Abstract:
A pulsed electrical remote control interface for an equipment item including a plurality of functions to be controlled includes at least a first command input associated with a first command line (TC-Type, TC-Type-plus, TC-Type-minus) for selecting at least one function (RF ON, RF OFF, ALC ON, ALC OFF, FCA UP, FCA DOWN, GCA UP, GCA DOWN, SCA UP, SCA DOWN, INHIBIT) to be performed from the plurality of functions and at least one second command input associated with a second command line (EXE, EXE-UP-ON, EXE-DOWN-OFF) for executing the selected function, each command input being associated with an outbound pulsed command line and a return line, the return line possibly being shared with a number of outbound lines. Applicable to the control of any kind of equipment that includes a large number of functions and requires a large number of pulsed command signals, notably in the field of satellite communication systems.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a pulsed electrical remote control interface, an equipment item and a satellite including such an interface. It applies to the control of any kind of equipment that includes a large number of functions and requires a large number of pulsed command signals, such as, for example, linearized driver limiter amplifiers LDLA used in satellite communication systems. 
       BACKGROUND OF THE INVENTION 
       [0002]    In satellite communication systems, some equipment such as the power amplification subsystems are becoming increasingly complex with a growing need for remote control signals. For example, the DLA (driver limiter amplifier) function and the power flexibility function of the travelling wave tube amplifiers TWTA require a growing number of pulsed commands for their configuration. This need for additional commands does not involve any complication for remote controls that have an interface of serial type, such as a 16-bit serial command for example, but is very detrimental for pulsed remote controls because they require additional command lines. In practice, currently, controlling an LDLA entails applying ten pulsed commands via ten dedicated interfaces. This large number of commands increases the complexity of the remote control systems and affects the cost and weight budget of the equipment and of the electrical leads that are fitted on the platforms of the satellites as much as in the current satellite applications; for each function to be controlled, each electrical control interface consists of a wired link comprising an outbound command line and an associated return line, but it is often accepted that several outbound command lines have one command return line. Furthermore, the current electrical control interfaces have the additional drawback of not allowing a command sent in error to be cancelled. 
       SUMMARY OF THE INVENTION 
       [0003]    The aim of the invention is to resolve these problems and propose a pulsed electrical remote control interface that makes it possible to limit the number of command lines regardless of the number of functions to be driven and that makes it possible to cancel a current command. 
         [0004]    For this, the invention relates to a pulsed electrical remote control interface for an equipment item including a plurality of functions to be controlled, said electrical interface comprising at least a first command input associated with a first command line for selecting at least one function to be performed from the plurality of functions and at least a second command input associated with a second command line for executing the selected function, each command input being associated with an outbound pulsed command line and a return line, the return line possibly being shared with a number of outbound lines. 
         [0005]    Advantageously, each function to be controlled is defined by a predetermined number of consecutive command pulses. 
         [0006]    According to one embodiment of the invention, the number of command pulses is different for different functions and the electrical interface has only two command inputs respectively dedicated to selecting at least one function and executing the selected function. 
         [0007]    According to another embodiment of the invention, the number of command pulses is identical for functions of the same type corresponding to a first direction or to a second direction of execution that are different and the electrical interface includes at least one selection command input and two execution command inputs respectively dedicated to the execution of the selected function in the first direction and in the second direction. 
         [0008]    According to another embodiment of the invention, the electrical interface includes two selection command inputs and two execution command inputs, the two selection command inputs being respectively dedicated to increasing and reducing a number of pulses counted, the number of pulses counted corresponding to the selection of the function. 
         [0009]    Preferentially, on the execution command inputs, each command for executing a function comprises a single pulse. In this case, advantageously, the performance of the same function several times in succession corresponds to the emission of a number of consecutive pulses on the same command input. 
         [0010]    Advantageously, the execution command pulse for a function selected by the selection command inputs is emitted on an execution command input after the emission of the pulses for selecting the function on a selection command input. 
         [0011]    The invention also relates to an equipment item that includes an electrical remote control interface according to the invention and a satellite that includes at least one equipment item according to the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Other particular features and advantages of the invention will become clearly apparent hereinafter from the description given by way of purely illustrative and nonlimiting example, with reference to the appended diagrammatic drawings which represent: 
           [0013]      FIG. 1 : an exemplary electrical remote control interface for an equipment item, according to the prior art; 
           [0014]      FIG. 2 : an exemplary sequence of pulsed command signals for an equipment item, according to the prior art; 
           [0015]      FIG. 3 : an exemplary electrical remote control interface for the equipment of  FIG. 1 , comprising three command inputs, according to a first embodiment of the invention; 
           [0016]      FIG. 4 : an exemplary sequence of pulsed command signals for the equipment of  FIG. 1 , corresponding to the performance of the same successive functions as in  FIG. 2 , according to the first embodiment of the invention; 
           [0017]      FIG. 5 : an exemplary electrical remote control interface for the equipment of  FIG. 1 , comprising two command inputs, according to a second embodiment of the invention; 
           [0018]      FIG. 6 : an exemplary sequence of pulsed command signals for the equipment of  FIG. 1 , corresponding to the performance of the same successive functions as  FIGS. 2 and 4 , according to the second embodiment of the invention; 
           [0019]      FIG. 7 : an exemplary electrical remote control interface for the equipment of  FIG. 1 , comprising four command inputs, according to a third embodiment of the invention; 
           [0020]      FIG. 8 : an exemplary sequence of pulsed command signals for the equipment of  FIG. 1 , corresponding to the performance of the same successive functions as  FIGS. 2 ,  4  and  6 , according to the third embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]      FIG. 1  represents an exemplary remote control interface for an equipment item onboard a satellite, according to the prior art. The interface comprises ten command inputs corresponding to ten pulsed commands, each command input being associated with an outbound pulsed command line and a return line. However, for some applications, the return line may be common to a number of outbound lines. In this example, the command inputs of the remote control interface are linked to a control unit, for example a computer, onboard a satellite and the output signals from the control interface are transmitted to an equipment item comprising, for example, a linearized driver limiter amplifier LDLA. To control the linearized driver limiter amplifier LDLA, two command inputs RF ON and RF OFF are needed to respectively control the emission of a radiofrequency signal and stop this emission. Similarly, two command inputs ALC ON and ALC OFF (ALC standing for automatic level control) are needed to execute the commands of the ALC function in ALC mode corresponding to the ALC ON command or in fixed gain mode FGM, corresponding to the ALC OFF command and three times two command inputs UP, DOWN are needed to execute each of the gain commands FCA UP and FCA DOWN (FCA standing for flux control attenuator), adjust the amplitude GCA UP and GCA DOWN (GCA standing for gain control attenuator) and control a linearizer SCA UP and SCA DOWN (SCA standing for setting control attenuator). Each function requires two specific command inputs respectively associated with two specific command lines making it possible to determine the direction of execution of the selected function, that is to say, determine whether the function must be activated in a first direction ON or UP or in a second direction OFF or DOWN. The greater the number of functions to be performed, the greater the number of command inputs and command lines, the number of command lines being twice the number of functions to be performed. Furthermore, this system does not make it possible to cancel a command; when the command pulse is emitted, the command is systematically executed. As represented in  FIG. 2 , the execution of each function is performed by the emission of a pulse to the command input corresponding to this function and the emission of several successive pulses to one and the same command input corresponding to the execution of the same function several times in succession. Furthermore, in case of an error, after the emission of a pulse to one of the command inputs, there is no possibility of cancelling the execution of that function since each pulse emitted to a command input triggers the execution of the function corresponding to that command input. The sequencing represented in  FIG. 2  corresponds to the execution of the plurality of the following different types of functions: RF-OFF, RF-ON, GCA-DOWN (reduction=2), ALC-ON, SCA-UP (increase=2), FCA-DOWN (reduction=4), FCA-UP (increase=1). The INHIBIT function corresponding to the cancellation of a command pulse that has already been emitted is impossible. 
         [0022]    To limit the number of command inputs and associated command lines regardless of the number of functions to be driven and allow a command to be cancelled in the case of an error, the invention consists, in a first and a second embodiment, in allocating to one and the same command input a number of pulses specific to each function, which makes it possible, by a countdown of the number of pulses emitted, to select the type of function to be performed by using the same command line regardless of the function selected and use only one or two other additional command inputs to launch the execution of the selected function. 
         [0023]    Alternatively, to reduce the number of pulses emitted to the command input for selecting the type of function, it is also possible to use additional selection command inputs as indicated by way of example in the third embodiment of the invention. 
         [0024]      FIG. 3  represents an exemplary electrical remote control interface for the same LDLA equipment as that of  FIG. 1 , according to a first embodiment of the invention. The electrical interface comprises a maximum of three command inputs, each command input being associated with an outbound pulsed command line and a return line. 
         [0025]    The first command line, called TC-Type, applied to the first command input is made up of signals intended to select at least one type of function to be performed from the plurality of functions that are possible, RF, ALC, FCA, GCA, SCA. The five types of command functions for the LDLA equipment are complemented by a sixth function, called INHIBIT command, corresponding to the cancellation of the last command emitted and not yet executed. 
         [0026]    The second command line, called EXE-ON-UP, applied to a second command input, consists of a signal for activating the selected function in a first direction, ON or UP. The third command line, called EXE-DOWN-OFF, applied to the third command input consists of a signal for activating the selected function in a second direction, OFF or DOWN. The signal for activating a function selected by the first command line TC-Type is emitted over the second or third command line EXE-UP-ON, EXE-DOWN-OFF after the emission of the function selected on the first command line TC-Type. 
         [0027]    As represented in  FIG. 4 , according to this first embodiment of the invention, each type of function is defined by a predetermined number of consecutive command pulses, this number of pulses being different for each type of function. Thus, a given number of consecutive pulses has a corresponding single type of function to be executed. The number of pulses on the TC-Type line is unlimited and is chosen according to the requirements and constraints such as, for example, reliability constraints and/or constraints on the number of functions to be controlled. The width of the pulses and the interval between the pulses are chosen freely and are limited only by the operational or technological constraints. In this example, the selection of the RF ON/OFF function corresponds to a command signal comprising a single pulse, the selection of the ALC ON/OFF function corresponds to a signal with two consecutive pulses, and the selections of the FCA, SCA and GCA functions correspond to command signals respectively comprising three, four and five consecutive pulses. The selection of the INHIBIT function corresponds to a number of pulses greater than the number of pulses of all the other commands. For example, in the case of  FIG. 4 , the selection of the INHIBIT function corresponds to a signal comprising a number of pulses greater than or equal to 6 consecutive pulses. 
         [0028]    The activation signals EXE-ON-UP and EXE-DOWN-OFF for the selected functions can, for example, comprise a single pulse for the ON or OFF direction commands and for the UP and DOWN direction commands. In this case, the performance of the same function several times in succession corresponds to the emission of several consecutive pulses over the same line EXE-UP-ON or EXE-DOWN-OFF. For example, in  FIG. 4 , the two consecutive pulses on the EXE-UP-ON line corresponding to the TC-Type SCA function mean that the SCA function must be executed twice in the UP direction which corresponds to an increase by two units of the SCA function. The delimiting of the commands applied to the TC-Type command line is then performed by the first pulse which arrives on the EXE-UP-ON or EXE-DOWN-OFF line after the selection of the function on the TC-Type line. The countdown of the pulses emitted to the selection command input is performed by the electrical remote control interface and is reset after the execution of each function. 
         [0029]    In one and the same TC-Type command line, this protocol makes it possible to sequence, at will, a plurality of executions of different types of functions, as represented for example in  FIG. 4 . The sequencing of the functions represented in  FIG. 4  is the same as that represented in  FIG. 2 , apart from the INHIBIT function, and corresponds to the following functions: RF-OFF, RF-ON, GCA-DOWN (reduction=2), INHIBIT (cancellation of the current command), ALC-ON, SCA-UP (increase=2), FCA-DOWN (reduction=4), FCA-UP (increase=1). 
         [0030]    According to this protocol, the TC-Type command line does not make it possible to distinguish between the activation commands of ON and OFF type, or between the execution commands of UP and DOWN type of the various selected functions, which is why it is necessary to add to the electrical control interface two additional command inputs respectively dedicated to executing the function selected in the first direction ON/UP or in the second direction OFF/DOWN and thus making it possible to determine the direction in which the selected function must be executed. 
         [0031]    According to a second embodiment of the invention represented in  FIG. 5 , the electrical remote control interface of the same LDLA equipment as that of  FIG. 1  has only two command inputs, each command input being associated with an outbound pulsed command line and a return line, the return line possibly being common to two outbound lines. The first command line, called TC-Type, corresponds to the selection of a type of function, the directions ON and OFF and the directions UP and DOWN associated with each function being considered as different types of functions. The second command line, called EXE, corresponds to the launching of the execution of the selected type of function. 
         [0032]      FIG. 6  shows an exemplary sequencing of the command signals corresponding to the performance of several successive types of functions, according to the second embodiment of the invention. In this example, the selections of the RF ON and RF OFF functions correspond to command signals respectively comprising two consecutive pulses and three consecutive pulses, the selections of the ALC ON and ALC OFF functions correspond respectively to a signal with four consecutive pulses and to a signal with five consecutive pulses, and the selections of the functions FCA-UP, FCA-DOWN, SCA-UP, SCA-DOWN, GCA-UP, GCA-DOWN correspond to command signals respectively comprising six to eleven consecutive pulses. The ten types of command functions of the LDLA equipment are complemented with an eleventh function, corresponding to an INHIBIT command, dedicated to cancelling the last command emitted and not yet executed. 
         [0033]    The sequencing represented in  FIG. 6  is identical to that represented in  FIG. 4  and corresponds to the following functions: RF-OFF (once), RF-ON (once), GCA-DOWN (reduction=2), INHIBIT (cancellation of the current command), ALC-ON (once), SCA UP (increase=two), FCA-DOWN (reduction=4), FCA-UP (increase=1). 
         [0034]    The command signals for executing successive types of functions can, for example, comprise a single pulse. In this case, the performance of the same function several times in succession corresponds to the emission of several consecutive pulses over the same EXE command line. The delimiting of the commands applied to the TC-Type command line is then performed by the first pulse which arrives on the EXE line after the activation of the function on the TC-Type line. The countdown of the pulses emitted to the selection command input TC-Type is performed by countdown means, not represented, internal to the electrical remote control interface and is reset after the execution of each function. 
         [0035]    This second embodiment of the invention is therefore the embodiment that has the fewest command inputs but it is less flexible in use than the first embodiment of the invention because, in the case where the same function must be executed successively in a first direction and then in a second direction, the type of function to be executed must be indicated twice in succession on the TC-TYPE command input. 
         [0036]    Although the first two embodiments of the invention present a minimal number of command inputs, in some applications, it may be desirable to add additional command inputs. According to a third embodiment, the electrical remote control interface for the same LDLA equipment as that of  FIG. 1  comprises four command inputs. The first two command lines, respectively called TC-Type-plus and TC-Type-minus, applied to the first two command inputs consist of signals intended to select at least one type of function to be performed from the plurality of functions that are possible: RF, ALC, FCA, GCA, SCA, INHIBIT. The last two command lines EXE-ON-UP and EXE-DOWN-OFF, respectively applied to a third and a fourth command input, consist of signals for activating the selected function in a first direction ON or UP or in a second direction OFF or DOWN. According to this third embodiment of the invention, the countdown of the pulses emitted to the selection command inputs is not reset after the execution of each function but is continued with the incrementing or decrementing of the countdown depending on the following type of function to be executed. Each function applied to the first command line TC-Type-plus makes it possible to increment the countdown of the pulses and each pulse applied to the second command line TC-Type-minus makes it possible to decrement the countdown of the pulses. When the number of pulses counted corresponds to that of the function to be executed, one or more pulses are emitted to one of the command inputs dedicated to the execution of that function. 
         [0037]      FIG. 8  shows an exemplary sequencing of the command signals corresponding to the performance of several successive types of functions, according to the third embodiment of the invention. The sequencing of the different types of functions is identical to that represented in  FIGS. 4 and 6  and corresponds to the following functions: RF-OFF (once), RF-ON (once), GCA-DOWN (reduction=2), INHIBIT (cancellation of the current command), ALC-ON (once), SCA-UP (increase=two), FCA-DOWN (reduction=4), FCA-UP (increase=1). The operation of the execution lines for the two command inputs EXE-ON-UP and EXE-DOWN-OFF and the number of pulses allocated to each type of function are identical to those described in conjunction with  FIG. 4 , except for the INHIBIT function. In the exemplary embodiment of  FIG. 8 , the number of pulses of the INHIBIT function is variable and depends on the number of pulses entered in error on one of the command inputs TC-Type-plus or TC-Type-minus and that are to be removed or added by the countdown means. Alternatively, the INHIBIT function can be performed in the same way as in the embodiments of  FIGS. 4 and 6 , by assigning this function a number of pulses greater than that assigned to all the other functions. Another difference lies in the selection of the different types of function that is performed through the intermediary of two command lines instead of just one. Thus, to perform the first two functions RF-OFF, RF-ON, a pulse is applied to the first selection command line TC-Type-plus to increment the number of pulses counted down to the value  1  then a pulse is emitted to the execution command input EXE-DOWN-OFF followed by a pulse to the execution command input EXE-UP-ON. The performance of the next function GCA-DOWN=2 is handled by the application of four successive pulses to the first selection command line TC-Type-plus to increment the countdown of the pulses from the value  1  to the value  5 , then a pulse is emitted twice in succession to the execution command input EXE-DOWN-OFF to perform the GCA-DOWN function twice. The two pulses then emitted over the second selection command line TC-Type-minus that have decremented the countdown of the pulses from the value  5  to the value  3  are neutralized by two pulses that are then emitted over the first selection command line TC-Type-plus, which corresponds to an INHIBIT function. No execution pulse is therefore needed to perform the INHIBIT function according to this exemplary embodiment. Since the number of pulses counted down again has the value  5 , it must be decremented by three units to drop to the value  2  and perform the following function ALC-ON, then incremented by two units to reach the value  4  and perform the function SCA-UP=2, and finally be decremented once again to reach the value  3  and perform the functions FCA-DOWN=4 and FCA-UP=1. 
         [0038]    Although the invention has been described in conjunction with particular embodiments and for a particular equipment item, it is obvious that it is by no means limited and that it includes all the technical equivalents of the means described and their combinations, provided that the latter fall within the scope of the invention.