SU1311009A1 - Method and apparatus for generating a number of pulse-width modulated pulse signals which are uniformly shifted with respect to phase - Google Patents

Abstract

The invention relates to a pulse technique. The purpose of the invention is to solve the dynamic and frequency ranges of the modulation. The method of forming a p a d ay of width-modulated pulse signals (SHMIS) uniformly shifted in phase is implemented in the device. To achieve the goal, the discriminator 4 overmodulation, adder 6, decipher- are entered into the device. The torus 7 and the node 5 of the allocation of modulation zones. The method includes comparing the input signal with the reference voltage (n), forming the reference H by repeatedly sequentially adding to the sawtooth H a constant H equal in magnitude to the span of the sawtooth H every time the input signal exceeds the upper boundary value of the reference H, and when the value decreases the input signal below the lower boundary value of the change in the reference H is successively reduced by a constant H, equal to the span of the sawtooth H, the formation of the result of the comparison of the input and the reference H between its various values of SHMIS and the formation of output pulsed H, presumably, their front fronts are formed successively on the front edges of the pulse-in ShMIS, and the rear fronts are sequentially formed through n ShMIS pulses along their back fronts, where n is defined as the swing ratio reference H to the span of the sawtooth Hi 2 sec. f-ly, 3 ill. with (L with: oo

Description

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The invention relates to an impulse, an advanced technique and can be used in automation devices and low-frequency key amplifiers:

The purpose of the invention is to expand the dynamic and frequency ranges of the modulation by generating N uniformly phase-shifted output pulses when using a reference signal, whose span increases in proportion to the increase in input signal

The method of forming a series of pulse-width-modulated pulse signals evenly shifted in phase involves comparing the input signal with the reference voltage, generating the reference voltage by repeatedly sequentially adding to the sawtooth voltage of constant voltage, equal in magnitude to the sawtooth voltage. when the input signal exceeds the upper limit value of the reference voltage, and when the input signal ngoke decreases, the limit value of the change in the reference voltage and it is successively reduced by a constant voltage, equal to the span of the saw-tooth voltage, the formation of the comparison of the input and reference voltages, between its boundary values of the width-modulated impulse signal and the formation of the output pulse voltages, moreover, their forward fronts form successively along the leading edges of the pulses of the modulation-modulated signal, and the falling edges - successively through n pulses of the width-modulated signal along their falling edges, where thinned as the ratio of magnitude of the reference voltage to the sawtooth sweep.

FIG. 1 shows a block diagram of a device for generating a number of pulse width modulated pulse signals uniformly shifted in phase; figure 2 - timing charts of his work; fig.Z - examples of the implementation of individual units of the device,

A device for forming a series of broad-band data from P1X signals contains a generator of 1 clock pulses, a generator of 2 saw-tooth voltages, a comparator 3, / discriminator 4 non-modulation, node 5

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special items ;; the modules p; i, the adder 6, the decoder 7 and the ring register 8 shift, while the output of the generator 1 tact pulses connected to the input

generator 2 sawtooth voltage and the first input of the discriminator 4 overmodulation, the second input of which is connected to the output of the comparator 3, the input of the ring register 8 shift and

the first input of the decoder 7, the second inputs to the mountain are connected to the outputs of the circular shift register 8, the outputs of the device output tons, and the third inputs of the outputs of the node 5 of the allocation of modulation zones and the inputs of the adder 65 post: the ice entrance is connected to the generator output 2 pilos; a common voltage, and an exit - with the first input of the comparator 3, the second

 which is connected to the input spike, and the outputs. of the discriminator 4 are connected to the inputs of the node 5 of the allocation of modulation zones.

five

0

five

0

A clock pulse generator 1 is designed to form a pulse train of the mea.dr type; which is converted by a sawtooth voltage generator 2 in a linearly used, -1 symmetrical signal, Up, Generator, to a saw voltage voltage 2, can be performed on an operational amplifier swept by capacitive feedback (Fig. 3).

Comparator) 3 sluzhit / dl for generating a liHH signal with PWM (FIG. 2.2) based on the result of comparing the input signal I gj with a reference; m voltage U (fig 2.1) g; stating {m at its input through the adder B.

Discriminator 4 overmodules {and a number to form the first V; and l. of the second V,., (Fig.2.3, 2.4) signals, ha; eakterizuyuE; their overmodulation signal with ShZH1. When a signal is modulated with a maximum scale, the sawtooth voltage corresponds to an impulse of a comparator, which leads to an increase in the first impulse signal (Fig. 2, 3)) which characterizes the need to increase the support: -U1 about ex. wives If the minimum value of the change in the reference voltage 1-1II corresponds to a pause at the output of KOMTiapaTOpa 3, then at the output of the discriminator i, a second pulse signal is formed (Fig 2.4) 5 which characterizes the dog-bhoggema of the decrease in the reference voltage. Dis: criminator 4 peremodul 313

This parameter can be executed (Fig. 3) on the delay element for the interval T Т T (t OjOlT) and the logical elements.

The modulation zone allocation device is designed to sequentially form unit potentials at the N-1 output (Figs 2.5-2.7) with an increase in the reference voltage (formation of the first pulse signal of Fig.2.3 by discriminator 4). When the reference voltage decreases (forming a pulse signal of Fig. 2.4), the output busses of the modulation zone allocation section 5 are successively nullified (Fig. 2.5-2.7). These voltages are fed to the inputs of the adder 6, the output sawtooth voltage of which varies from V (p-1) to V,

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the boundary values of the reference stress change.

Thus, in the proposed device for any input level

from the signal, the selection of the modulation area for which the

condition (n-1) V: „- n.

to

)five

For the set modulation zone, the output voltages of the modulation zone allocation section 5, arriving at the third inputs of the decoder 7, ensure the formation of the duration of the output pulses in accordance with the expression T T (n-1) + (T. The leading front of the output pulses ( Figures 2.12-2.15) are alternately formed, which is provided by the output voltages of the ring shift register 8, which are connected to the second inputs of the decoder 7.

Consequently, the device ensures linearity of the modulation characteristic, i.e. for each of

channels, the expression / N1 Ugx / N is executed.

P.

The node 5 of the allocation of the modulation zones can be performed (Fig. 3) on the RS flip-flop, (N-1) D-flip-flops and logical

elements.

The circular shift register 8 (FIG. 3 / serves to alternately allocate N 25 periods (FIG. 2.8-2.11) of the PWM signal (FIG. 2.2). The output signals of the register 8, fed to the second control inputs of the decoder 7, provide alternating formation of leading edges it is positive, in the device providing voltages (Fig. 12-2-2.15) their uniform phase shift is shown, to the leading edge of the PWM signal, which results in an increase in the total (Fig. 2.2).

Output voltages of node 5, post- „/ o., H

. 35 current range of the device (Fig.2.16). PA to the second control inputs decrypt- "

Since the device uses

orator 7, change its duration

output pulses (Fig.2.2-2.15) and the formation of the leading edge of the output pulses occurs through n pulses of the signal with PWM along their falling edge. A possible implementation of the decoder 7 is shown in FIG.

The device works as follows.

The input signal Ug is fed to the input of the comparator 3 (Fig. 2.1), where it is compared with a sawtooth voltage. This allows the use of the proposed device in class D multichannel amplifiers. Because the leading edges of the output pulsed voltages are generated N times, as a result as frequency increases 40

45

Since in

there is no comparison with only one sawtooth voltage; there is no distortion of the output signal due to non-identical channels. This allows the use of the proposed device to reduce output distortion in multichannel class D amplifiers, and a change in the values of the reference voltage along with an increase in the input signal allows the dynamic range of the signal to be expanded to be expanded.

cue and "(t), the boundary values of which are set from

50

Vn (n-) to Vn-n, where, 2,3 ...

When Ug exceeds the set limits, the discriminator 4 generates the first (Fig. 2.3) or second (Fig. 2.4) pulse signals, which lead it, respectively, to the switching of the modulation zone separation unit 5, the output voltages of which (Fig. 6) cause increase or decrease

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the boundary values of the change in the reference voltage.

Thus, in the proposed device for any input level

from the signal, the selection of the modulation area for which the

condition (n-1) V: „- n.

For the set modulation zone, the output voltages of the modulation zone allocation section 5, arriving at the third inputs of the decoder 7, ensure the formation of the duration of the output pulses in accordance with the expression T T (n-1) + (H. The leading edge of the output pulses (FIG. .2.12-2.155) is formed alternately, which is provided by the output voltages of the ring 8 shift register, which are supplied to the second inputs of the decoder 7.

Therefore, the modulation characteristic is linear in the device, i.e. for each of

channels, the expression / N1 Ugx / N is executed.

In the device, their phase shift is ensured, which results in an increase in the total

This allows using the proposed device in class D multichannel amplifiers. Since the leading edges of the output pulsed voltages are formed sequentially, the device ensures their uniform phase shift, which results in an increase in the total

 „„ / О., H

the switching frequency is N times, as a result of which the frequency 35 range of the device increases (Fig. 2.16). „

Since the device uses

40

45

Since in

Comparison with only one sawtooth voltage, output signal distortion due to non-identical channels. This allows the use of the proposed device to reduce distortion of the output signal in multichannel amplifiers of class D, and a change in the values of the reference voltage along with an increase in the input signal allows the dynamic range of the converted signal to be expanded.

Claims (2)

Claim 1. A method of forming a number of latitude-modulated pulse signals uniformly shifted in phase, including the formation of a reference voltage, comparing the input signal with a reference voltage, forming the result of a comparison of the width-modulated pulse signal, generating N output pulse on 513 , in order to expand the dynamic and frequency ranges of the modulation, the input signal is additionally compared with the boundary values of the changes in the reference voltage, which are formed by repeatedly sequentially adding a constant voltage to the sawtooth voltage equal to the magnitude of the sawtooth voltage voltage, any time when the input signal exceeds the upper limit value of the reference voltage, and when the input signal decreases below the lower limit value and By changing the reference voltage, it is successively reduced by a constant voltage equal to the span of the sawtooth voltage while the leading edges of the output pulse voltages are sequentially formed along the leading edges of the pulses of the width-modulated signal. And the rear edges of the output pulse voltages are sequentially formed through n pulses of a pulse-modulated signal along their falling edges, where n is defined as the ratio of the magnitude of the reference voltage to the range of the sawtooth. 2. The device for the formation of p -. W. Pulse Width Modulated 96 signals uniformly shifted in phase, containing a clock pulse generator, an annular shift register, a sawtooth voltage generator and a comparator, the first input of which is connected to the input bus, characterized in that, in order to expand the dynamic frequency modulation ranges, a discriminator is introduced into it overmodulation3 an adder, a decoder, and a modulation zone allocation node, the clock pulse output being connected to the generator input the sawtooth voltage and the first input of the overmodulation discriminator, the second input is connected to the comparator output, to the input of the ring shift register and the first input of the decoding unit, the outputs of which are connected to the output buses of the device, the second inputs to the outputs of the ring register shift and a third the inputs are with the outputs of the node of the allocation of modulation zones and the inputs of the adder, the last input of which is connected to the output of the saw-tooth generator, and the output is connected to the second input of the comparator, while the outputs of the discriminator overmodulations are connected to the inputs of the mute zone release node. (pue.2