DK144170B - PROCEDURE FOR PHASING THE REFERENCE BELLS TO A DATA TRANSFER OF FREQUENCY DIFFERENTIAL PHASE MODULATION - Google Patents

Description

(¾ ^

(19) DENMARK \ SV

| F | (12) PUBLICATION <N> 1 170 B

DIRECTORATE OF THE PATENT AND TRADEMARKET SYSTEM

(21) Application No. 5987/74 (51) IntCI. * H OA L 27/18 (22) Filing Date 18 Nov. 1974 (24) Race day 18 Nov. 1974 (41) Aim. available May 20, 1975 (44) Presented Dec. 28; 1981 (86) International Application No. "(86) International Filing Day (85) Continuation Day - (62) Master Application No. -

(30) Priority 19 · Nov. 1975, 2557705, DE

(71) Applicant SIEMENS AKTIENGESEELSCHAFT, Berlin and Munich, 0-8000 Munich 2, DE.

(72) Inventor Erich Burger, DE.

(74) International Patent Bureau.

(54) Method for phase-in of reference carriers into a data transmission system with frequency differential phase modulation.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a method for phasing reference carriers in a data transmission system with frequency differential phase modulation, in which several carriers having mutually fixed phase position on the transmit side are transmitted together and phase modulated in sequential modulation sections, where one of the base carriers is used as the base carrier for the base wave. sequence differential phase modulation and where the transmitted data on the receiving side is recovered from the transmitted phase modulated carriers by demodulation with the reference carrier generated on the receiving side and the reference waves and reference-3. the carrier waves on the transmitting and receiving sides, respectively, are associated with their basic oscillation with the same fundamental frequency, the carrier frequencies and reference waveforms respectively being multiplied by the fundamental frequency and where on j. the sending page to an over period consisting of a first number of basic periods is associated with a second number of modulation sections.

2 144170

In the above-mentioned methods for frequency differential phase modulation, the same parts of the modulation sections are associated with the basic periods appearing on the transmit side and on the receiving side. The invention aims to provide a method which enables this association with a slight technical tender.

The method according to the invention is characterized in that a reference signal is generated on the transmit side which characterizes the beginning of the modulation sections as well as characterizes the beginning of the over period, that the base carrier is modulated with the reference signal, so that the modulated base carrier contains information about the beginning of the modulation sections and and that the phase location of the reference carriers on the receiving side is set by the modulated base carrier.

The method according to the invention is characterized in that it is achievable with a small technical range, because the information regarding the beginning of the modulation sections and the upper period is not transmitted with an additional carrier, but with the base carrier, which is nevertheless available for transmitting the base phase for the frequency differential phase modulation.

It is useful as a reference signal to produce a square-shaped signal whose pulse flanks coincide with the beginning of receiving side modulation sections and whose square pulses have two pulse widths, a first pulse width characterizing the duration of the modulation sections and a second pulse width characterizing the over periods.

Conveniently, according to the invention, the first pulse widths of the reference signal have a duration of every two modulation sections and the second pulse widths of a duration of every three modulation sections.

Embodiment examples according to the invention are explained in more detail below with reference to the drawing, wherein like objects are provided with similar reference numerals and in which fig. 1 shows a system for transmitting data with frequency differential phase modulation, FIGS. 2 and 3 signal appearing in the FIG. 1; FIG. 4 is a more detailed representation of the embodiment of FIG. 1 diagrammatically illustrates synchronization device; FIG. 5 are time diagrams of signals appearing in the operation of the FIG.

4, and FIG. 6 is a more detailed representation of the embodiment of FIG. 4 schematically plotted rating link.

FIG. Figure 1 shows a data transfer system for transferring data by means of frequency differential phase modulation. The data source DQ outputs the data in the form of a binary signal which assumes two different amplitude values whose binary values are continued on page 2, penultimate line.

3 14-4170 direction KD. Modulators MD1, MD2, MD3, MD4 are connected to the coding device KD, which are separately supplied by a generator GEN to a carrier respectively F1, F2, F3, F4. For the purpose of simplifying the drawing, only four modulators MD1-MD4 are shown, whereas in practice a substantially larger number of modulators and corresponding carriers are generally used.

The phase modulated carriers F10, F20, F30, F40 are output from the outputs of the modulators MD1, MD2, MD3, MD4 and are jointly applied to the transmitter SE, transmitting over a transmission line, e.g. over a shortwave stretch, to a receiver EM.

In the receiver EM, the transmitted signal mixture is amplified and over the output the amplified signal mixture G is applied to the inputs of demodulators DM1, DM2, DM3, DM4 and to a synchronization device SYN. The sync device SYN provides reference carriers R1, R2, R3, R4, by means of which the individual phase modulated signals are demodulated. With the outputs of the demodulators, decoding devices DK1, DK2, DK3 are connected, which rescues the coding performed using the coding device KD. With a parallel / serial converter PS, the parallel input data is transmitted in series to a data receiver DS. For example, as a data receiver, there may be a remote printer or a computer screen.

FIG. 2 schematically shows the carriers F1-F4 multiplied by the fundamental frequency of the fundamental oscillation Fs. The fundamental oscillation Fs and the carriers F1-F4 have a fixed phase position. The zero crossings of the fundamental fluctuation Fs are at the times of, t20, t30 ... tl43, tl52, t161. At these points, all zero passes of the carriers F1-F4 coincide simultaneously. In one embodiment, the fundamental oscillation Fs has a pulse tracking frequency of 80 Hz. Thus, in this embodiment example, the period duration p of the fundamental oscillation Fs is 1/80 sec.

During the phase modulation, phase changes occur in the period of successive modulation sections m. The modulation section ml, which lasts from time to time t21, is somewhat larger than the base period pi that lasts from time to time t20. In this embodiment, the modulation sections ml, m2 ... ml4, ml5 follow with a sequential frequency of 75 Hz, so that each modulation section m has a duration of 1/75 sec. The beginning and ending of the modulation sections m generally do not coincide with the zero crossings of the fundamental oscillation Fs. However, at the times to and tl61, the beginning of the modulation sections m coincides with the zero crossings of the fundamental oscillation Fs. Thus, the upper period q, beginning at the time of and ending to the time tl61, comprises 16 basic periods pi, p2 ... pl5, pl6 and 15 modulation sections ml, m2, ... ml4, ml5. For the sake of clarity, the drawing shows only the first two and the last two basic periods and modulation sections. The follow-up frequency for the period is 5 Hz.

To the carrier side waves F1-F4 appearing on the receiving side, reference waves R1-R4, whose tracking frequencies are multiplied by the receiving side's fundamental oscillation Fe, correspond. The reference carrier R1-R4 appearing on the receiving side and the receiving side fundamental oscillation Fe are also connected to each other by a fixed phase0 With the zero oscillations on the receiving side Fe1's zero passages, all zero passes of the reference carrier R1-R4 coincide.

In the modulation system with frequency differential phase modulation, the data to be transmitted are connected to phase differences between two neighboring carriers in each case. For example, such data can be transmitted by phase differences for the carriers F2 and F3. Since the carriers F1-F4 have different period durations, these phase differences are continuously changed from modulation sections to modulation sections. Admittedly, the phase differences have the same value after consecutive base periods p, but not consecutive modulation sections m. For example, the carriers F1 and F2 at the time have a phase difference of 0 °, whereas after the modulation section ml to the time t21 have a phase difference of 90 °. If on the sending side to the base periods p1 pl6, parts of the modulation sections ml-m1 5 are associated, the phase locations of the reference carriers R1-R4 on the receiving side must be determined so that the same parts of the modulation sections ml-ml5 are linked to the receiving side base periods .

For phasing in the reference carriers R1-R4, according to FIG. 1 in the generator GEN a reference signal E, which contains information on when the upper period q begins on the transmit side. With the reference signal E, in the modulator MD4, the carrier F4 is modulated and the modulated carrier F40 is output to the transmitter SE and transmitted as the base carrier to the receiver EM. On the receiving side, the phase location of the reference carriers R1-R4 is set by the modulated carrier F40.

The FIG. 3, in comparison with FIG. 2 shown in a different time scale. From time to time t311, a full period of the reference signal E is shown, which is equal to the sum of the two over periods q and q2. Thus, the time from time to time t311 in the present embodiment Example 30 comprises modulation sections. The reference signal E consists of square shaped pulses, of which pulses E3, E4, E5, E6, E7, E8 each have a duration of two modulation sections, whereas pulses E2 and E9 each have a duration corresponding to three modulation sections.

5 mi7p

FIG. 4 shows a more detailed example of the embodiment of FIG. 1 sync device SYN. This synchronization device consists of an oscillator OS, of a frequency change step FS, of frequency dividers FT1, FT2, of a rating switch BW, modulators MD5, MD6, and of correlators KR1, KR2, KR3, KR4, of phase shift link PS1, PS2, of a signal converter SU, a rough synchronization step GSYN and of an analog / digital converter AD.

With the oscillator OS, a clock signal with relatively high pulse sequence frequency is generated, which signal is applied to the frequency change step FS, which either causes a dimming or a single pulse dimming.

The frequency divider FT1 outputs that in FIG. 3 and the reference carriers RI, R2, R3, R4. The frequency divider FT2 produces the ones in FIG. 3, A1, A2, A3, A4.

With the signal A1, using the modulator MD5, an amplitude modulation is effected, where during the duration of the 1 values of the signal A1 a phase of 0 ° of the reference carrier R4 is set, whereas during the duration '. the value of the O values of the signal A1 does not output any signal. With the modulator MD6, a phase modulation is effected in such a way that the reference carrier R4 is emitted with the phase 0 ° during the duration of the 1 values of the signal A2, while the reference carrier R4 is emitted with a phase of 180 ° for the duration of the O values. Further, each of these modulated signals is affected by the integral rate signal A3, thereby producing a signal K and H, respectively, as shown in FIG. 4th

In FIG. 5 is a diagram above F41 showing the phase location of the embodiment shown in FIG. 1, signal F40. Thus, the two binary values in the diagram F41 correspond to phases of 0 ° and 180 °, respectively, of the signal F4Q. The diagram K shows the amplitude of the reference carrier R4 to be modulated, whereas the reference numerals 1 and 0 respectively are associated with a certain amplitude with the phase 0 ° and no signal. The diagram H shows the phase location of the reference carrier R4 to be modulated, whereby the reference numerals 1, 0 and -1 are associated respectively with a phase of 0 °, no signal and a signal with a phase of 180 °.

To produce the signals L, Μ, N, P, there are two different species of correlators. The correlators KR1 and KR2 form the correlation functions between the signal corresponding to the diagram F41 and the signal corresponding to the diagram H. The correlators KR3 and KR4 form the correlation functions between the signal corresponding to the diagram F41 and the signal corresponding to the diagram K,

The signal corresponding to the diagram F41 is contained in the signal mixture G. In order that the correlators also supply a usable signal at any phase position of the signal corresponding to the diagram F41, there are two phase shift links PS1 and PS2, each of which cause a phase shift of 90 °.

144170 6

It is evident from signals N and L that each correlator KR1, KR2, KR3, KR4 always integrates over two time periods ten and thus over two modulation sections m. The signals L, Μ, N, P are a measure of the temporal shift between the signal corresponding to diagram F41 and the signals corresponding to diagrams K and H.

FIG. 5 shows three cases which refer to properly synchronized reference carriers, to pre-running reference carriers and to the dead-time range. The signals N, L, P, M can assume DC voltages between + 2V and -2V. In particular, the values are OV, -IV, -2V. In the first case, the diagram part K1 falls exactly within a modulation section m temporarily. This case is characterized by the signal N, which assumes a voltage at OV in the point NI. The dead time signal Q assumes the binary value 0.1 the second. In this case, the signals N and L have the same polarity at the points N2 and L2, respectively. At a backward signal part K2, these two points N2 and L2 would have opposite polarity. The dead-time signal Q assumes the binary value. 0.1 the third case, the receiver's time base is offset by a modulation section m relative to the signal part K3.This case is characterized in that the signal L at the point L3 assumes a voltage of OV. In this case, the dead time signal Q has the binary value 1. The dead time signal is thus a signal. used to signal whether there is some correspondence between the carrier side and the receiver side carrier.

The signals N, L, P, M serve as a criterion for the rough phase correspondence between the modulation sections occurring on the transmit side and on the receive side. This phase matching is referred to by the present transfer method as coarse synchronization. This coarse synchronization is performed in a manner known per se with that of FIG. 4 shows the synchronization step GSYN. The coarse synchronization step GSYN, on the one hand, is associated with the frequency change step FS and causes a dimming or dimming of individual pulses. On the other hand, the coarse synchronization step emits a signal S, which always assumes the binary value 1 when coarse synchronization is completed.

In addition, the signals N, L, P, M also serve to phase in the upper period, so that the same parts of the modulation sections are linked both on the sending side and on the receiving side to the basic periods. This phase-in is carried out with that of FIG. 4 shows a rating circuit BW schematically shown to the signals A4, Q, S. The signal W assumes a 1 value only if the level of the signal in FIG.

1 signal mixture G entered is in the desired range.

The FIG. 4, the analog / digital converter receives the analog signals N, L, P, M and outputs over its outputs the binary signals N4, L4, P4 and M4.

Then, to analog values below a predetermined threshold value, the binary value 0 is assigned and to analog signals above the predetermined threshold binary value 1. For example, the signal N until the point N3 is reached, the binary value O is assigned by the signal N4 and after the point N3. of signal N, signal N4 assumes the binary value 1. As can be seen in FIG. 5, a polarity reversal is thereby also made.

The FIG. 4, the signal converter stage SU receives on the input side the signals N4, L4, P4, M4 and produces the dead time signal Q. The operation of this signal converter stage SU is shown in the following table.

N4_L4_P4_M4_Q_ 1 0 0 0 1 0 10 0 0 0 0 10 1

Thus, with the signal Q = 1, the dead time range is signaled. Thus, a dead time range occurs if either N4 = 1, L4 = 0, P4 = 0, M4 = 0 or N4 = 0, L4 = 0, P4 = 1, M4 = 0. The signal Q = 0 indicates that no dead time zone is present.

FIG. 6 shows a more detailed assessment link BW. It consists of NAND ports ΝΑΙ, NA2, NA3, of an inverter IN, of NOR ports N01, N02 and of bistable tipping stages STI, ST2, ST3.

From the output of the gate NA1, an O signal is output only if a dead time range is signaled with Q = 1, if a completed coarse synchronization is signaled with S = 1 and if a desired level of signal mixture is signaled with 1 ^ = 1. STI and ST2 constitute a first counter and the step ST3 constitutes a second counter. As soon as the first counter of steps ST1 and ST2 has counted to three, the signal D appears on the output, which results in the fact that in the FIG. 4, a frequency change step FS is performed, a pulse blinding is performed. Thus, a phase shift is performed on a modulation section. Simultaneously with the output of signal D, the first counter is blocked over the inverter IN and over the gate N01, so that with the signal S = 1 in each case only a single phase offset with a modulation section is performed. The step ST3 is fed to the one shown in FIG. 3, which has a pulse sequence frequency of 2.5 Hz.

Above the output of the gate NA3, the two steps ST1 and ST2 are reset if no signal S = 1 occurs within a period of 2.5 Hz, whereby the completed phase-in is signaled.

Thus, in the phase-in of the reference carriers produced on the receiving side R1, R2, R3, R4, a rough synchronization is first performed in a manner known per se. In this coarse synchronization, the sending side modulation section and the receiving side modulation section are covered. In this way, it is usually not immediately achieved that the first basic period and the first modulation

Claims (2)

144170 8 sections begin simultaneously. In this case, the dead time signal Q = 1 is generated because, with reference to FIG. 5 dead time areas described appear. Using signal D, the receiver's time base is phase shifted by a modulation section. This process is continued until, with Q = 0, no longer dead zones are signaled. Thus, both coarse synchronization and phase-in of the reference carriers RI, R2, R3, R4 are completed. The FIG. 4, for example, the signal converter stage SU can be formed by an equivalent port GT1, by the AND gates GT3 and by the NOR gate GT2. A method of phase-in of reference carriers in a data transmission system with frequency differential phase modulation, wherein several carriers of mutually fixed phase position on the transmit side are transmitted together and phase modulated in successive modulation sections where one of the carriers responds. is turned as a base carrier for transmitting the base phase of the frequency differential phase modulation and where the transmitted data on the receive side is recovered from the transmitted phase modulated carriers by demodulation with the reference waves generated on the receive side, the base waves are transmitted to the carrier and the reference carrier with the same fundamental frequency, the carrier frequencies and the reference carrier frequencies respectively being multiplied by the fundamental frequency, and where on the sending side a second number of modulation periods is associated with a second number of modulation sections, characterized in that a reference signal (E) is generated on the transmission side. which characterizes the beginning of the modulation sections and partly the beginning of the period (q) that the base carrier (F4) is modulated with the reference signal (E) so that the modulated base carrier (F40) contains information about the modules the beginning of the sections and an information regarding the beginning of the period (q) and that the phase location of the reference carriers (R1-R4) on the receiving side is set by means of the modulated base carrier (F40). Method according to claim 1, characterized in that, as a reference signal (E), a square-shaped signal is produced whose pulse flanks coincide with the beginning of the receiving side modulation section and whose square pulses have two pulse widths, a first pulse width characterizing the duration of the modulation sections. , and another pulse width characterizes the beginning of the upper period (q).