EP0744723B1 - Method and device for receiving signals from a plurality of transmitters - Google Patents

Description

The invention relates to a method and device for receiving signals from a plurality of transmitters, for example infrared, such as remote controls for audio-visual devices. The invention also relates to a remote control used in conjunction with the device mentioned, as well as a system including a receiving device and a plurality of transmitters. The invention applies in particular in the field of video and television.

Many consumer electronics devices can be controlled by a wireless remote control transmitting commands to a receiving device of the device to be controlled. This transmission is generally carried out by infrared, ultrasonic or radio frequency, the data being modulated on an appropriate carrier.

It may be desirable to be able to use multiple remote controls simultaneously with a single receiving device. This raises the problem of interference between these remote controls, as well as the problem of identification of a transmitting remote control by the receiving device.

The application for a certificate of utility FR 2 698 979 proposes a system using remote controls and a receiver.

The Elektor Electronics document, 17, Sept. 1991, No. 192, London, GB, pages 34-38, discloses a remote control system with at least two transmitters where for each transmitter the data transmitted is represented by the time interval between two pulses consecutives. The invention is defined by the claims.

pour chaque émetteur, les données ("0", "1") étant représentées par l'intervalle de temps (T0i, T1i) entre deux impulsions consécutives émises par cet émetteur,

lesdits intervalles de temps ainsi que la largeur des impulsions (Tpi) étant caractéristiques de chaque émetteur,

ledit procédé comprenant les étapes:

de réception d'un signal résultant de la superposition des signaux émis par lesdits émetteurs,

de détermination des paramètres des impulsions dudit signal résultant, lesdits paramètres comprenant la largeur des impulsions ainsi que leur espacement,

d'attribution d'une donnée à un émetteur en fonction de ces paramètres

The subject of the invention is a method of receiving signals from at least two transmitters (RCi) characterized in that,

for each transmitter, the data ("0", "1") being represented by the time interval (T0i, T1i) between two consecutive pulses emitted by this transmitter,

said time intervals as well as the width of the pulses (Tpi) being characteristic of each transmitter,

said method comprising the steps:

receiving a signal resulting from the superposition of the signals transmitted by said transmitters,

determining the parameters of the pulses of said resulting signal, said parameters comprising the width of the pulses as well as their spacing,

allocation of data to a transmitter based on these parameters

The use of transmitters emitting pulses of different width and encoding data by time intervals also characteristics of these transmitters allows by an analysis appropriate to separate the superimposed information with a large efficiency.

According to a particular embodiment, the data are the two possible values of a bit.

According to a particular embodiment, one associates with each sender data representing the state of a message from this transmitter.

According to a particular embodiment, the state of the message is waiting for the first bit of a message, waiting for bits waiting for the end of the message or waiting for the end of the rest time between two messages.

According to a particular embodiment, a first bit is detected for a given transmitter when the time interval between the current pulse and one pulse among the pulses previously received is equal to one of the intervals defining a value bit for said transmitter and that the duration of said pulse among the previously received pulses is equal to the duration of a pulse associated with said given transmitter.

According to a particular embodiment, the comparison between the time interval between said two pulses and the intervals setting a bit value for said transmitter is performed by increasing intervals defining information, all pulses previously received and stored being reviewed for each intervals defining a bit value.

According to a particular embodiment, the intervals defining a bit value being two in number, if no bit is detected but there was a tie between the shortest duration corresponding to a bit value and the time interval separating the current pulse and a previously received pulse, then the bit value detected corresponds to this shortest duration.

According to a particular embodiment, the detection of a first bit is only performed for a transmitter when the duration of the current pulse is greater than or equal to the duration of a pulse from this transmitter.

According to a particular embodiment, when at least one bit has already been assigned to a transmitter, another bit is assigned to the same transmitter if the current pulse forms with the last pulse having allowed an allocation of a bit to this transmitter an interval corresponding to a bit value for this transmitter.

According to a particular embodiment, the detection of a bit is only performed for a transmitter when the duration of the pulse current is greater than or equal to the duration of a pulse in origin of this transmitter.

According to a particular embodiment, if an impulse could not be used to detect a bit, so this pulse is assigned to the first transmitter to which no bit has yet been assigned assigned in decreasing order of pulse durations, said thus assigned pulse used to define the starting point of a bit whose the second pulse will come later.

According to a particular embodiment, if the number of bits assigned to a transmitter is equal to the maximum number of assignable bits for a message, but that nevertheless an additional bit is detected for this transmitter, then the first bit of the message is eliminated, and the last bit detected is added to said message.

According to a particular embodiment, when the pulse current could not be assigned previously and forms with the penultimate pulse stored an interval corresponding to a value of bit for a given transmitter and at least one bit has already been assigned to this transmitter, then the last bit assigned is replaced by the new value detected.

According to a particular embodiment, if an impulse current could not be used before, so we are looking for a transmitter to which a single bit has been assigned and it is determined whether the interval between the current pulse and the first pulse attributed to said audit transmitter corresponds to a bit value for said transmitter, in which case said bit value is retained.

According to a particular embodiment, the parameters of each pulse received is memorized after the analysis of said impulse.

le passage de l'état "Attente de bits supplémentaires" à l'état "Attente de fin de message" se fait lorsque le nombre maximal de bits a été attribué à un émetteur,

le passage de l'état "Attente de fin de message" à l'état "Attente de période de repos" se fait si après une attente d'un temps supérieur à l'intervalle le plus long correspondant à une information pour l'émetteur considéré aucun bit n'a été identifié pour cet émetteur,

le passage de l'état "Attente de période de repos" à l'état "Attente de premier bit" se fait si le temps écoulé depuis le dernier bit reçu (Dernier_temps_i) est supérieur au temps de repos (Trn) de l'émetteur considéré,

le passage de l'état "Attente de bits supplémentaires" à l'état "Attente du premier bit" se fait lorsqu'après l'attribution d'un premier bit, un temps supérieur à l'intervalle le plus long correspondant à une information pour l'émetteur considéré s'écoule sans qu'un bit supplémentaire ne soit détecté.

According to a particular embodiment, the transition from the state "Waiting for first bit" to the state "Waiting for additional bits" is done when a bit has been detected,

the transition from the state "Waiting for additional bits" to the state "Waiting for end of message" takes place when the maximum number of bits has been allocated to a transmitter,

the transition from the state "Waiting for end of message" to the state "Waiting for rest period" is done if after waiting for a time greater than the longest interval corresponding to information for the sender considered no bit has been identified for this transmitter,

the transition from the state "Waiting for rest period" to the state "Waiting for first bit" occurs if the time elapsed since the last bit received (Last_time_i) is greater than the rest time (Trn) of the transmitter considered,

the transition from the state "Waiting for additional bits" to the state "Waiting for the first bit" occurs when after the allocation of a first bit, a time greater than the longest interval corresponding to information for the transmitter in question flows without an additional bit being detected.

des moyens de réception d'un signal résultant de la superposition de signaux émis par au moins deux émetteurs, pour chaque émetteur, les données étant représentées par l'intervalle de temps entre deux impulsions consécutives émises par cet émetteur,

lesdits intervalles de temps ainsi que la largeur des impulsions étant caractéristiques de chaque émetteur,

des moyens d'analyse dudit signal résultant en fonction de la largeur des impulsions détectées dans ledit signal résultant et en fonction des intervalles de temps entre ces impulsions.

The invention also relates to a device for receiving signals, characterized in that it comprises

means for receiving a signal resulting from the superposition of signals transmitted by at least two transmitters, for each transmitter, the data being represented by the time interval between two consecutive pulses transmitted by this transmitter,

said time intervals as well as the width of the pulses being characteristic of each transmitter,

means for analyzing said resulting signal as a function of the width of the pulses detected in said resulting signal and as a function of the time intervals between these pulses.

According to a particular embodiment, the width of the detected pulses is equal or proportional to the width of the pulses emitted by said transmitters.

According to a particular embodiment, said means of reception include an infrared receiver, said transmitters emitting infrared signals and using the same carrier.

According to a particular embodiment, said means include a microprocessor, a memory storing parameters of pulses received, memories storing the bits corresponding to the messages of the various transmitters.

According to a particular embodiment, the device reception implements the method mentioned above.

The invention also relates to an infrared remote control characterized in that it is used in conjunction with a device as described above and in that it comprises means for adjusting the width of the pulses used to represent the data transmitted to said device, said adjustment being carried out so to be unique compared to other remote controls that can be used simultaneously.

According to a particular embodiment, said remote control also includes means for adjusting the time intervals between two pulses used to represent the different data intended to be transmitted.

au moins deux émetteurs, chaque émetteur représentant des données sous la forme d'impulsions de largeur caractéristique dudit émetteur, une donnée étant définie par l'intervalle de temps séparant deux impulsions consécutives émises par cet émetteur, ledit intervalle de temps étant également caractéristique ce chaque émetteur,

un récepteur comportant des moyens de réception du signal résultant de la superposition des signaux émis par lesdits émetteurs,

des moyens d'analyse dudit signal résultant en fonction de la largeur des impulsions détectées dans ledit signal résultant et des intervalles de temps séparant lesdites impulsions.

The invention also relates to a signal reception system characterized in that it comprises

at least two transmitters, each transmitter representing data in the form of pulses of width characteristic of said transmitter, a data being defined by the time interval separating two consecutive pulses emitted by this transmitter, said time interval being also characteristic this each transmitter,

a receiver comprising means for receiving the signal resulting from the superimposition of the signals transmitted by said transmitters,

means for analyzing said resulting signal as a function of the width of the pulses detected in said resulting signal and the time intervals separating said pulses.

According to a particular embodiment, said system sets up implements the process mentioned above.

• les figures 1a et 1b représentent des signaux émis par deux télécommandes suivant un exemple de réalisation de l'invention,
• la figure 1c représente les signaux de la figure précédente tels qu'ils sont perçus par un récepteur,
• la figure 2 est un diagramme-bloc d'un dispositif récepteur mettant en oeuvre le présent exemple de réalisation de l'invention,
• la figure 3 est un diagramme-bloc d'un exemple de télécommande utilisé dans le présent exemple de réalisation,
• la figure 4 est un diagramme d'état d'une pile mémorisant des bits correspondant à un message conformément au présent exemple de réalisation, une pile étant associée à chaque télécommande,
• la figure 5 est un organigramme général du présent exemple de réalisation du procédé utilisé pour acquérir et analyser les données en provenance du récepteur à infra-rouges,
• la figure 6 représente un organigramme d'une première sous-procédure ("Déterminer premier bit") du procédé de la figure 5,
• la figure 7 représente un chronogramme illustrant une configuration particulière des signaux émis par deux télécommandes,
• la figure 8 est un organigramme correspondant à une seconde sous-procédure ("Analyser bit courant") du procédé de la figure 5,
• les figures 9a et 9b représentent ensemble un organigramme d'une troisième sous-procédure ("Vérifier dernier bit") du procédé de la figure 5,
• la figure 10 représente un organigramme d'un procédé ("Attribuer impulsion") utilisé dans la sous-procédure de la figure 9,
• la figure 11a représente une configuration particulière des signaux émis par les télécommandes et pouvant donner lieu à une première erreur corrigée par la sous-procédure de la figure 9,
• la figure 11b représente une configuration particulière des signaux émis par les télécommandes et pouvant donner lieu à une seconde erreur corrigée par la sous-procédure de la figure 9,
• la figure 11c représente une configuration particulière des signaux émis par les télécommandes et pouvant donner lieu à une troisième erreur corrigée par la sous-procédure de la figure 9,
• la figure 12 représente un organigramme d'une procédure ("Faux Départ") utilisée dans l'organigramme de la figure 9,
• la figure 13 représente un organigramme d'une procédure ("Fin de message") utilisé pour déterminer l'interruption ou la fin d'un message.

Other advantages and characteristics of the invention will appear through the description of a particular nonlimiting exemplary embodiment illustrated by the figures among which:

• FIGS. 1a and 1b represent signals emitted by two remote controls according to an exemplary embodiment of the invention,
• FIG. 1c represents the signals of the preceding figure as they are perceived by a receiver,
• FIG. 2 is a block diagram of a receiver device implementing the present exemplary embodiment of the invention,
• FIG. 3 is a block diagram of an example remote control used in the present exemplary embodiment,
• FIG. 4 is a state diagram of a stack memorizing bits corresponding to a message in accordance with the present exemplary embodiment, a stack being associated with each remote control,
• FIG. 5 is a general flow diagram of the present exemplary embodiment of the method used to acquire and analyze the data originating from the infrared receiver,
• FIG. 6 represents a flow diagram of a first sub-procedure ("Determine first bit") of the method of FIG. 5,
• FIG. 7 represents a timing diagram illustrating a particular configuration of the signals transmitted by two remote controls,
• FIG. 8 is a flowchart corresponding to a second sub-procedure ("Analyze current bit") of the method of FIG. 5,
• FIGS. 9a and 9b together represent a flow diagram of a third sub-procedure ("Check last bit") of the method of FIG. 5,
• FIG. 10 represents a flow diagram of a method ("Assign pulse") used in the sub-procedure of FIG. 9,
• FIG. 11a represents a particular configuration of the signals emitted by the remote controls and which can give rise to a first error corrected by the sub-procedure of FIG. 9,
• FIG. 11b represents a particular configuration of the signals emitted by the remote controls and which can give rise to a second error corrected by the sub-procedure of FIG. 9,
• FIG. 11c represents a particular configuration of the signals emitted by the remote controls and which can give rise to a third error corrected by the sub-procedure of FIG. 9,
• FIG. 12 represents a flow diagram of a procedure (“False Start”) used in the flow diagram of FIG. 9,
• FIG. 13 represents a flowchart of a procedure ("End of message") used to determine the interruption or the end of a message.

The description of the particular example contains a reference either to an example of two remote controls, or to a generalization to N remotes, since some explanations will be more clear when only two remote controls are involved.

The particular example described in the following relates to two RC1 and RC2 remote controls, emitting in infrared on the same carrier frequency (e.g. 400 KHz in Europe or 56.8 KHz in United States) and with the same communication protocol. The signals are modulated appropriately on the carrier for transmission. The invention is obviously not limited to infrared transmission.

la durée Tp1 définit la durée d'une impulsion,

la durée T01 entre les fronts actifs de deux impulsions définit la valeur logique "0",

la durée T11 entre les fronts actifs de deux impulsions définit la valeur logique "1",

la durée Tr1 définit la durée de repos ("relax time"), c'est à dire l'intervalle de temps minimal entre deux messages.

FIG. 1a illustrates the coding of messages (or sequences of bits) used by the first remote control RC1. The following four parameters are used to characterize the signals emitted by RC1:

the duration Tp1 defines the duration of a pulse,

the duration T01 between the active edges of two pulses defines the logic value "0",

the duration T11 between the active edges of two pulses defines the logic value "1",

the duration Tr1 defines the rest time ("relax time"), ie the minimum time interval between two messages.

Figure 1b shows similar notations to illustrate the message coding for a second RC2 remote control. So generally, an index n indicates the association with the RCn remote control.

In the present exemplary embodiment, it is assumed that Tp1 <Tp2. It will suffice to classify the remote controls according to the duration of their impulses.

Figure 1c illustrates the signal perceived by an infrared receiver unique. This signal corresponds to the superposition of the signals of the figures 1a and 1b. We see that the first impulse from RC1 is obscured by the first impulse from RC2, while the respective second pulses partially overlap to form a larger impulse.

As we will see in more detail below, the difference between the durations of the pulses of the different remote controls plays a important role in the separation of information from these remote controls.

Figure 2 is a block diagram of a receiving device implementing the present exemplary embodiment. These measures receiver comprises an infrared receiver 1, managed by a circuit of specific reception 2. This circuit 2 provides a signal which, for the following explanations, will be assumed to be similar to that of FIG. 1c. The specific circuit 2 is connected to a processing unit 3, by example a ST90E30 microcontroller manufactured by SGS Thomson. The functions of circuits 1 and 2 are fulfilled for example and not limited to the Sharp GP1U527Y circuit.

According to a particular embodiment, the reception circuit 2 builds on an impulse received from the infrared receiver 1 a pulse of substantially proportional duration. So a duration pulse T from a remote control is perceived as a pulse of duration µT, where µ is a correction coefficient. The relationship between pulses of different duration at the input of the device receiver is thus maintained during signal processing. If the coefficient µ is not precisely known, i.e. if µT is in a range of values, then we will take precautions necessary to avoid overlapping these ranges in adequately choosing the durations of the pulses at the level of transmitters.

The processing unit 3 manages inter alia three random access memories 4 to 6. These memories are shown separately on the diagram, but can physically belong to the same circuit.

The first memory, memory 4, is used to store information from the infrared receiver. Of them information is recorded per pulse: the duration of the pulse (later called Impulsion_mem [i] thereafter), as well as the absolute time of appearance of the active front of this impulse (called Begin_mem [i]). These data are used to characterize the received signal.

According to the present exemplary embodiment, the memory 4 can store the data corresponding to at least 2 * N-1 pulses. She is organized on the principle of the first in last out stack (stack FIFO). The index i has the value 0 for the most recent pulse memorized and increases for older pulses.

The other two memories, 5 and 6, are each assigned to one of the remote controls. Before being stored in memory 4 (the content of this memory making up the history of the signals received), the data is processed by the central processing unit 3, and the result of this analysis, normally corresponding to the identification of a bit information and the identification of the transmitting remote control, is stored in that of the memories which corresponds to the remote control identified. It may be necessary to clear a bit in one of these memories when we later realize that information previous one was poorly analyzed.

Figure 3 shows a block diagram of one of the remote controls. A keyboard 7 is associated with a central unit 8. This last manages in known manner the modulator 9 interface with the diode 10. The central unit is for example a microcontroller Motorola 68HC05C8. An oscillator 11 provides the carrier frequency at the modulator interface 9.

According to a particular variant embodiment, the remote control has on its keyboard means for adjusting the width of the pulses from this remote control and / or time between active edges of two pulses used to code a bit. The adjustment is carried out by placing a switch 12 in a position particular among N positions. The pulse durations Tp, as well as the durations T0i and T1i for the different switch positions are stored in a memory 13 managed by the microcontroller 8. It is so easy to add a remote control in an already existing system in assigning parameters not yet used.

(A)-Attente du premier bit d'un message

(B)-Attente d'un bit supplémentaire d'un message

(C)-Attente de fin de message

(D)-Attente de la durée de repos.

The central unit 3 associates a state and a counter with each of the remote controls. There are four different states:

(A) -Waiting for the first bit of a message

(B) -Waiting for an additional bit of a message

(C) -Waiting for end of message

(D) -Waiting for the rest period.

The counter indicates the number of bits stored in the corresponding memory.

The states and counters are managed by processing unit 3.

Figure 4 illustrates the change from one state to another.

In state A, no bit, therefore no start of message, has yet been detected for a remote control.

In state B, at least a first bit has been received, but the expected number of bits in the message (N_Bits) has not yet been achieved.

N_Bits corresponds for example to 8 bits.

In state C, the expected number of bits has been reached. If a bit additional is detected for this message, an analysis error has been committed previously, and the stored message is changed to result.

In state D, we seek to detect the rest time Trn, minimum time before the next possible message.

For the state associated with remote control n, the transition from state A in state B is done when a bit has been detected for this remote control. The bit counter is then at 1.

The transition from state B to state C occurs when the counter of bits reached N_Bits.

The transition from state C to state D is done if after waiting of a Tan time, such as Tan = max (T0n, T1n), no bit has been identified for this remote control. In the context of this example of realization, Tan = T1n.

The transition from state D to state A occurs when time elapsed since the last bit received is greater than the sleep time Trn.

It is also possible to go from state B to state A, if after reception of the first bit, a Tan time elapses without a another bit is detected for this remote control.

Figure 5 is a flow diagram of the present example of realization of the process used to acquire and analyze the data in from the infrared receiver. The flowchart in Figure 5 is a general organization chart, including the different sub-procedures will be detailed later.

Steps E1 to E4 relate to the acquisition of the parameters characterizing the received signal. A pulse start (rising edge) is detected by the processing unit 3 during the first step. The state of a real time clock is stored in a "Start" variable when step E2. The central unit waits for the end of this pulse (front descending) and determines its duration. (Variable "Duration"). A variable boolean ("Impulse_used") indicates whether or not the impulse could be assigned to a remote control and therefore used to assign a bit.

Remember that the remote controls are classified according to a ascending order of the duration Tpn of the pulses they emit. Unity central will attempt to assign (in the order given and through the steps E5 to E10) a pulse detected at each remote control.

Step E5 is a comparison between the duration of the pulse detected "Duration" and the duration Tpn of the pulse corresponding to the current remote control.

If "Duration" is strictly less than Tpn, then it is certain that this detected pulse cannot be attributed to remote control n. We then go to the next remote control, if necessary (Steps E6 and possibly E7 if all the remote controls have not been switched to review).

In the case of a non-strict superiority, an attribution remains possible. Indeed, the pulse can correspond perfectly to Tpn or be masked in a larger impulse.

The state associated with the remote control n is then tested (Step E8). If this state corresponds to waiting for a first bit (State A), then the central unit implements a first sub-procedure "Determine first bit "(Step E9). If not, we test if the state is waiting from the end of the message (State C). If this is the case, we go to steps E6 and E7, as described above. Otherwise, the analysis of the impulse is carried out at a second sub-procedure "Analyze current bit" (Step E10). The two routines will be seen in detail in connection with FIGS. 6 and 7. Steps E9 and E10 are followed by step E6, which determines whether all remote controls have been reviewed.

If indeed all the remote controls were passed in reviewed, the process goes to step E11. The Pulse used parameter is then tested to know if during one of the two specific routines, it was possible to assign the impulse being analyzed to a remote control or not from the parameters of the current pulse. If not, this means that a bit interpretation error precedent has been committed. This is the role of the third sub-procedure ("Check last bit", step E12) than correcting this anomaly.

Once steps E11 and E12 have been completed, the parameters of the current pulse are stored in memory 4.

The "Determine first bit" sub-procedure is illustrated by the flowchart of figure 6. This sub-procedure is implemented for a remote control n when the status associated with this remote control is that of waiting for the first bit and that a priori, the duration of the pulse that we just received is such that a pulse of duration Tpn corresponding to the remote control could not be included.

The principles used by this sub-procedure are: following: The duration of T0N being less than the duration T1N in the this example, we first try to determine if the beginning of the current pulse can, in combination with a pulse previously stored in memory 4, form a "0" which can be a first bit in the sense of remote control n. This is achieved by steps E101 to E109. If a "0" is not detected, then we seek to determine the presence of a "1". This is achieved by steps E111 to E118.

So it's not just the most recent impulse that we are trying to analyze, this one not yet stored in the memory 4. As part of the routine "Determine first bit", we is mainly interested in the rising edge of this most impulse recent. To form a bit, two pulses are necessary.

Steps E119 to E121 correspond to the treatment of a case particular according to which one chooses to recognize a "0" while the normal conditions for this recognition are not quite fulfilled. This particular case, illustrated by Figure 7, is followed through the value of a variable called "PossibleZero". A null value of this variable indicates that we are not in the particular case. It's at this value that we initialize the variable.

Subsequently, we can clearly distinguish the duration of a pulse (Tpn) the duration of a bit (T0n or T1n).

Step E101 concerns the initialization of the verification of the presence of a "0". We systematically analyze each memorized pulse, starting from the most recent (index i = 0). It is recalled that the data stored in the memory 4 makes it possible to determine the duration of a pulse, as well as the moment of appearance of his rising forehead.

If the duration of the pulse i is strictly less than Tpn, this pulse could not be sent by the remote control n, the pulse being too short (E102). In this case, we go to the next pulse (E106). If, on the other hand, a pulse of duration Tpn can be contained in pulse i, then the duration of the corresponding bit is determined. This duration (called Duration_bit) is made up of the difference between the moment of appearance of the rising edge of the current pulse (Variable Start) and the moment of appearance of the rising edge of the pulse i (Variable Begin_mem [i]) (Step E103).

If this duration is not equal (to within an error range and which processing unit 3 always takes into account during comparisons) to the duration of a bit "0" for this remote control n, then the pulse is rejected and the next pulse is analyzed (Steps E104, then E106 and E107). On the other hand if we have the equality between T0n and Runtime_bit, then we still check if the pulse started in a relaxation interval Trn (E105).

If so, the impulse is rejected and the search is continued by incrementing i (E106).

If not, check whether the duration of the pulse i is equal (always within an error range) to the duration of a pulse of the remote control n (Step E108). If this condition is true, then a "0" is identified (Step E109). If this equality is not checked, this meaning in this case that the duration of the pulse i is strictly greater than T0n, it is possible, but not compulsory, that a front pulse corresponding to a "0" is masked by a pulse of greater width. The variable "Possible Zero" is then set to 1 and a search for a "1" is launched (Step E111).

The timing diagram in Figure 7 illustrates the special case that one wishes to solve thanks to this mechanism. The first line of this figure corresponds to the first bit sent by a first remote control, whose pulses have a duration Tpa shorter than that Tpb of a second remote control, one of which is illustrated by the second line of figure 7. The intervals T1a and T0a correspond to the durations bits for the first remote control.

If a pulse A from the second remote control is inserted between two pulse edges B and C of the first remote control so that what the time interval between the front of A and the front of C corresponds to T0a, an absence of test on the duration of the pulse A (step E108) would have the effect of detecting a 0.

This is not a problem if the impulse A effectively masks an impulse from the first remote control, but is annoying when a "1", longer than "0", must be detected, such as this is illustrated in figure 7. It is for this reason that we seek to detect the presence of a "1". If this detection is not carried out at from the contents of memory 4 and that the variable "PossibleZero" is true, then a "0" is detected.

The detection of a "1" is quite similar to the detection with a "0". Steps E101 to E107 correspond to steps E111 to E117. The correction mechanism implementing the step of comparison E108 is not used for the detection of a "1". The test step E115 (corresponding to step E108) leads directly to the recognition of a "1" (step E118).

When all the possibilities of detecting a "1" have been exhausted without success (test of step E117 verified), the state of the variable "PossibleZero" is tested, and a bit "0" recognized if this variable is 1. If the test is negative, then we exit the routine directly by through step E122.

Following the three cases where a bit "0" or "1" was recognized, a a number of parameters need to be updated (E110). The first parameter is the bit counter N_bits_n associated with remote control n. This counter must be set to 1, meaning that at this time, a first bit has been detected for this remote control.

On the other hand, the state (State_n) associated with the remote control changes: from the waiting state for the first bit (A), we go to the waiting state for bits additional (B).

In addition, it was possible to assign the last memorized bit. The variable Impulsion_used is therefore set to true.

Finally, we store in the variable Last_time_n the moment identifying the rising edge of the current pulse ("Start").

After this update, we also proceed to the step E122.

Let us return now to the general flowchart of figure 5. Suppose that the state associated with the remote control was not the state waiting for the first bit during step E8. We then test whether this state corresponds to waiting for additional bits. This is for example the case when a bit has already been detected previously for the remote control n. If this test is positive, then a specific analysis is performed in step E10 to determine if, from the pulses stored in memory 4 and with respect to the rising edge of the current pulse, a bit "0" or "1" can be assigned to the remote control n.

Figure 8 is a flowchart corresponding to the routine "Analyze current bit".

When this routine is addressed for remote control n, it is certain that the state of this remote control is the bit wait state additional. In this case, at least one bit has already been allocated to this remote control n and has been stored in the correct memory. On the other hand, we know through the variable Last_weather_n to when was the rising edge of the last pulse detected used to assign the most recent bit stored in memory. It is from this information and from the moment of the arrival of the front amount of the current pulse that we determine the bit duration Duration_bit (Step E201). The other steps are to determine if this bit can correspond to an additional bit from the remote control n.

We first compare the bit duration Duration_bit to the duration T1n of a logic "1" for the remote control 1, this indeed obviously with some error (E202). If both durations correspond, then a logical "1" is identified and inserted in the battery associated with remote control n (Step E203).

If a "1" is not identified, then the bit duration is compared at T0n (E204). If the two durations match, a logical "0" is identified and stored in the corresponding memory (Step E205).

After identifying either a logical "1" or a logical "0", the bit counter N_Bit_n is incremented, the variable Last_time_n is update and the fact that the current pulse was used is memorized by setting the Pulse variable used to 1 (Step E208).

It is then determined whether the message received and stored contains the maximum number of bits, namely N_Bits (E210). If so, the state associated with the remote control n becomes the end of message waiting state (E209). If this is not the case, or after the change of state, the process of FIG. 5 is repeated (E211).

If the tests in steps E202 and E204 were negative, a third test is undertaken in step E206. If the bit duration Duration_bit is strictly greater than T1n (which represents, between T0n and T1n and according to this embodiment the longest duration), then the bit duration cannot correspond to a bit from the remote control n. It is then assumed that the message from the remote control n has been interrupted. The state associated with the remote control n returns to the state waiting for the first bit (E207) and the corresponding memory is cleared. The Impulse_attribue_n variable is also set to 1 to indicate that the remote control n received its first impulse (but not yet its first bit, which is determined by two pulses).

If the test in step E206 proves negative, then the method of Figure 5 is repeated (E211).

Returning to Figure 5, we see that all of the steps E5, E8, E9, E10 and E14 is repeated for each remote control.

In case of negative test in step E5, in case of positive test in step E14 or after the two routines described above, we determine if the index n corresponds to its maximum N (E6). If not, the index is incremented (E7) and step E5 is repeated.

Once all the remote controls have been reviewed, we determines if the current pulse has been used to assign a bit to one of the remote controls (E11). If not, assume that an interpretation error was made for a bit previously stored in one of the memories.

It is the function of the third routine (E12) to correct this misinterpretation. Subsequently, the parameters relating to this pulse are stored in memory 4 (E13).

The main course of this stage is illustrated by the flow chart consisting of Figures 9a and 9b.

First, a step E301 makes it possible to verify whether the current pulse is the first pulse of a message sent by one of the remote controls. This pulse was not used during one of the two sub-procedures E9 or E10 for the allocation of a bit. The first pulse assigned to a remote control does not allow to assign a bit, since a bit is defined by the interval of time between two successive pulse edges. The use of variable "Impulsion_attribégé_i" allows to assign an impulse to a only remote control whose state is "Waiting for the first bit".

Step E301 thus makes it possible to avoid certain cases of correction later.

Step E301 is described in detail by the flowchart in Figure 10.

For each remote control, the following steps are carried out:

We first check if the state associated with the remote control is the waiting state for the first bit (E401). If not, we go to the following remote control, via the E402 / E406 loop (step E407 used to initialize this loop). If so, checks if the duration Tp of the pulse is such that it corresponds to the duration a pulse from the remote control currently being processed or if it can hide such an impulse (E403). If the result of the comparison is negative, then the same goes to the next remote control. In the case of a positive comparison, we check if an impulse has already been assigned to this remote control (E404).

The same remote control can only have one starting impulse. This state of affairs is memorized by the variable Impulse_attribégé_i. If this variable indicates that a pulse has already has been assigned (i.e. according to the present example if it has the value 0), then we conclude that the pulse currently processed does not does not come from the remote control in question and we pass if necessary to the next remote control (E404). On the other hand, if no impulse has assigned to the remote control in question, so the pulse is assigned (E405). The pulse is then marked as having been used. On the other hand, the variable Impulse_attribue_i is set to 1 for indicate that an impulse has been assigned to the remote control i. If one allocation has taken place, then the process of FIG. 10 is terminated.

The loop of step E301 works by decreasing values of the pulse duration Tpi. In this way, the impulse will be attributed to the most likely remote control.

Once the process of Figure 10 is completed we return to process of figure 9. Since any impulse comes from a n remote controls, if no allocation could be made during from step E301, it is concluded that there has been a misinterpretation of a previous impulse. In this case, a deeper analysis is performed for remote controls with which have already been associated bits.

Three cases should be considered, illustrated respectively by the Figures 11a, 11b and 11c.

In a first configuration, we are interested in remote controls whose associated status is "Waiting for end of message" (C). It is then determined whether the current pulse could form a "0" or a "1" with a pulse previously assigned to these remote controls. If this is indeed the case, then we assume that the first bit of the message from the remote control was incorrectly assigned. This first bit is eliminated, while the new bit is added at the end of the message. The Figure 11a illustrates a configuration of the signals from remote controls that can cause such an error.

The first line of figure 11a corresponds to the signals emitted by a first remote control, while the second line of this figure corresponds to the signals emitted by a second remote control. Pulse B corresponds to the first pulse sent by the first remote control. Pulse A emitted by the second remote control is such that the time interval between its rising edge and the rising edge of a pulse B emitted by the first remote control correspond to time T01. The routine "Determine first bit "as described above will detect a" 0 "for the first remote control during the analysis of pulse B. A bit is therefore detected before the actual start of the message. This is due to the fact that a first remote control pulse could be hidden by pulse A, wider.

In this case, this first bit detected should be eliminated, shift the whole message and add a "0" or a "1", depending on the bit detected by analysis of the most recent pulse.

This first configuration is detected when the state associated with a remote control is "Waiting for end of message" but an additional bit is nevertheless detected for this remote control.

According to a second configuration illustrated in FIG. 11b, the rising edge of a pulse from the first remote control (pulse D) forms with the rising edge of a consecutive pulse of the second remote control (pulse E) a bit "0" for the first remote control. The analysis performed by the routine "Analyze current bit" (the status associated with the remote control is "Waiting for bits additional ") is such that a bit" 0 "will be associated with the first remote control. However, if the pulse E does not mask the pulse emitted by the first remote control is that the rising edge of the pulse F emitted by the first remote control forms a "1" with the rising edge of pulse D. A "0" would therefore be detected instead of a "1".

This correction is close to that made at step E119 of FIG. 6, but the sub-procedure of FIG. 6 does not concerns that the detection of a first bit, while in the case present, the state associated with a remote control may be different from the state "Waiting for the first bit".

According to a third configuration illustrated in FIG. 11c, a "0" may be detected at the wrong time. Suppose that the fronts of two pulses emitted by a first remote control (G pulses and H) form a "0". As already mentioned, the test carried out to determine if the duration of a bit corresponds to T0i takes into account a error ± Δ which constitutes a range around the value T0i. Yes the time interval between the rising edge of a pulse I emitted by a second remote control and the rising edge of the pulse G falls within the range thus determined, then a "0" can be detected. The value "0" is not in itself false, since in any case, the pulses G and H give the same information. However, the variable "Last_time_i" would contain a false value, which would have consequently a possible misinterpretation of the following bits.

This third configuration also applies to the erroneous detection of bits at "1".

The correction made for the second and third configuration consists, during the analysis of the pulse F, in checking whether this impulse gives consistent information for a remote control given in connection with the penultimate bit. If this information corresponds to a "1" or a "0", the last bit assigned to this remote control is replaced by this information.

Let's go back to figure 9 to see in more detail the process used. The step E301 is now taken and we test during a step E302 if the impulse could be assigned during step E301. In if so, the three configurations explained above do not take place to be corrected, and the routine ends (E303).

As before, a loop (made through steps E304, E305 and E306) reviews the different remote controls.

Firstly (E304), it is determined whether the pulse in analysis course is the same as or is such that it can hide a pulse from the remote control i. If it's not the case, we go to the next remote control by incrementing the index of remote controls (step E306). If so, the duration is determined bit (Variable Bit Duration) corresponding to the time interval between the rising edge of the pulse being analyzed and the last edge amount memorized for the remote control, namely Last_time_i.

First, we test through the steps E309 to E313 if you are in the first configuration (figure 11a) described above. For this, we first seek to know if the associated state on the examined remote control is indeed "Waiting for end of message". If this is not the case, we go to the verification of the corresponding conditions in the second and third configurations. If so, the steps E310, respectively E312 test whether the bit duration corresponds to a "1" or a "0". If one of the two tests is positive, then the message registered for the remote control being examined is shifted and a "1" or "0" is added respectively (steps E311 and E313). The impulse thus used, the routine ends at step E303, after the pulse the most recent was marked as having been used.

If the first configuration could not be detected or if the status associated with the remote control is "Waiting for additional bits" (Test E314), then we determine if the conditions of the second or third configuration (Figures 11b and 11c) are met.

The value of the last bit memorized for the examined remote control (E316). We calculate the time interval separating the rising edge of the pulse being analyzed (for example rising edge of the pulses F or H of FIGS. 11b and 11c and of which the time of appearance is memorized by the Start variable) and the front amount of the penultimate pulse stored (for example pulses D or G of Figures 11b and 11c). This calculation is performed in calculating the time interval between Duration and Last_Time_i, and by adding T0i or T1i according to the value of the last bit memorized (steps E317, respectively E318).

Then we compare this time interval to the duration of a bit "0" and "1" for the currently examined remote control (durations T0i and T1i in steps E319 and E320). If one of these durations corresponds to the previously calculated time interval, then the last bit stored for the remote control is erased and replaced by the new value determined. In addition, the parameter indicating the last rising edge of an impulse that gave rise to the allocation of a bit to the remote control is updated (Last_time_i parameter).

If after the examination corresponding to the three configurations cited, an impulse could not be attributed to any remote control, then an additional routine, called "Erroneous departure" is launched. This routine (E321) is only executed for remote controls to which a first bit has been assigned, and it resumes the routine "Determine first bit" previously described. The organization chart figure is shown in Figure 12.

Returning to the main flowchart in Figure 5, there remains still to validate the stored messages if necessary, or to determine if these messages were interrupted during transmission.

Figure 13 gives the flowchart of the corresponding process (called "End of message") according to the present exemplary embodiment. This procedure is launched when no pulse is detected (step E1). It is also possible to launch it at another time.

As before, a loop is created to pass in review all the remote controls (steps E501, E502 and E503).

For each remote control, the elapsed time is determined from the rising edge of the last pulse attributed to this remote control by making the difference between the clock state of the system and the parameter Last_time_i (Step E504). We then test (E505) if this duration is greater than the longest bit duration for this remote control (in this case T1i according to the present example). Yes this is not the case, we go to the next remote control (E502). In indeed, a pulse intended for the remote control can still reach the receiver. There is therefore no reason to terminate the message received, it not necessarily complete or correct.

If on the other hand the test of step E505 proves positive, a priori no future impulse can be attributed to the remote control considered. Depending on the state of the message, it is then considered to be complete or as discontinued. We first determine if the state of the message is the waiting state for message end or not (E506). If this is not the case, then we check (E507) if the time elapsed since the last pulse assigned to the remote control is greater than the time of this remote control. If it is, then the message is considered interrupted and the state of the message is reset waiting for the first bit (E508). If the duration is less than the rest we go to the next remote control (E502).

If the state of the message is indeed the waiting state at the end of message, then this state is changed while waiting for the rest time (E508). The message is then considered complete and can be analyzed from otherwise known manner for determining its meaning (E509). When of a subsequent resumption of the process of FIG. 13, the state of the message will be returned to the waiting state of the first bit, thus authorizing reception of a new message.

The embodiment described describes a multitude of fixes for various signal configurations. According to complexity desired device and treatment performed, some corrections can, according to an alternative embodiment, be eliminated. This risks to be detrimental to performance but will simplify the treatment.

Finally, although the exemplary embodiment relates to a coding of values of a bit, two time intervals (T0i and T1i) being used, the invention is not limited to such coding.

The applications of the invention are numerous: video games or interactive television, control of multiple devices through a single control signal receiver using multiple remote controls, etc ...

Claims (25)

1. Process for receiving signals emanating from at least two transmitters (RCi), characterized in that,

   for each transmitter, the data (0, 1) being represented by the time interval (T0i, T1i) between two consecutive pulses transmitted by this transmitter,

   the said time intervals as well as the width of the pulses (Tpi) being characteristic of each transmitter,

   the said process comprising the steps:

   of receiving a signal resulting from the superposition of the signals transmitted by the said transmitters,

   of determining the parameters of the pulses of the said resulting signal, the said parameters comprising the width of the pulses as well as their spacing,

   of allocating a datum to a transmitter as a function of the these parameters.
2. Process according to one of Claims [sic] 1, characterized in that the data are the two possible values of a bit.
3. Process according to Claim 2, characterized in that a datum representing the state of a message emanating from each transmitter is associated with this transmitter.
4. Process according to Claim 3, characterized in that the state of the message is standby for a first bit of a message (A), standby for additional bits (B), standby for the end of the message (C) or standby for the end of the quiescent time between two messages (D).
5. Process according to one of Claims 2 to 4, characterized in that a first bit is detected for a given transmitter when the time interval (Duration_bit) between the current pulse and one pulse from among the pulses previously received (Start_mem[i]) is equal to one of the intervals (T0i, T1i) defining a bit value for the said transmitter and that the duration (Duration_mem[i]) of the said pulse from among the pulses previously received is equal to the duration (Tpi) of a pulse associated with the said given transmitter.
6. Process according to Claim 5, characterized in that the comparison between the time interval (Duration_bit) between the said two pulses and the intervals defining a bit value for the said transmitter is performed via increasing intervals defining a cue (T0i, T1i), all the pulses previously received and stored (Start_mem[i], Duration_mem[i]) being scrutinized for each of the intervals defining a bit value.
7. Process according to Claim 6, characterized in that the intervals defining a bit value (T0i, T1i) being two in number, if no bit is detected but there was equality between the shortest duration corresponding to a bit value (T0i) and the time interval (Duration_bit) separating the current pulse and a pulse previously received, then the bit value detected corresponds to this shortest duration (T0i).
8. Process according to one of Claims 5 to 7, characterized in that the detection of a first bit is carried out for a transmitter only when the duration of the current pulse (Duration) is greater than or equal to the duration (Tp) of a pulse originating from this transmitter.
9. Process according to one of Claims 2 to 8, characterized in that when at least one bit has already been allocated to a transmitter, another bit is allocated to the same transmitter if the current pulse forms together with the last pulse having allowed a bit to be allocated to this transmitter an interval corresponding to a bit value for this transmitter.
10. Process according to Claim 9, characterized in that the detection of a bit is carried out for a transmitter only when the duration of the current pulse (Duration) is greater than or equal to the duration (Tp) of a pulse originating from this transmitter.
11. Process according to one of Claims 5 to 10, characterized in that if it has not been possible to use a current pulse to detect a bit (Pulse_used), then this pulse is allocated to the first transmitter (i) to which no bit has yet been allocated in decreasing order of pulse durations (Tpi), the said pulse thus allocated serving to define the start point of a bit whose second pulse will arrive later.
12. Process according to one of Claims 5 to 11, characterized in that if the number of bits (N_bits_i) allocated to a transmitter is equal to the maximum number (N_bits) of bits which can be allocated to a message, but if nevertheless an additional bit is detected for this transmitter, then the first bit of the message is eliminated, and the last bit detected is appended to the said message.
13. Process according to one of Claims 5 to 12, characterized in that when it has not been possible for the current pulse to be allocated to a transmitter and the current pulse forms together with the penultimate pulse stored an interval corresponding to a bit value for a given transmitter and when at least one bit has already been allocated to this transmitter, then the last bit allocated is replaced by the new value detected.
14. Process according to Claim 13, characterized in that if it has not been possible for a current pulse to be used previously, then one searches for a transmitter to which a single bit has been allocated and one determines whether the interval between the current pulse and the first pulse allocated to the said transmitter corresponds to a bit value for the said transmitter, in which case the said bit value is retained.
15. Process according to one of Claims 5 to 14, characterized in that the parameters (Duration, Start) of each pulse received are stored (Duration_mem[i], Start_mem[i]) after the analysis of the said pulse.
16. Process according to one of Claims 4 to 15, characterized in that

    the switch from a Standby for first bit state to a standby for additional bits state is made when a bit has been detected,

    the switch from a "Standby for additional bits" state to a standby for end of message state is made when the maximum number of bits has been allocated to a transmitter,

    the switch from a standby for end of message state to a standby for quiescent period state is made if after a standby for a time greater than the longest interval corresponding to a cue for the transmitter considered no bit has been identified for this transmitter,

    the switch from the standby for quiescent period state to the "standby for first bit" state is made if the time elapsed since the last bit received (Last_time_i) is greater than the quiescent time (Trn) of the transmitter considered,

    the switch from the standby for additional bits state to the standby for the first bit state is made when, after allocating a first bit, a time greater than the longest interval corresponding to a cue for the transmitter considered elapses without an additional bit being detected.
17. Device for receiving signals, characterized in that it comprises

    means (Fig. 2; 1, 2) for receiving a signal (Rec) resulting from the superposition of signals transmitted by at least two transmitters (RC1, RC2), for each transmitter, the data (0, 1) being represented by the time interval (T0i, T1i) between two consecutive pulses transmitted by this transmitter,

    the said time intervals as well as the width of the pulses (Tpi) being characteristic of each transmitter,

    means (3, 4, 5, 6) for analysing the said resulting signal as a function of the width (Pulse_mem[i], Duration) of the pulses detected in the said resulting signal and as a function of the time intervals between these pulses.
18. Device according to Claim 17, characterized in that the width of the pulses detected is equal or proportional to the width of the pulses transmitted by the said transmitters.
19. Device according to one of Claims 17 or 18, characterized in that the said reception means comprise an infrared receiver (Fig. 2; 1, 2), the said transmitters (RC1, RC2) transmitting infrared signals and using the same carrier.
20. Device according to one of Claims 17 to 19, characterized in that the said means of analysis comprise a microprocessor (3), a memory (4) storing parameters of pulses received (Pulse_mem[i], Start_mem[i]), memories (5, 6) storing the bits corresponding to the messages of the various transmitters.
21. Device according to one of Claims 17 to 20, characterized in that it implements the process according to one of Claims 1 to 16.
22. Infrared remote control (RC1, RC2) characterized in that it is used in conjunction with a device according to one of Claims 17 to 21 and in that it comprises means (12) for adjusting the width of the pulses used to represent the data sent to the said device, the said adjustment being performed in such a way as to be unique with respect to other remote controls which can be used simultaneously.
23. Remote control according to Claim 22, characterized in that it also comprises means (21) for adjusting the time intervals between two pulses serving to represent the various data (0, 1) intended to be sent.
24. System for receiving signals, characterized in that it comprises

    at least two transmitters (RC1, RC2), each transmitter coding data in the form of pulses of characteristic width (Tpi) of the said transmitter, a datum being defined by the time interval (T0i, T1i) separating two consecutive pulses transmitted by this transmitter, the said time interval also being characteristic of each transmitter,

    a receiver comprising means (Fig. 2; 1, 2) for receiving the signal resulting from the superposition of the signals transmitted by the said transmitters,

    means (3, 4, 5, 6) for analysing the said resulting signal as a function of the width of the pulses detected in the said resulting signal and as a function of the time intervals separating the said pulses.
25. System according to Claim 24, characterized in that the said transmitters comprise a remote control in accordance with one of Claims 22 or 23.

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