SU1262742A1 - Digital generator of sine oscillations with variable frequency - Google Patents

Abstract

The invention can be used in communication systems with frequency-manipulated signals. The purpose of the invention is to increase the noise immunity of the device. The shaper contains the characteristic frequency shaper 1, the manipulator 1 and the digital-analog generator 7. The introduction of the pulse frequency into the divider 3, the characteristic 4 shaper of the manipulator 5, the synchronizer 6 and their connection with the device elements eliminate temporal dominance and eliminate the loss of orthogonality of symbols during the formation of frequency-manipulated oscillations without phase break. 3 il. with s

Description

The invention relates to a pulse technique and may find application in communication systems with frequency-manipulated signals.

The purpose of the invention is to increase the noise immunity by eliminating temporal predominance and eliminating the loss of orthogonality of the symbols when generating frequency-manipulated oscillations without phase discontinuity. YU

In FIG. 1 shows a block diagram of a device) in FIG. 2 is an example implementation of the device, 'in FIG. 3 timing diagrams explaining the operation of the device. fifteen

The device comprises a first driver 1 characteristic frequencies, a first manipulator 2, a pulse frequency divider 3, a second 20 driver 4 characteristic frequencies, a second manipulator 5, a synchronizer 6 and a digital-analog generator 7.

The outputs of the first and second shapers 1 and 4 are connected respectively to the information inputs of the first and second manipulators 2 and 5, and the input of the first shaper 1 is a clock input of the device, the input of the divider 3 with a division factor is connected to the output of the first manipulator 2, and the output is connected to the input of the second shaper 4, the synchronization input of the synchronizer 6 is connected to the output of the second manipulator 5, the output is connected to the control inputs of the first and second manipulators 2 and 5, and the information input is the input of the device, the input is qi analog-to-analog ^{40 of the} generator 7 is connected to the output of the first manipulator 2, and the output is the output of the device.

Shaper works as follows. ⁴³

The information signal, which is a binary parallel 1-bit code with a symbol repetition rate f j via the input bus, is fed to the information input of the synchronizer 6, which controls the operation of the first and second manipulators 2 and 5.

In this case, the number of conductors of the input and output buses of the synchronizer is determined by the number of bits of the code, which depends on the number of frequencies generated at the output of the device, i.e. from the base of the code, and is determined by the formula ¹ 1 = log _? a. ·

The input of the first driver 1 from the clock input receives pulses with a clock frequency f _T. At the output of the former 1, sequences of pulses are formed with repetition rates {f _t / N ₍ }, where (i = 0, ..., j, ..., a-1), which are supplied to the information inputs of the first manipulator 2. Nj / frequency divisions are determined by the required values of the average (carrier) frequency and modulation index of the generated FM signal and are found by the formula a-1

Ki = 0

to.

J j = 0,1,. , a-g.

i - 0,1 ,. . . , j, .., a-1, K = n + jm d ^J о where n, m = 1,2, ..., are given positive numbers.

At the control input of the manipulator receives a control signal having about the state. Each state j (j = 0, ..., a-1) of this signal corresponds to the pulse repetition rate f, = = f _8x / N _d = f _t / N at the output of the manipulator 2. ; (j = 0, ..., a-1). The pulses of the selected repetition rate f / Nj from the output of the manipulator 2 are fed to the inputs of the digital-analog generator 7 and the pulse-frequency divider 3.

At the output of the digital-analog generator 7, a bipolar signal is formed, which is a stepwise approximation of harmonic oscillation. The frequency fj of the output signal generator 7 is associated with the pulse repetition rate at its input

2L by f j

_ £ x_

2LN ’j

where is an integer determined by the required approximation accuracy. At the output of the divider 3, pulses are formed with a repetition rate f _T / LN ·. These pulses are fed to the input of the second shaper of characteristic frequencies. 4, the output of which is obtained about sequences of pulses with frequencies | i = (0, ..., a-1), which are fed to the information inputs of the second manipulator 5.

The frequency division coefficients K of the second driver 4 correspond to the first frequency division coefficients Nj of

Κ.Ν

4 shapers 1 and the conditions a-1 = Л _о ^к , = const, j = 0, .., a-1 ¹ 5 '5

The control input to the manipulator 5 receives the same control signal as the control input to the manipulator 2. Each state j (j = 0, a-1 *) of this signal corresponds to the output of the manipulator 5, the pulse repetition rate f = ρρΐΧ = = Due to the appropriate choice of the division factors of the shapers 1 and 4, the pulse repetition rate at the output of the manipulator 5 is constant for all a states of the input information signal. Therefore, the signal of the manipulator 5 is used as a clock signal to control the synchronizer 6.

In this case, the symbol frequency is equal to the value _f = = __k_ s · N.LK. _t a-1

4 L _p i = 0 and remains constant a-1 values f _t , L, K

TO.

for given

In this case, the formation of an FM signal with a constant symbol duration T - 1 / f $ = = const is ensured, which eliminates the temporal predominance in the output signal.

In the formation of the o-main FM- ⁴ ® signal, the non-clocking frequency is determined by the expression f = _ ^K J h 2L ί = 0 a-ϊ aP _p K.

ι = 0 ’a-1

Q5 ((n ₊ .L__

2L ^a p ¹ ί = 0 and the difference in the average frequencies by the formula _ofj (j., _J.

Ά

The normalized modulation index is determined by the expression a-1

D = if. (j +1) · Τ = -Mm /. ⁿ K) xj ^J 2L 1 = 0 i a-1 x α.Πθ K _i / f _T = 5, m = 1,2, ...).

Since the value of m is an integer, the formation of an FM signal with orthogonal symbols is ensured. The result is an increase in noise immunity of the generated FM signal.

The main nodes of the device can be performed in various ways. Shapers 1 and 4 of the characteristic frequencies can consist of frequency dividers & with division factors respectively N _o , ... , N ₄ , ..., N _a ., And K _o ,. .., Kj, ..., Κ _α _ ₁ : Manipulators 2 and / can be multiplexors, the number of control inputs of which is 1 = log ₂ a, and information inputs - a. Synchronizer 6 may consist of 1 = log ^ a D-flip-flops, at the inputs D of which 1 information leads the input signal, and at the inputs C-signal synchronization from the output of the manipulator 5.

In FIG. 2 shows an example of a specific embodiment of the device for a = 2, t = 1, and in FIG. 3 is a timing diagram explaining its operation.

In FIG. 2 shows a pulse divider 8. by (n + 1), divider 9 of the pulse frequency by n, inverter 10, elements 11 and 12, element OR 13, D-trigger 14, divider 15 pulse frequencies by n, divider 16 pulse frequencies by (n + 1), inverter 17, elements AND 18 and 19, element OR 20.

The device operates as follows.

The information signal (Fig. 3a), which is a binary single-bit code, is fed to the input of the D-flip-flop 14. The signal from the output of the synchronizer 6 controls the operation of the first and second manipulators 2 and 5. The clock signal f is received at the input of the first driver 1 (Fig. 36). At the outputs of the frequency dividers 8 and 9, the frequencies f _T / (n + 1) and f ^ / n (FIG. 3S) are formed respectively, which are supplied to the elements And 11 and 12 of the first manipulator 2, respectively. Upon receipt of the information input to the manipulator 2 of the manipulator A signal of positive polarity opens the And 12 element and pulses with a frequency f = f _r / n come from the output of the OR 13 element. When a signal of negative polarity arrives at the output of the manipulator 2 through open pulses from element And 11, they arrive at a frequency f = --7. The output ° n + 1 of the divider 3 (Fig. 3g) is connected to the inputs of the frequency divider 15 by η and by (n + 1) of the second driver 4.15

Depending on the frequency f _T / L (n + 1) or f / Ln at the input of the second driver 4 and at the output of the divider 15, the frequencies f _T / Ln (n + 1) or f _T / Ln ^{2 are formed} , and at the output of the divider 16 -20 frequencies f ₇ / Ln (n + 1) or f _T / L (n + 1) ² , which are supplied respectively to the elements And 18 and 19. When an information signal of positive polarity is received, the element 25 And 19 opens and from the output of the OR element 20, pulses with a frequency f _T / Ln (n + 1) arrive, since at this moment in time, pulses with a frequency f _T / nL arrive at the input of the second manipulator 5. With jq of negative polarity of the input information signal, the output of the second manipulator 5 also receives pulses with a frequency f _T / Ln (n + 1), since the input of the second shaper 4 ₃₅ receives pulses with a frequency f _T / L (n + 1) ' Thus, the sync input of the trigger 14 of the synchronizer 6 always receives pulses of constant frequency _f = ___k_

Ln (n + 1) (Fig. 3d). Since the division coefficient of the digital-analog reft 'of the speaker 7 is chosen equal to 2L, a signal of frequency r = --4— is formed at its output. _λ or r = -

2L (n + 1) ’2Ln (Fig. Ze). Moreover, af = f, - f 'o = _ £ x_ _ ___ ____ £ x

2Ln 2L (n + 1) 2Ln (n + 1) S = 1 / 2T.

Thus, the digital driver generates a frequency-manipulated signal with symbols of constant duration and continuous phase, which ensures orthogonality of the symbols and high noise immunity.

Claims (2)

The invention relates to a pulse technique and may find application in communication systems with frequency-manipulated signals. The purpose of the invention is to improve noise immunity by eliminating temporal dominance and eliminating the loss of orthogonality of symbols when generating frequency-manipulated oscillations without phase discontinuity. FIG. 1 shows a block diagram of the device i in FIG. 2 shows an example of the implementation of the device; FIG. 3 timing diagrams explaining the operation of the device. The device contains the first driver 1 of the characteristic frequencies, the first manipulator 2, the divider 3 times the pulse following, the second driver 4 of the characteristic frequencies, the second manipulator 5, the ejector 6 and the digital-analog generator 7. The transducers of the first and second drivers 1 and 4 are connected respectively to the information the inputs of the first and second manipulators 2 and 5, and the input of the first driver 1 is the clock input of the device, the input of the divider 3 with the division factor is connected to the output of the first manipulator 2) and the output The d is connected to the input of the second generator 4, the synchronous input of the synchronizer 6 is connected to the output of the second manipulator 5, the output is connected to the control inputs of the first and second manipulators 2 and 5, and the information input is the input of the device, the input of the digital-analog generator 7 is connected to the output of the first arm 2, and the output is the output of the device. The shaper works as follows. The information signal, which is a binary parallel 1-bit code with a symbol frequency f J on the input bus, is fed to the information input of the synchronizer 6, which controls the operation of the first and second manipulators 2 and 5. At the same time, the number of conductors 1 is input and the output bus of the synchronizer is determined by the number of code bits, which depends on the number and of the frequencies generated at the device output, i.e. from the base of the code, and is determined by the formula 1. At the input of the first imager 1 from the clock input pulses come with a clock frequency f. At the output of the imaging unit 1, a series of pulse sequences are formed with the following frequencies, where (, ..., J, ..., a-1), which are fed to the information inputs of the first manipulator 2. The coefficients N / frequency division are determined by the required nominal values of the average (carrier) frequency and modulation index of the formed FM signal and are calculated by the formula n ,, j 0,1a -1, i - 0,1, ..., j ,. ., a-1; K. К n + jm J d -о where n, m 1,2, ..., are given positive numbers. The control input of the manipulator 2 receives a control signal having a state. To each state j (, ..., a-1) of this signal corresponds at the output of the manipulator 2 the pulse frequency fn, fg, / Nj f T / Nj; (j 0, ..., a-1). The pulses of the selected f- / NJ following frequency from the output of the manipulator 2 are fed to the inputs of the digital-analog generator 7 and the divider 3 of the pulse frequency. At the output of the digital-to-analog generator 7 ph1 ::}, a two-pole signal is formed, which is a stepwise approximation of the harmonic oscillation. At the same time, the frequency f of the output generator 7 of the signal is related to the pulse frequency at its input by the ratio f, where 2L is an integer determined by the required approximation accuracy. At the output of the divider 3, pulses with a frequency of following are formed. These pulses are fed to the input of the second driver of the characteristic frequencies. 4, at the output of which receive Q sequences of pulses with {k-Shch-} i 0-. -one). frequencies that are fed to the information inputs of the second manipulator 5. The frequency division factors K of the second generator 4 correspond to the NJ coefficients of frequency division of the first generator 1 and are determined from the condition a-1 KN .Q K const,, ..., aH on the manipulator control input 5 receives the same control signal as that to the control input of the driver 2. Each state j (j O, a-1; this signal corresponds to the output of the manipulator 5 on the pulse frequency ff Thanks to the corresponding K.LN. selection of form division factors The pulses at the output of the manipulator 5 of the transmitters 1 and 4 are constant for all the states of the input information signal. Therefore, the signal of the manipulator 5 is used as a sync signal to control the synchronizer 6. At the same time, the symbol frequency is equal to f 1. f .t a-1 "L p, and remains constant for the given a-1 values f, L, .- K -. In this case, the formation of the FM signal with a constant duration of the symbols T 1 / f const is ensured, which allows eliminate the temporal dominance in the output signal. When a-the main FM signal is formed, the frequency is not pronounced, with the expression a-1 „f З -.П -Kj 2L а-1 -а, J ... (gi). 2L HW and the difference of the middle frequencies. ga.,) - jf --- --а The normalized modulation index is then determined by the expression D uf. (jH) -T § (.) XJ / L) 1 X (Pr, m 1,2, .. .) Since m is an integer, the formation of an FM signal with orthogonal symbols is ensured. As a result, the noise immunity of the formed FM signal is increased. The main components of the device can be made in various ways. The formers 1 and 4 of the characteristic frequencies may consist of frequency dividers with division factors, respectively, N. J ,. . ., K „,. ..,, ..., K,; Manipulators are 2 and can be multiplexers, the number of control inputs is 1 log a, and the information inputs are a. The synchronizer 6 may consist of 1 D-flip-flops, to the inputs D of which an information input signal is sent to 1 conductors, and to the inputs a synchronization signal C from the output of the manipulator 5. In FIG. 2 shows an example of a specific embodiment of the device for,, and FIG. 3 - time diagrams that show his work. FIG. 2 shows the divider 8 pulse frequency. on (n + t), divider 9 pulse frequency on p, inverter 10, elements 11 and 12, element OR 13, D-flip-flop 14, divider 15 pulse frequency on n, divider 16 pulse frequency on (n + 1), Inverter 17, elements AND 18 and 19, element OR 20. The device operates as follows. The information signal (Fig. 3A), which is a binary one-bit code, is fed to the input of the D-flip-flop 14. The output signal of the synchronizer 6 controls the operation of the first and second manipulator 2 and 5. The input of the first shaper 1 is a clock frequency signal f. (Fig. 36). At the outputs of dividers 8 and 9, the frequencies are formed, respectively, of the frequencies (n-H) and f (Fig. 3b), which are fed respectively to the elements 11 and 12 of the first manipulator 2. When the manipulator input 2 of the information signal of a positive polarity arrives at the control polarity, the element And 12 is turned off, and the pulse f is received from the output of the element OR 13. When a negative field signal is reached at the output of the manipulator 2 through the open element And 11, it is received by it J-I. Pulses with frequency f p + G divider 3 (Fig. 3g) are connected to the inputs of frequency divider 15 by n and 16 by (n + 1) of the second driver 4 Depending on the frequency (n + 1) Or at the input of the second driver 4 and the output of the divider 15 forms frequencies (n + 1) or, and at the output of the divider 16 frequencies (n + 1) or (), which are fed to elements 18 and 19, respectively. When the information signal of positive polarity arrives, the element 19 and pulses with a frequency of f / Ln arrive at the output of the element OR 20 (n – t such as at this moment in time to the input of the second manipulator 5 pos when the input information signal is negative, the output signal of the second manipulator 5 also receives an impulse with a frequency (n + 1), since the second shaper 4 receives impulses with a frequency (n + 1). The trigger 14 of synchronizer 6 always receives pulses of a constant frequency {„(FIG. 3). Since the coefficient 5 LnV.n + 1j is the division factor of the digital-analogue generator 7 chosen equal to 2L, a 1 / 2T signal is often generated at its output. Thus, the digital shaper forms a frequency-manipulated signal with symbols of constant duration and continuous phase, which ensures the orthogonality of symbols and high noise immunity. DETAILED DESCRIPTION OF THE INVENTION Digital variable frequency shaper comprising a series of first characteristic frequency drivers, a first manipulator and a digital-analog oscillator, the output of which is the output of a device whose clock input is the input of the first frequency characteristic generator, characterized in that, in order to increase noise immunity , a series-connected pulse frequency divider is introduced into it, the second driver is characterized frequency, the second manipulator and the synchronizer, the second input of which is the device input, and the output connected to the control inputs of the second and first manipulator, and the output of the first manipulator connected to the input of the pulse frequency divider. FIG. 2 about / ./ frjn fr / in il iiiiiiiiiii iiiiiiiiiii iliilll fr / ln fjjLfn i) I I  I fr / lnfnt fr / n iliUli fr / l-fn l) 1 I I I