HU195376B - Circuit arrangement for generating equidistant frequencies - Google Patents

Abstract

The present invention relates to a switching arrangement for generating frequencies at equal distances, the oscillator (1) of modulators (1), at least one frequency divider (2), and band filters (5 / 1.5 / 2, ..) of the frequency discriminator stabilized voltage conductors. .5 / 6). The circuit arrangement according to the invention is that the frequency divider (2) has an average frequency (fc) service output between the maximum and minimum frequencies to be produced, or an additional frequency divider (6) connected to the voltage conductor oscillator (l), which has a medium frequency ( (fc) has a service output, while outputs at the same distance (fc ± nfj) are outputs of band filters (5 / 1.5 / 2, ... 5/6) which are for band filters (5 / 1.5 / 2, ... 5/6) are connected by modulators (4a, 4b) to the frequency divider (2) for the output frequencies (2n.f <i) of the differential frequency (fj), where n = 1,2, ... n. -1-

Description

BACKGROUND OF THE INVENTION The present invention relates to a switching arrangement for generating equally spaced frequencies for carrier frequency multiplex equipment for multiple utilization of transmission paths.

As is known, carriers of different levels require carrier frequencies that are equally spaced and controlled by a high precision reference frequency.

One of the long-known solutions to this problem is the use of a so-called harmonic oscillator, which produces a series of pulses that are rich in harmonics from the control frequency and then selects the required carrier frequencies from the signal using band filters. The disadvantage of this solution is that the selection of harmonics requires the use of complex and costly bandpass filters.

For example, the following literature is used to produce frequencies of equal distance using harmonic oscillators:

Manual for Snapshot Mechanical and Electrical Engineers # 11 on page 207 on page 16.4. Fig. 4A shows a centralized carrier and pilot frequency generating frame, which is an ETG equipment of RFT, VEB Radio Funktechnik. Further, the same volume on page 211, page 16.09. Figure 12 illustrates a system for generating group carriers from 12 kHz.

Another known solution is the use of a so-called phase-closed loop (PLL), where a voltage-controlled oscillator (VCO) is synchronized with a control signal. By switching different frequency dividers in the loop, the necessary carrier frequencies can be generated.

The disadvantage of this method is that each carrier frequency requires the use of a phase-closed loop. Such a phase-closed loop solution is described by Siemens, S 42023 - C507-A1 / A2, and Primary Group Enumetzer-Gestell Bauweise 7R, which also produces group carriers distributed at 12 kHz.

A similar solution is known from ITALTEL (Societa Italiana Telecomunicazioni) from MTN 2 FDM Multiplex.

It is an object of our invention to provide a circuit arrangement without the drawbacks of the prior art.

The switching arrangement according to the invention is based on the recognition that a single phase-closed loop can produce a center frequency between the maximum and minimum frequencies of the required carrier frequencies, which is obtained when it contains an odd number of frequencies between the maximum and minimum frequencies. the number of frequency divisions between the maximum and minimum frequencies, so that in the absence of a center frequency, one of the center carrier frequencies can be generated by coupling one or two divider circuits to the voltage-controlled oscillator. One of the distribution chains is a binary frequency divider whose output produces a signal with the same frequency as the control frequency. This signal is applied to one input of a phase comparator and a control signal is applied to the other input of the phase comparator. The phase comparator output controls the frequency oscillator. In the event that the middle carrier frequency appears at one of the binary divisor stages, there is no need to apply a second divider chain, since the required carrier frequencies are all harmonic with the control frequency, so the binary divisor stages display the difference frequency, twice, Modulating the center carrier frequency with these frequencies in the modulator and selecting the two sidebands with band filters produces the middle frequency with two adjacent ones and two second, fourth, and so on. adjacent frequencies. Since the binary divider circuit produces symmetric rectangular signals that contain third and fifth harmonics at a sufficiently high level, the output of the modulator can also select two third and fifth adjacent frequencies. Thus, when the center frequency cannot be displayed, i.e. the number of maximum and minimum frequency divisions is even, the output signal of one of the binary divisors must be mixed with the output signal of an additional divider which derives the desired center frequency from the frequency controlled oscillator signal.

The switching arrangement of the present invention for producing equally spaced frequencies is particularly advantageous for carrier frequency multiplexers because the generation of the desired spaced frequencies with only one phase-closed loop instead of the previously used harmonic generators and multiple phase-closed loops and optionally, it is prepared using two dividing chains. In this way, the switching arrangement can be significantly simplified, the number of switching elements used can be significantly reduced and, as a consequence, the simple switching arrangement reduces the number of sources of error.

The present invention relates to a circuit arrangement for producing frequencies of equal distance, the frequency-controlled oscillator of which is stabilized by a discriminator and is connected to at least one frequency divider; the frequency divider, via modulator / modulators, is connected to the bandpass filters of the frequency to be produced. The novelty of the switching arrangement according to the invention is that if the frequency divider has a medium frequency output between the maximum and minimum frequencies to be produced, this output is the medium frequency output, while the outputs generating frequencies at the same distance are formed by outputs of band filters which is connected to the outputs of the frequency divider to determine the frequency spacing of the frequency divider through input modulators. If the frequency splitter does not have a medium frequency output between the maximum and minimum frequencies you want to produce,

-2195 An additional frequency splitter is connected to the 37 € oscillator with a medium frequency output.

The switching arrangement according to the invention may be formed by introducing an additional frequency divider between the voltage-controlled oscillator and the frequency divider to provide a basic frequency range for the oscillator.

Exemplary embodiments of the circuit arrangement of the present invention will be described in greater detail on the basis of the drawing, wherein:

Fig. 1 illustrates a circuit arrangement according to the invention with a single splitter circuit having an output providing a medium frequency between frequencies which are at the same distance between the maximum and minimum frequencies to be generated (case of odd numbering);

FIG. 2 illustrates an embodiment of a circuit arrangement according to the invention, wherein the frequency divider has an even number of frequency outputs and wherein an additional frequency divider is connected to the voltage controlled oscillator;

Fig. 3 shows an example of a generating circuit of the standard group transmitting apparatus according to the invention, together with the allocation of the required carrier frequencies.

Control input of the circuit arrangement of Figure 1 is controlled by one voltage oscillator output 3 phase comparator is connected, while the output of the feszültségvezéreit oscillator 1 is supplied to two voltage divider circuit, the outlet of the two voltage divider is connected to one input of the three phase comparator, the other input of the three phase comparator f _v is the control signal on. The voltage divider 2 has an output providing a center frequency f _c , as well as a difference frequency fj, twice, quadruple, etc., i.e. 2n.f (which produces frequencies j where n = 1.2 ... n. The middle frequency f _c A service output, coupled to the output outputs 2n.f (j), is directed to a modulator 4a, 4b whose output is connected to a bandpass filter 5/1, 5/2, ... 5/6. .5 / 6 outputs of bandpass filters for frequencies f _c ± NFD service outlets are in the same center frequency f _c distance, where n - 1,2, 3 ... n.

Figure 2 shows an embodiment in which the middle frequency f _c cannot be derived by binary division by a frequency divider 2, i.e. the frequency divider 2 has no output providing a middle f _c frequency, in this case between the frequency controlled oscillator 1 and the modulators 4. an additional frequency divider 6 is derived from the signal of the frequency-controlled oscillator 1 to derive the desired center frequency f _c .

The embodiments shown in Figures 1 and 2 function as follows:

As was a single phase-locked loop shown in Figure I or of the required carrier frequency in the middle between the maximum and minimum - in case of even number of frequencies, i.e. the middle frequency in the absence of rain the one centered f _c frequency such that the voltage is one-controlled oscillator of one or switching two distribution chains. One distribution chain is the binary frequency divider 2, which terminates in a signal of the same frequency as the control frequency. This signal is applied to one of the inputs of the phase comparator 3. The other input of the phase comparator 3 receives the control signal f _v . The output of the phase comparator 3 controls the voltage-controlled oscillator 1. In the event that the center frequency f _c appears in one of the stages of the binary frequency divider 1, there is no need to apply a second divider, since the required carrier frequencies are all harmonic with the control frequency; double, quadruple, etc., ie 2n.f (j frequencies where η = 1,2, ... n. Modulate the middle frequency f _c with these frequencies in the modulator 4 and the two side bands in 5/1, 5 / Selected with 2, 5/6 band filters, we obtain two adjacent frequencies of the middle frequency f _c and two adjacent frequencies of the second, fourth, etc. (See Fig. 1) Because the binary divider chain produces symmetric rectangular signals that are sufficiently high containing third and fifth harmonics, the output of modulator 4a, 4b is also subtracted from the two third, fifth adjacent frequencies It can be selected.

If higher harmonics were used, complex filters would have to be applied and the arrangement would no longer be advantageous over conventional solutions.

In cases where the center frequency f _c cannot be displayed at the appropriate frequency output of the frequency divider 2, an additional divider 6 is assigned to each stage of the binary frequency divider 2, which produces the desired middle frequency f _c from the signal of the frequency oscillator. Figure 2). Because all the required carrier frequencies are some harmonic of the control signal, always

In 4Q, one can find an oscillator frequency and a second divider that can produce the desired average frequency f _c . The binary frequency divider 2 does not need to be connected directly to the oscillator, as binary divider 2 and

A third frequency divider 7 is connected between the voltage-guided oscillator 1 and whose pitch ratio can be selected so as to provide an oscillator in the preferred frequency range.

Fig. 3 shows an example of a carrier power connection of a standard group transfer apparatus with a circuit arrangement according to the invention, with the required frequency assignment. The carrier frequencies, as shown in the figure, are 420, 408, 516, 564 and 612 kHz. The control frequency is 12 kHz.

Claims (2)

A switching arrangement for generating frequencies which are equidistant from one another and having a frequency drive oscillator stabilized by a frequency discriminator 3195 376 connected to at least one frequency divider; the frequency divider, via modulators / modulators, coupled to the bandpass filters of the frequencies to be generated, characterized in that the frequency divider (2) has an output producing an exactly average frequency (f _c ) between the desired maximum and minimum frequencies, forming the medium frequency (f _c) ), or an additional frequency divider (6) is connected to the voltage guide It oscillator (1) having an output producing a medium frequency (f _c ), while outputs providing equal frequencies (f _c ± nfj) are bandpass filters (5 / 1.5 / 2, ... 5/6), which inputs of the band filters (5/1, 5/2, ... 5/6) are connected to the frequency divider (2) by modulators (4a, 4b) (f <j) for the outputs of the determining frequencies (2n.f (j), where n = 1.2 ... n. Circuit arrangement according to claim 1, characterized in that an additional frequency divider (7) is provided between the voltage-controlled oscillator (1) and the frequency divider (2), which provides a preferred frequency range for selecting the base frequency of the oscillator torque.