Try the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents. Method and apparatus for the coherent demodulation of a digitally modulated carrier EP A1. To perform coherent demodulation of the carrier emitted by useful bursts regularly spaced in time, following with phase continuity from one phase to the, a device is used which comprises elevating means 18 to the square of the carrier frequency f i modulated to display the frequency 2f 1a filter 20 narrow frequency band isolation and a frequency divider by two Options method of coherent demodulation carrier to digital modulation by phase shift r25 frequency shift continuous phase carrier transmitted by useful bursts regularly spaced in time with phase continuity from one binaires to the next, which method is recovers the carrier frequency by squaring the carrier and selecting the carrier frequency within the obtained spectrum characterized in that acquisition bursts options at the frequency of the carrier, having constant and particular characteristics, having a duration greater than that of the useful bursts, with a repetition period longer T T of at least one order of magnitude as the transmission period of the modulated carrier burst, and by subjecting the bursts acquisition to squaring and insulation selection of frequency 2f 1 twice the carrier frequency using said characteristics of salves d'acquisition. The method of claim 1, characterized in that it is the acquisition burst by a insulation of bits at 0 and in that identifies the line at the frequency 2f 1 twice the carrier frequency as the one having a maximum amplitude greater than a determined threshold. A method according to claim 3, characterized in that alters the oscillator frequency in steps substantially equal to the filtering bandwidth. A method according to any preceding claim, for the carrier recovery in the broadcasting-satellite broadcast signal consisting of time-division multiplexing of a frequency modulated analogue carrier by the image signal during the active duration of a TV line and a digital carrier sent during the blanking interval, characterized in that each acquisition burst transmits during a line blanking interval. Claim 6, characterized in that the means: Device according to claim 7, characterized in that the logic 37 comprises a comparator 44 for comparing the amplitude U 1 with r25 predetermined threshold U 0the control sortiee closing a circuit 40, 43, 41, 42 of progressive increase of the control voltage of the oscillator 31 as long as the threshold is not reached. Device according to claim 8, characterized in that the output of the comparator also controls a switch 48 for adding, to the voltage control oscillator, a correction voltage delivered by a r25 discriminator 28 from the signal having passed through the narrow band filter 20 and options amplitude limiter Device for coherent demodulation usable to implement the method according to claim 1, comprising means 18 squaring the carrier frequency f1 modulated to display the frequency 2f 1and a frequency isolating filter 64characterized in that it comprises means for mixing, before application to binaires filter 64the frequency 2f 1 twice the carrier frequency at a frequency twice the frequency supplied by a local oscillator 31 controlled voltage to create an error signal, a control logic capable of elaborating the voltage control oscillator signaux from the filter output signal insulation and output signal of a phase locked loop 65 which receives the dual frequency signal of the carrier frequency and the double frequency signal from the output of the local oscillator. The invention relates to coherent demodulation of digitally modulated carrier by phase shift or frequency shift continuous phase, carrier transmitted in bursts regularly spaced in time, with continuity of the phase of a burst to the signaux. Digital modulation phase shift may be any of the types r25 used: Signaux invention binaires particularly suitable for use in the satellite broadcast domain using a di. On this multiplex timing diagram shown in Figure 1. This system allows to broadcast eight digital channels of high-quality sound associated with the television picture. In the case where the synchronization is transmitted during the frame, the entire duration of the burst can be devoted to transmitting useful data. It is not necessary to issue a preamble at the beginning of each burst as is conventionally done in the multiple access by time division TDMA. There are already known various demodulation processes applicable to satellite broadcasting system in C, including using PSK modulation currently proposed. Of these methods, differential demodulation is being put forward, because simpler to implement than the coherent demodulation. In particular, in satellite broadcasting, the differential demodulation does not ensure a simultaneous broadcast of the signaux and sound as soon as the carrier to noise ratio is less than a higher value than in the case of coherent demodulation. It has been found experimentally that the interruption of service to the sound was held for a carrier-to noise equal to 7. The invention aims to provide a coherent demodulation method, that is to say, of the following type which is recovered carrier frequency by squaring the carrier and selecting the carrier frequency in the spectrum obtained, which retains insulation to greater noise r25 the differential demodulation processes and at the same time, has an increased operating safety as regards notamment. Before describing the invention, it may be useful to recall the operating principle of coherent demodulators. Assuming the modulated carrier 10 emitted during the period T N of bursts with a repetition period T L, the carrier can be written: In the case of r25 2-PSK demodulation two phase states, s t is expressed as: In the case of a type of PSK or MSKs t can be written in the general form: This demodulation can be performed by a circuit of the kind shown in Figure 3 comprising, from the inlet of the modulated carrier, a bandpass filter 12 whose output is applied on the one hand, to a binaires 14, signaux secondly to a carrier recovery circuit The circuit 16 typically uses the carrier recovery mode of a modulated biphase signal by squaring of this carrier, for example using an analog multiplier 18, the extraction of the comnosante frequency output signal r25 to a value of f 2 f 1 function with a filter 20 and finally division by two with a divider Options sees in effect that the resulting output signal of the multiplier 18 contains a component around the frequency insulation f 1, which is expressed as: The broadcast signal bursts u t can be decomposed into Fourier series and be written: But we see that in the usual case where N T binaires less than T L, there are several insulation that have a very similar options. Such options bandwidth may be achieved with a crystal filter. The invention allows to remove this disadvantage. In the process according to the invention, the acquisition bursts are transmitted to the carrier frequency, having constant and particular characteristics, having a greater than the useful burst duration, with a longer repetition period of at least an order of magnitude that the transmission period of the modulated carrier burst, and binaires subjecting the bursts elevation squared acquisition and selection of the frequency twice the carrier frequency using binaires characteristics of bursts 'acquisition. The amplitude of the output signal of the filter 20 to narrow options Figure 3 increases with the duration of the burst acquisition, and therefore that the ratio between the amplitude of the useful line and the amplitude of a line parasite. The use of a duration T S acquisition burst greater than the duration T of a useful N burst frequency f provides a much higher ratio of the amplitude of the useful line and the amplitude a parasitic line, since the amplitude of the output signal of the filter 20 to narrow band increases with the duration of the burst. This method thus uses a different approach from that disclosed in US-A-3, and uses different means. It uses a long acquisition burst transmitted at high intervals to select with certainty the carrier frequency, thus removing the risk of error on the carrier frequency recovered from the useful bursts, bursts between successive acquisition. The transmission of the acquisition burst is controlled by a signal v t periodic, t period T, having the shape shown in Figure 4 and having the expression: In applying the method to the satellite broadcasting, the signal v t of acquisition is transmitted during a line blanking interval and the durations of the different transmitted signals can then be r25 follows: The burst must correspond to the frequency f 1 emission and can therefore be constituted by a insulation of binary elements at zero. The signal around the frequency 2f 1 obtained after squaring the modulated carrier by a circuit such as 18 options expressed as: This last formula shows binaires the frequency component 2f 1, and it alone, is amplitude modulated by the signal v t. This modulation allows to identify f 1 and to remove the ambiguity in the carrier recovery from subsequent bursts helpful. Before explaining various embodiments that allows its use for modulation disambiguate f 1, it should be noted the action of the signal y 1 of a rectangular filter center frequency f c, signaux W such as 1 r25 W "1 crystal filter for example. La fonction de transfert H v de ce filtre a pour expression: The transfer function H v of this filter is expressed as: It is then easy even in the presence of noise, identify this line by an amplitude detection followed by a comparison with a threshold and an acquisition of the identified line. In this case, the line frequency 2f 1 is easily identifiable as one having a maximum amplitude greater than a determined threshold. In a particular embodiment of the invention, mixing the useful bursts options acquisition, after squaring, and the output signal of a variable frequency voltage controlled oscillator also being squared, and what gradually changing the control voltage of the oscillator until the signal amplitude obtained by mixing and subjected to narrow band filtering exceeds a predetermined threshold. The oscillator frequency change can be done in steps substantially equal to the filtering bandwidth. The invention will be better understood from reading the following description of specific embodiments thereof, given as non-limiting examples. The description refers to the accompanying drawings, wherein: The carrier recovery circuit whose block diagram is shown in Figure 5 is of the type comprising a narrow band filter, which is generally constituted by binaires quartz filter. This circuit, like that of Figure 3, comprises an input band-pass filter 12, followed by a circuit 18 for squaring the modulated carrier signal it receives, so as to show the frequency 2f, in its output signal y 1. Between the squaring circuit 18 and the crystal filter 20 and center frequency f c is interposed a first multiplier The multiplier 24 also receives a frequency signal 2f 1 -f c provided by a second circuit 23 of squaring, constituting the last element of a acquisition loop which will r25 described later. The oscillator 31 directly attacks the second multiplier 30 and, through the circuit 23 squaring, the first multiplier The role of the control logic is to provide a voltage allowing, in the acquisition phase, to vary the oscillator signaux within a range corresponding to the maximum frequency variation of the modulated carrier: Figure 6, where components corresponding to those of Figure 5 are designated by the same reference numbers, shows r25 possible structure of insulation of these components The circuit 18 for squaring the modulated signal and the circuit 23 elevation the square of insulation signal from the oscillator 31 may be constituted by type of frequency doublers RK3 followed by OM type amplifier for compensating insertion losses of the doubler. In Figure 6, this filter 20 is preceded by a transistor amplifier 38 and impedance matching. The limiter 25 can be a type of circuit NE marketed by the RTC Company. The divider 2 2 can be constituted by a D type flip-flop followed by an impedance adapter. It may especially be a rocker SN 74 LS 74 followed by an impedance matching SN 74, The frequency discriminator 28 signaux be constituted by a type of ring modulator SBL 1 as the product of the upstream signal of the narrowband filter 20 and the output signal of the limiter The upstream signal of the limiter 20 is taken before options Before being applied to the frequency discriminator 28, it signaux through a variable phase shifter with two transistors 39, thereby adjusting the phase for an output voltage of 0 at the center frequency f of the filter to quartz. The control logic 37 may have any constitution enabling it to fulfill the role defined above. It may in particular correspond to the diagram shown in Figure 7. An AND logic circuit 43 between the oscillator 40 and the counter 41 constitutes a door that will stop the scanning when the acquisition has occurred. The signal U obtained at the output of the amplitude detector 26 Figures 5 and 6 is applied to a comparator 44 which outputs a logic level V such that: The logic signal output of the comparator 44 consists of a sequence of pulses of period T and T adjacent duration T s. The time constant T of the monostable is chosen equal to a few periods T T of the input signal. Le fonctionnement du circuit binaires le suivant: The circuit operation is as follows: The switch 48 is off that is to say corresponds to an open circuit. If the counter r25 its maximum capacity without an acquisition, it starts counting. In another embodiment, it simply returns to zero. The scanning is stopped, the switch 48 is on and the control voltage U 2 is kept applied to the controlled oscillator voltage. As an application example of the invention, will be described now with reference to Figure 8, the overall constitution of a satellite broadcasting receiver system C incorporating a kind of recovery circuit shown in Figures 5 and 6. The receiver includes an input mixer 50 for transposing the input signal received at the first intermediate frequency around 1 GHz transposed to a second lower frequency about MHz for exampleby multiplying by the signal insulation local oscillator that is tuned so as to select the desired channel. The mixer 50 la. The constant-amplitude signal obtained at the output of the amplifier 53 is divided into two paths. One of the paths is subject to processing of the image signal and the frame synchronization. Signaux well-known type, this treatment will not be described in detail and just remember that the processing path performs the following functions: The other path at the output of the amplifier 53 ensures binaires coherent demodulation of the insulation signal. It comprises a band-pass input filter 12, followed by a switch 58 shown as a mechanical element for simplicity. When the frame synchronization word has been recognized by the processing unit 57, the time base generates the switch control r25 58 which applies the signal to the digital demodulator only binaires the digital bursts. The signal from the filter is in turn divided into two lanes. In this case, the oscillator 31 of the carrier recovery circuit is fixed crystal oscillator and the error voltage U 4 at the output of control logic circuit 37 is applied to the local oscillator 51 transposition, added an adder 61 to the channel selection signal provided by a selection member 62 adjustable. The other filter outlet channel 12 includes a mixer which receives on its other input the recovered carrier, and outputs, after low pass filtering 64, the demodulated digital signal. We will now describe briefly the operation of the carrier recovery circuit, in the case where it is incorporated in a broadcast receiver of the kind shown in Figure 8. When the power-v-on of the receiver, the user must pre-select the frequency insulation the local oscillator 51 to the desired channel by means of the selection member The control logic circuit 37 will then intervene for varying the frequency of the oscillator 51, if necessary, on both sides of the preselected frequency. The acquisition is done in two steps. During the first step, there is recognition of the word synchronizing frame by the processing unit When this synchronization word is recognized, the time base unit 57 generates a signal which is applied to the switch 58 to turn it on. Digital bursts are then sent to the carrier recovery circuit. During the second step, there is identification of the carrier acquisition signal by the circuit 60, for identification of the rays which is modulated in amplitude. The frequency sweep continues until the carrier acquisition signal has been recognized. From this effective recognition, there is stopping the frequency sweep by blocking the switch 58 and commissioning of the automatic frequency control circuit. The receiver is then stabilized operation and provides the digital data to In the alternative embodiment of the invention shown in Figure 9, wherein the members corresponding to those of Figure 5 are designated by the same reference number, the carrier recovery is provided by a phase locked loop. In the variant of Figure 9, the voltage controlled oscillator 31 has a neighboring resting frequency of f 1. The oscillator output signal 31 is applied to a signaux circuit 23 to make appear a carrier frequency 2f 1 which is applied to one input of a phase comparator 63 which replaces the multiplier 24 of Figure 5. The output voltage e of the phase comparator 63, an amplitude proportional to the phase difference of the input signals is applied to a low-pass filter 64 whose output voltage U signaux is the error voltage applied to the control logic 37 to enable the phase locking of the binaires signal during the acquiring step. The phase comparator 67 is used as a synchronous amplitude detector. The signals u '1 and u 2 are applied to the control logic circuit 37 which provides the control voltage of the oscillator and may be the one of Figure 8. In all cases, the device options the removal of ambiguity by signaux the carrier frequency by mixing with the frequency supplied by a local oscillator, so that the central line of the resulting frequency corresponds to the passband of the filter thus isolated in surely the carrier frequency. During an acquisition phase, the frequency of the local oscillator is insulation gradually, generally in steps substantially options to the filter bandwidth, until the maximum amplitude at the outlet of the filter narrow band exceeds a predetermined threshold, selected to be placed between the value corresponding to the insulation, by the filter, the central line of the burst acquisition and that corresponding to the isolation by the filter, a line lateral. Once the acquisition is completed, the frequency of the local oscillator is retained and carrier recovery is performed on the useful bursts, as in a conventional device. CH DE GB IT LI NL SE. 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Presentation de Signal Option - Statistiques Options Binaires
Presentation de Signal Option - Statistiques Options Binaires
3 thoughts on “Options binaires signaux r25 insulation”
However, their counterparts claim that the difficulty and unknown side effects (coupled with a few unsuccessful and fatal trials) will cause damage greater than any potential good.
However, their counterparts claim that the difficulty and unknown side effects (coupled with a few unsuccessful and fatal trials) will cause damage greater than any potential good.
I draw my fingers softly through my sensibly cropped middle aged locks and sigh.
UCB Main PN1997.W593 R87 1992 UCB Moffitt PN1997.W593 R87 1992.