This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2008-067767, filed on Mar. 17, 2008; the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a receiving apparatus, a transmission/reception system and a device control method receiving a radio signal for controlling a device.
2. Description of the Related Art
When controlling a plurality of devices with signals from one remote controller (hereinafter, refer to as “remocon”), there is a possibility of generating errors in control due to an arrangement of devices or the like. For instance, if devices A and B are arranged on a straight line seen from the remote controller, the device B may receive a signal for controlling the device A, resulting that it may falsely operate. Note that there is disclosed a technique in which a position of remocon is detected and a device to be an object to be controlled is specified based on the position and a position of the device, to thereby control the device using signals including an ID of the device (refer to JP-A 2004-166193 (KOKAI)).
In the above-described technique, it is required to set positional information on devices and to detect the position of the remocon. For this reason, it becomes necessary to reset the positional information on devices each time the devices are moved or a room is redecorated.
An object of the present invention is to provide a receiving apparatus, a transmission/reception system and a device control method having an improved reliability of controlling devices.
A receiving apparatus according to one aspect of the present invention includes: a receiving unit receiving a set of a plurality of signals in which at least a part of transfer rates is different; a rate detecting unit detecting a plurality of transfer rates of the plurality of signals; a first obtaining unit obtaining first information based on the plurality of transfer rates; a second obtaining unit obtaining second information based on the plurality of signals; and a control signal generating unit generating a control signal controlling a device based on the first and second information.
A transmission/reception system according to one aspect of the present invention includes the aforementioned receiving apparatus and a transmitting apparatus transmitting the above-described set of signals.
A device control method according to one aspect of the present invention includes: receiving a set of a plurality of signals in which at least a part of transfer rates is different; detecting a plurality of transfer rates of the plurality of signals; obtaining first information based on the plurality of transfer rates; obtaining second information based on the plurality of signals; and generating a control signal controlling a device based on the first and second information.
a) and 5(b) are timing charts representing signals at a rate detecting unit 133.
Concepts of embodiments herein below will be explained. In the embodiments hereinbelow, a device is controlled by transferring a set of a plurality of signals in which at least a part of transfer rates is different. Specifically, control information is transferred by varying the transfer rate (baud rate). For instance, the control information is handled as information which transfers values of transfer rates or a difference in the values. As a result of this, it becomes possible to control the device using two main and sub transfer channels. The information through the main transfer channel is represented by a signal itself (for instance, an amplitude of signal (H/L)). The information through the sub transfer channel is represented by a transfer rate (or a difference in transfer rates). Through each of the main channel and the sub channel, a command controlling the device and an ID (Identification) of the device, for instance, can be transferred in parallel. As such, by transferring the control information using the two transfer channels, reliability and confidentiality when controlling the device can be improved.
Hereinafter, embodiments of the present invention will be explained in detail.
The transmitting apparatus 110 is, for example, a portable transmission terminal, and functions as a so-called remocon which controls a device. The transmitting apparatus 110 includes a signal generating unit 111, a modulation unit 112, a control unit 113 and an antenna 114, and transmits a set of a plurality of signals in which at least a part of transfer rates is different, as shown in
The receiving apparatus 130 receives the signal to generate a command and a trigger signal, and outputs them to the device. The command is a signal for controlling the device. The trigger signal is a signal for shifting a state of the device (shift from a dormant state to an active state (power supply ON), for instance). The receiving apparatus 130 includes an antenna 131, a rectifying unit 132, a rate detecting unit 133, a decoding unit 134, an ID calculating unit 135, an ID verifying unit 136, a mode detecting unit 137, an ID setting unit 138 and an output unit 139.
The antenna 131 receives the signal transmitted from the transmitting apparatus 110.
The rectifying unit 132 includes a power generating part in which power is generated by the signal received by the antenna 131, and a demodulation part obtaining a demodulated signal from the signal. By the electric power supplied from the rectifying unit 132, the rate detecting unit 133, the decoding unit 134, the ID calculating unit 135, the ID verifying unit 136, the mode detecting unit 137 and the ID setting unit 138 are driven. For this reason, the receiving apparatus 130 can be operated in low power consumption.
When the RF signal is input, a half-wave current is flown through a path of the transistor MR1, the capacitor C2 and the transistor MR2. As a result of this, direct current output voltages (rectified voltages) are generated at both ends of the capacitor C2. A lower terminal DC− of the rectifying unit 132 shown in
The rate detecting unit 133 detects a transfer rate (concretely, a baud rate) of the demodulated signal output from the rectifying unit 132. Next, a detection method of the transfer rate will be described. Hereinafter, two detection methods will be described, and either of the detection methods can be applied. Further, there is no problem if other methods are applied to the detection of the transfer rate.
(1) A first rate detection method will be explained. The demodulated signal output from the rectifying unit 132 is represented in
Here, when a signal format is set so that the demodulated signal includes a fixed pattern (specific bit string) (when there is a preamble for estimating the baud rate), it is possible to estimate the transfer rate (baud rate) by one time of the measurement.
Hereinafter, details regarding the above will be described. Here, the rate detecting unit 133 is supposed to have an oscillating part (not shown) which generates clock signals. Further, an oscillation frequency of this oscillating part (not shown) is supposed to be larger than the baud rate to be detected. This is because the time interval T is measured by the clock signals.
a) and 5(b) are timing charts representing signals at the rate detecting unit 133.
When the rate detecting unit 133 detects the next bit B2, the counting of clock signals in the oscillating part is started again, and the counting is continued until a rising edge of the next bit B3 is detected. Here, a count number n2 is 5.
The rate detecting unit 133 compares the count number n1 with the count number n2, and it determines, when the n1 is not less than (n2−a) nor more than (n2+a), the transfer rate is detected (a: error). Here, n1=5 and n2=5, so that the rate detecting unit 133 determines that the transfer rate is detected, and calculates a transfer rate R using, for instance, the following formulas.
R=1/(n0*T)
n0=(n1+n2)/2
n0: count number of clock signals per one symbol (one bit, in this example)
τ: time per one clock
The rate detecting unit 133 detects the transfer rate each time it receives the signal. As a result of this, the transfer rates R1, R2 and R3 are detected in this order, for example.
(2) A second rate detection method will be described. Here, the transfer rate is estimated from a power spectrum of the demodulated signal output from the rectifying unit 132 or of the received signal output from the antenna 131.
The baud rate can be estimated without searching the minimum level of the main lobe S0. It is possible to estimate the baud rate from a frequency width Δf1 at a point where the frequency is lowered by a predetermined value (X[dB]) from the maximum level of the main lobe S0 of the power spectrum. A shape of the power spectrum is determined by a signal to be transmitted. Specifically, there is a relation of Δf0=α*Δf1 between the frequency width Δf1 and the frequency interval Δf0. If a coefficient α is determined, the baud rate can be estimated by calculating the frequency interval Δf0 from the frequency width Δf1. The coefficient α can be stored in the rate detecting unit 133 as a lookup table or the like.
The decoding unit 134 performs a decoding processing on the demodulated signal based on rate information obtained in the rate detecting unit 133, to thereby obtain a decoded signal (decoded information and data portion). Concretely, data regarding High/Low (1/0) of the demodulated signal is collected at a timing corresponding to the transfer rate R detected by the rate detecting unit 133. The decoded signal can be used as a control command and control data of a rear stage device. The decoding unit 134 functions as a second obtaining unit obtaining second information based on the plurality of signals.
Hereinafter, a concrete example of an operation of the decoding unit 134 will be shown based on
Note that the operational contents of the decoding unit 134 may be appropriately changed depending on a form of the signal to be transferred.
The ID calculating unit 135 obtains ID information from the transfer rate R detected in the rate detecting unit 133 (obtainment of rate portion). The ID calculating unit 135 functions as a first obtaining unit obtaining first information based on the plurality of transfer rates. Here, a concrete obtaining method of the ID information when the transfer rates R1, R2 and R3 are obtained will be explained. Note that in the following calculations, only integral parts are used and fractions below decimal point are rounded down.
(1) In the first method, a difference in the transfer rates is regarded as information. For example, when a reference rate and a rate resolution are respectively set as R1 and ΔR, an amount of information to be transferred is represented by log2|R2−R1|/ΔR[bit] and log2|R3−R1|/ΔR[bit]. At this time, numeric values A1=|R2−R1|/ΔR and Δ2=|R3−R1|/ΔR themselves can be regarded as transfer information. Further, it is also possible to convert these numeric values A1 and A2 into the transfer information by referring to the lookup table.
These numeric values A1 and A2 can be respectively handled as ID information. In this case, the numeric values A1 and A2 may be the same value and may indicate the same ID information. Further, the numeric values A1 and A2 may be different values and may indicate different pieces of ID information. Furthermore, the numeric values A1 and A2 can be combined together and handled as one ID information. Here, a case is assumed where the ID information is obtained as information in which the numeric values A1 and A2 are combined together. For example, the numeric values A1 and A2 are disposed in this order on a high-order bit side and a low-order bit side. Alternatively, an opposite pattern thereof can also be conceivable. The ID information is obtained as described above.
(2) In the second method, the transfer rates themselves are regarded as information. An amount of information to be transferred is represented by log2(R1/ΔR) [bit], log2(R2/ΔR) [bit], and log2(R3/ΔR)[bit]. At this time, numeric values B1=R1/ΔR, B2=R2/ΔR, and B3=R3/ΔR themselves can be regarded as transfer information. Alternatively, it is also possible to convert these numeric values B1 through B3 into the transfer information by referring to the lookup table. The numeric values B1 through B3 can be handled independently or by combining them together.
The ID verifying unit 136 compares the ID information obtained in the ID calculating unit 135 with an original ID previously stored in the ID setting unit 138 and outputs its result to the output unit 139. If these IDs coincide with each other, a command corresponding to the decoded signal is output from the output unit 139 to the rear stage device. If the IDs do not coincide with each other, the output of the command from the output unit 139 to the device is not conducted.
The mode detecting unit 137 compares the ID information calculated in the ID calculating unit 135 with the decoded information decoded in the decoding unit 134. When the ID information and the decoded information coincide with each other, the ID information and information indicating coincidence are output to the ID setting unit 138. Here, the coincidence between the ID information and the decoded information is supposed to indicate a shift into an ID changing mode in which an ID can be changed. In the ID changing mode, IDs held in the ID setting unit 138 can be changed.
The ID setting unit 138 holds one or a plurality of ID(s). When the ID setting unit 138 holds the plurality of IDs, it holds information indicating which ID among the plurality of IDs is the original ID. In preparation for changing the ID of device, the ID setting unit 138 holds the plurality of IDs. Among them, an ID used for controlling the device is the original ID. In the ID changing mode, the ID setting unit 138 changes the original ID. Specifically, the ID setting unit 138 functions as a changing unit changing an identification of device.
When the ID verifying unit 136 determines that the IDs coincide with each other, the output unit 139 outputs the command corresponding to the decoded signal. For example, the ID verifying unit 136 outputs a trigger signal for turning on the power supply to the device. As a result of this, a state of device changes from a dormant state to an active state, and electric power is supplied to the entire of the device. The output unit 139 functions as a control signal generating unit generating a control signal controlling the device based on the first and second information.
Hereinafter, an operation of the control system 100 will be described.
The control signal for controlling device is transmitted from the transmitting apparatus 110 and is received by the receiving apparatus 130 (step S11). A rate portion (ID information) and a data portion (decoded information) of the control signal respectively represent the original ID and a control command (control data) of the device.
Here, when the control signal is represented by a set of signals of the transfer rates R1, R2 and R3, for instance, the same command can be corresponded to each data portion of the signals of the transfer rates R1, R2 and R3. In this case, it is possible to reduce a malfunction of device due to an error in transfer, by using a majority decision.
Note that when both the rate portion and the data portion of the signal represent the original ID, the signal corresponds to a later-described mode changing signal.
The control signal is demodulated in the rectifying unit 132, to thereby generate the demodulated signal. A data portion (demodulated information) is obtained from the demodulated signal by the decoding unit 134 (step S12). Meanwhile, a rate portion (ID information) is obtained from the demodulated signal by the rate detecting unit 133 and the ID calculating unit 135 (step S13). Note that these steps S12 and S13 are simultaneously executed in parallel.
It is determined whether or not the rate portion (ID calculated by the ID calculating unit 135 (ID transmitted by radio wave)) coincides with the ID held in the ID setting unit 138 (step S14). If these IDs coincide with each other, a command is output to the device. For example, the device in a dormant state is activated (power supply ON) (step S15). If these IDs do not coincide with each other, the control command (control data) is discarded as invalid, and the device is not controlled.
As described above, when the same command is corresponded to each data portion of the signals of the transfer rates R1, R2 and R3, for instance, the majority decision can be applied. Specifically, when the commands represented by these data portions do not completely coincide with each other, the command at the majority side is output to the device. As a result of this, the malfunction of device due to an error in transfer can be reduced.
A case is assumed where the ID of device is changed. By changing the ID of device held in the receiving apparatus 130, it is possible to enhance a security and to eliminate a chance of overlap of IDs. Here, the ID of device is changed using the mode changing signal and an ID notifying signal.
The mode changing signal for setting the receiving apparatus 130 to the ID changing mode is transmitted from the transmitting apparatus 110 and is received by the receiving apparatus 130 (step S21). Here, in the mode changing signal, both a rate portion (ID information) and a data portion (decoded information) are supposed to represent the original ID. The data portion (decoded information) and the rate portion (ID information) are obtained by the decoding unit 134 and the ID calculating unit 135, respectively (steps S22 and S23).
It is determined whether or not the both rate portion (ID information) and the data portion (decoded information) coincide with the ID held in the ID setting unit 138 (step S24). Specifically, if the three IDs coincide with one another, the receiving apparatus 130 is set to the ID changing mode (step S25).
The above point will be more specifically described. The mode detecting unit 137 checks whether or not the rate portion (ID information) coincides with the data portion (decoded information), and outputs its result (first result information) to the ID setting unit 138. Meanwhile, the ID verifying unit 136 compares the rate portion (ID information) obtained in the ID calculating unit 135 with the original ID previously stored in the ID setting unit 138, and outputs its result (second result information) to the ID setting unit 138. If both the first and second result information indicate coincidence, information indicating the ID changing mode is held in the ID setting unit 138.
In the above description, both the rate portion (ID information) and the data portion (decoded information) of the mode changing signal coincide with the original ID. Instead of this, it is also possible to set a signal in which a command representing a mode change is indicated in a data portion (decoded information) as the mode changing signal. In this case, only the rate portion (ID information) coincides with the original ID. Since a processing at this time is not fundamentally different from one in a case where both the rate portion (ID information) and the data portion (decoded information) coincide with the original ID, a detailed explanation thereof will be omitted.
The ID notifying signal for notifying the receiving apparatus 130 of the changed ID is transmitted from the transmitting apparatus 110 and is received by the receiving apparatus 130 (step S31). Here, in the ID notifying signal, both a rate portion (ID information) and a data portion (decoded information) are supposed to represent the changed ID. The data portion (decoded information) and the rate portion (ID information) are obtained by the decoding unit 134 and the ID calculating unit 135, respectively (steps S32 and S33).
It is determined whether or not both the rate portion (ID information) and the data portion (decoded information) coincide with the ID held in the ID setting unit 138 (step S34). As a result of this, if the three IDs coincide with one another, and the receiving apparatus 130 is in the ID changing mode (step S35), the original ID held in the ID setting unit 138 is changed (step S36).
In the above description, both the rate portion (ID information) and the data portion (decoded information) of the ID notifying signal coincide with the changed ID. Instead of this, it is also possible to set a signal in which a command representing an ID notification is indicated in a data portion (decoded information) as the ID notifying signal. In this case, only the rate portion (ID information) coincides with the original ID. Since a processing at this time is not fundamentally different from one in a case where both the rate portion (ID information) and the data portion (decoded information) coincide with the changed ID, a detailed explanation thereof will be omitted.
According to the present embodiment, it is possible to obtain two independent transfer channels by transferring a set of a plurality of signals in which at least a part of transfer rates is different. By using these two transfer channels, reliability and confidentiality when controlling a device can be improved.
The ID of device can be changed by a signal from a side of remocon (side of transmitting apparatus 110). As a result of this, the malfunction of device can be reduced. Specifically, it is possible to reduce the malfunction of device due to an overlap of IDs or the like. Note that by using two transfer channels, the ID of device can be changed with a short code length.
By making the transfer rates of signal variable, it becomes easy to identify each signal, which enables to reduce the malfunction of device. Further, when the same information is corresponded to each data portion of a plurality of signals, it is possible to improve an error rate with the use of majority decision. It should be noted that different pieces of information can be corresponded to each data portion of the plurality of signals.
The ID of device can be changed by a signal from a side of remocon (side of transmitting apparatus 110). As a result of this, it becomes easy to secure confidentiality of the ID of device against a threat from the outside.
A second embodiment of the present invention will be described.
The ID verifying unit 236 compares ID information obtained in the ID calculating unit 135 with an original ID previously stored in the ID setting unit 138. If these IDs coincide with each other, the ID verifying unit 236 generates a timer activation signal and outputs it to the timer unit 240.
Upon receiving the timer activation signal from the ID verifying unit 236, the timer unit 240 starts counting time, and when the time is beyond the predetermined time, it outputs a warning signal. The timer unit 240 functions as a measuring unit measuring a time interval during which second and third signals are received.
The judgment unit 239 judges a presence/absence of the warning signal from the timer unit 240, and when no warning signal exists, it outputs a command to a following stage device.
The ID of device is changed (step S41). For example, it is possible to change the ID of device by following a procedure shown in
The device is controlled by the control signal. Basically, the device is controlled by a procedure similar to that shown in
Embodiments of the present invention are not limited to the aforementioned embodiments and can be expanded and modified, and the expanded and modified embodiments are also included in the technical scope of the present invention. Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2008-067767 | Mar 2008 | JP | national |