected to the output of the sawtooth generator and the second input with the second output of the first storage device and the first output of the first differentiator.

The device is quite complex and allows you to receive only one signal, proportional to the period of the input source.

The problem to which the invention is directed, is to expand the functionality of the device.

The technical result achieved by carrying out the invention, is to expand functionality by receiving outputs of the Converter intermittent the signal in the frequency and period of the two signals with high linearity one of which changes in proportion to the period, and the other proportional to the frequency of the input signal is changing in a wide range of amplitude and frequency.

This technical result in the implementation of the invention is achieved in that in the Converter of the periodic signal in the frequency and the period containing the comparator, the first and second adenovirally, the device of the sample-hold a constant voltage source, the key, the first and second resistors and a capacitor, and inverting and non-inverting inputs of the comparator are connected respectively with the common bus and the inverter input periodic signal in the frequency and the period between the comparator output and control input key is enabled, the first one-shot, the output of the sample-hold is connected to the inverter output periodic signal in the frequency and time period to the negative terminal of the DC voltage connected in series connected first and second resistors, inputs of the second comparator, operational amplifier and shaper signal proportional to the frequency of the input signal, while the non-inverting and inverting inputs of an operational amplifier are respectively connected to the shared bus and to the common connection point of the first and second resistors between the output and invert the ith input of the operational amplifier switched capacitor the normally open contact of the key is included between the free output of the second resistor and the output of the operational amplifier, the output of which is connected to the first input of the sample-hold, the second input is connected to the output of the second one-shot, the input connected to the output of the second comparator non-inverting and inverting inputs of which are connected respectively with the common bus and the inverter input periodic signal in the frequency and period, the output of which is connected to the input of the shaper signal proportional to the frequency of the input signal, the output of which is connected to the second inverter output periodic signal in the frequency and period.

Shaper signal proportional to the frequency of the input signal, is made of the divider of the delay block and the reference voltage, the negative clamp which is connected to a shared bus, and to its positive terminal connected to the input of the delay unit, the output of which is connected to the first input of the divider, a second input and output of which are connected respectively with the input and output of the shaper signal proportional to the frequency of the input signal.

Conducted by the applicant's analysis of the prior art, including searching by the patent and scientific and technical information sources, has allowed to establish that the applicant had not discovered analogue, x is rasterizers signs, identical with all the essential features of the claimed invention. Therefore, the claimed invention meets the condition of "novelty."

Introduction in the proposed Converter periodic signal in the frequency and period of the second comparator, operational amplifier and shaper signal proportional to the frequency of the input signal, and a driver signal that is proportional to the frequency of the input signal, and the organization of new connections between the functional elements allowed to get on the outputs of the inverter periodic signal in the frequency and period signals with high linearity proportional to the period and the frequency of the input source, changing its parameters in a wide range.

The invention is illustrated the block diagram of the Converter of the periodic signal in the frequency and period are depicted in figure 1, and charts explaining the operation principle of the Converter of the periodic signal in the frequency and period - 2.

The Converter of the periodic signal in the frequency and period contains two comparator 1 and 10, two one-shot 2 and 3, the device sample-hold 4, shaper signal proportional to the frequency of the input signal 12, the operational amplifier 11, the constant voltage source 5, the key 6, the first 7 and second 8 resistors and the capacitor 9, and the entrance ol the formers periodic signal in the frequency and period connected with reinvestiruet the input of the comparator 1 and the inverting input of the second comparator 10, between the comparator output 1 and control input key 6 includes a first one-shot 2, the second one-shot 3 included between the output of the second comparator 10 and the second input of the sample-hold 4, the output of which is connected to the inverter output periodic signal in the frequency and period, and with the input of the shaper signal proportional to the frequency of the input signal 12, the output of which is connected to the second inverter output periodic signal in the frequency and time period to the negative terminal of the DC voltage source 5 is connected in series connected first 7 and second 8 resistors to a common connection point which is connected inverting input of the operational amplifier 11 between the output and inverting input switched capacitor 9, the normally open contact of the key 6 is included between the free output of the second resistor 8 and the output of the operational amplifier 11, the output of which is connected to the first input of the sample-hold 4, while the inverting input of the comparator 1, a non-inverting input of the second comparator 10 and the positive clamp of the DC voltage source 5 is connected to a common bus.

This shaper signal proportional to the frequency of the input signal 12, made of divider 13, the delay unit 14 and the reference-voltage source 15, neg the AUX clamp which is connected to a common bus, and to its positive terminal connected to the input of the delay unit 14, the output of which is connected to the first input of the divider 13, the second input and the output of which is connected respectively with the input and output of the shaper signal proportional to the frequency of the input signal 12.

The Converter of the periodic signal in the frequency and the period is as follows.

On the non-inverting input of the first 1 and the inverting input of the second 10 Comparators receives a periodic signal, for example (figure 2) pure sine wave

where A₀the amplitude of the signal, N₀(t); x=ωt - current value of the angle, expressed in radians.

At the output of the comparator 1, a signal is generated M₁(t) of a rectangular shape at the input of the first one-shot 2, and the output of the second comparator 10, a signal is generated M₂(t) of a rectangular shape at the input of the second one-shot 3.

The output of one-shot 2 is formed by a sequence of narrow pulses V₁(t), attached to the leading edge of the signal M₁(t), and output the one-shot 3 is formed by a sequence of narrow pulses V₂(t), attached to the leading edge of the signal M₂(t).

Because the signals M₁(t) and M₂(t) shifted in phase by 180 degrees, the pulse sequence V₁(t) and V₂(t) also Bud is t joined to each other at 180 degrees (figure 2).

Operational amplifier 11, the first resistor 7 and the capacitor 9 form an integrator with transfer function

where τ=R·C time constant of the phase shifter 1; R is the resistance of resistor 7; C is the capacitance of the capacitor 9; s is a complex variable.

The second resistor 8 is used to limit the magnitude of the discharge current of the capacitor 9, which occurs with the closure of the key 6.

The pulses from the output of the first one-shot 2 go to the control input of the key 6, and the pulses from the output of the second one-shot 3 - for the second input of the sample-and-hold.

When you open the key 6, the capacitor 9 is charged linearly from the constant voltage source 5 through the resistor 7. Since the operational amplifier 11 is inverting, the output of the operational amplifier 11, that is, at the output of the integrator is formed by linearly increasing voltage L positive polarity (figure 2). The slew rate and maximum level of this voltage will depend on the time constant of the integrator τ and the voltage E₁at the input of the integrator from the constant voltage source 5.

Remembering voltage L occurs at the time of filing the gate pulse V₂(t)supplied to the second input of the sample-hold 4. The choice of the time constant integrate the and and the voltage will allow at the moment of entering the gate pulse to obtain (2) at the output of the sample-hold 4 signal N ₁proportional to the period T of the input signal, N₀(t):

where k₁is the coefficient of proportionality.

The reset of the integrator, i.e. the discharge of the capacitor 9, occurs at the time of filing a narrow pulse V₁(t) the control input key 6. At this point there is a rapid discharge of the capacitor 9 to zero, with the magnitude of the discharge current is limited by the size of the small resistance of the resistor 8.

Then the process of charge-discharge capacitor 9, i.e. the formation of a linearly varying voltage, is repeated (figure 2).

The formation of the second inverter output signal N₂(t), proportional to the frequency f of the input signal, N₀(t), occurs in the shaper signal proportional to the frequency of the input signal 12, as follows.

At the first input of the divider 13 from the reference-voltage source 15 through the delay unit 14 is energized E₀=1, and to the second input of the divider 13 is energized N₁from the first inverter output periodic signal in the frequency and period.

As a result of performing mathematical operations division at the output of divider 13, that is, the second inverter output periodic signal in the frequency and period, a signal is generated proportional to the frequency f of the input signal, N₀(t)

where k₂=m/k₁the proportionality constant, m is the scale factor of the divider 13; f=1/T.

The delay unit 14 is required for proper operation of the divider 13, because it excludes performing a mathematical operation of dividing one value (voltage E₀) to another (the voltage of the N₁), with the initial moment of time (at start) to zero. The delay τ₂(figure 2)generated by the delay unit 14, should exceed the value of the time τ₁i.e. τ₂>τ₁.

The Converter of the periodic signal in the frequency and period can work with periodic signals (sinusoidal, triangular, trapezoidal, rectangular) shape, and may be performed in the integrated design, which is an advantage of the present invention. Output characteristics, i.e. according to the generated output signals from the parameters (period and frequency of the input signal, linear in a wide range of their variation, which is also an advantage of the present invention.

Sources of information

1. Kuznetsov E. Two analog frequency meter. The magazine "Radio", 2009, No. 7, p.74 - 1.

2. RF patent №2030108, H03K 9/06. Sukachev YU.N., Chalov E.I. Converter period - voltage. 1995

1. The Converter of the periodic signal in the frequency and the period containing comparator, the first and second adenovirally, the device of the sample-hold a constant voltage source, the key, the first and second resistors and a capacitor, and inverting and non-inverting inputs of the comparator are connected respectively with the common bus and the input of the Converter, between the comparator output and control input key is enabled, the first one-shot, the output of the sample-hold is connected to the inverter output periodic signal in the frequency and time period to the negative terminal of the constant voltage source connected in series connected first and second resistors, characterized in that it additionally introduced a second comparator, operational amplifier and shaper signal proportional to the frequency input, with noninverting and inverting inputs of an operational amplifier are respectively connected to the shared bus and to the common connection point of the first and second resistors between the output and inverting input of the operational amplifier switched capacitor, normally open contact key included between the free output of the second resistor and the output of the operational amplifier, the output of which is connected to the first input of the sample-hold, the second input is connected to the output of the second one-shot, the input connected to the output in the showing of the comparator, non-inverting and inverting inputs of which are connected respectively with the common bus and the inverter input periodic signal in the frequency and period, the output of which is connected to the input of the shaper signal proportional to the frequency of the input signal, the output of which is connected to the second inverter output periodic signal in the frequency and period.

2. The Converter of the periodic signal in the frequency and period of claim 1, wherein the driver signal is proportional to the frequency of the input signal, is made of the divider of the delay block and the reference voltage, the negative clamp which is connected to a shared bus, and to its positive terminal connected to the input of the delay unit, the output of which is connected to the first input of the divider, a second input and output of which are connected respectively with the input and output of the shaper signal proportional to the frequency of the input signal.