JP2017118259A - Slave unit, master unit, monitor, and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain synchronization even when deviation occurs in a duty factor of a reception waveform.SOLUTION: A first unique pattern detection part 151 samples preamble data included in reception data, and determines that the unique pattern is detected when the number of clocks between adjacent falling edges match to a specific number. A second unique pattern detection part 152 samples the preamble data included in the reception data at the same timing with the first unique pattern detection part 151, and determines that the unique pattern is detected when the number of clocks between adjacent rising edges match to the specific number. An enable signal formation part 153 outputs a trigger signal to a second clock formation part 114 when inputting a signal indicating that the unique pattern is detected from the first unique pattern detection part 151 or the second unique pattern detection part 152, and outputs an enable signal to a data reproduction part 133.SELECTED DRAWING: Figure 9

Description

  The present disclosure relates to a child device, a parent device, a monitor of a door phone system, and a communication method of the door phone system.

  In recent years, in homes and the like, for example, a slave unit with a camera (hereinafter referred to as an “entrance slave unit”) installed at a front door outside the home, and an image captured on the monitor of the entrance slave unit camera on a monitor A door phone system comprising a main phone (hereinafter referred to as “door phone master”) is widely used. In some cases, a monitor is added to the door phone system (hereinafter referred to as “additional monitor”).

  Generally, in a door phone system, an entrance cordless handset and a door phone master phone are connected by a two-wire cable. Further, the door phone master unit and the extension monitor are connected by a two-wire cable. Patent Document 1 describes a door phone system that transmits and receives packets between an entrance cordless handset and a doorphone master set connected by a two-wire cable.

  The entrance slave unit, door phone master unit, and extension monitor detect the synchronization timing (the timing at the beginning of each bit of the received data) with the communication partner using the preamble data included in the received signal.

JP 2007-124227 A

  When the length of the two-wire cable changes, the impedance of the cable changes, and the rising characteristics and falling characteristics of the received waveform change in the receiving side device. Further, it is conceivable that the duty ratio of the received waveform is deviated from the ideal value (50%) due to the distortion of the input / output characteristics of the bus driver of the receiving side device or the difference between the rising and falling receiving hysteresis of the receiving waveform. In the prior art, measures against out-of-synchronization due to the deviation of the duty ratio of the received waveform have not been studied.

  The objective of this indication is providing the communication method of the subunit | mobile_unit of a door phone system, a main | base station, a monitor, and a door phone system which can maintain a synchronization, even if the duty ratio of a received waveform has generate | occur | produced.

  A child device of the present disclosure is a child device of a door phone system that is connected to a parent device via a two-wire cable and transmits / receives a packet signal to / from the parent device by time-division duplex, and has a preamble at a predetermined position. A receiver that receives data in which a sync pattern is arranged, a first clock generator that outputs a clock of a first frequency corresponding to n times (n is 1 or more) the bit rate of the received data, A second clock generation unit configured to output a second frequency clock corresponding to a bit rate of the received data, which is generated based on a clock of one frequency, and the received data is sampled using the first frequency clock; First unique pattern detection that establishes bit synchronization by detecting a unique pattern in the preamble based on the number of clocks between adjacent falling edges. And sampling the received data using a clock of the first frequency and detecting a unique pattern in the preamble based on the number of clocks between adjacent rising edges to establish bit synchronization A unique pattern detection unit and a data reproduction unit that reproduces the received data using a clock of the second frequency after bit synchronization is established by the first unique pattern detection unit or the second unique pattern detection unit. And.

  A parent device of the present disclosure is a parent device of a door phone system that is connected to a child device via a two-wire cable and transmits / receives packet signals to / from the child device by time-division duplex, and has a preamble at a predetermined position. A receiver that receives data in which a sync pattern is arranged, a first clock generator that outputs a clock of a first frequency corresponding to n times (n is 1 or more) the bit rate of the received data, A second clock generation unit configured to output a second frequency clock corresponding to a bit rate of the received data, which is generated based on a clock of one frequency, and the received data is sampled using the first frequency clock; First unique pattern detection that establishes bit synchronization by detecting a unique pattern in the preamble based on the number of clocks between adjacent falling edges. And sampling the received data using a clock of the first frequency and detecting a unique pattern in the preamble based on the number of clocks between adjacent rising edges to establish bit synchronization A unique pattern detection unit and a data reproduction unit that reproduces the received data using a clock of the second frequency after bit synchronization is established by the first unique pattern detection unit or the second unique pattern detection unit. And.

  The monitor according to the present disclosure is added to a door phone system including a parent device and a child device, is connected to the parent device via a two-wire cable, and transmits and receives packet signals to and from the parent device by time division duplex. A monitor of a door phone system, wherein the reception unit receives data in which a preamble and a sync pattern are arranged at predetermined positions, and a first frequency corresponding to n times (n is 1 or more) of the bit rate of the received data. A first clock generation unit that outputs a clock; a second clock generation unit that generates a clock of a second frequency corresponding to the bit rate of the received data, which is generated based on the clock of the first frequency; and the first The received data is sampled using a frequency clock, and the unique pattern in the preamble is sampled based on the number of clocks between adjacent falling edges. A first unique pattern detecting unit that establishes bit synchronization by sampling and sampling the received data using a clock of the first frequency, and in the preamble based on the number of clocks between adjacent rising edges A second unique pattern detection unit for detecting a unique pattern to establish bit synchronization; and after the bit synchronization is established by the first unique pattern detection unit or the second unique pattern detection unit, the second unique pattern detection unit And a data reproducing unit that reproduces the received data using a frequency clock.

  The communication method of the present disclosure is a communication method of a door phone system in which a parent device and a child device are connected via a two-wire cable, and packet signals are transmitted and received between the parent device and the child device by time division duplex. The transmitting side apparatus transmits data in which a preamble is arranged at a predetermined position, the receiving side apparatus receives data transmitted from the transmitting side apparatus, and is n times the bit rate of the received data ( the received data is sampled using a clock of a first frequency corresponding to n is 1 or more), and in the preamble based on the number of clocks between adjacent falling edges or the number of clocks between adjacent rising edges Bit of the received data generated with reference to the clock of the first frequency after the bit synchronization is established. Playing the received data using a clock of the second frequency corresponding to the over and.

  According to the present disclosure, synchronization is maintained even when there is a deviation in the duty ratio of a received waveform by detecting a unique pattern in which the number of sampling clocks between adjacent falling edges or between adjacent rising edges is unique. be able to.

The system block diagram which shows the structure of the door phone system which concerns on one embodiment of this indication The figure which shows the frame structure and slot structure which concern on one embodiment of this indication The figure which shows the structure of the interrupt signal which concerns on one embodiment of this indication The block diagram which shows the structure of the entrance cordless handset which concerns on one embodiment of this indication The block diagram which shows the structure of the door phone main unit which concerns on one embodiment of this indication The block diagram which shows the structure of the expansion monitor which concerns on one embodiment of this indication The figure which shows an example of the modulation process with respect to packet data (1 bit) The figure which shows an example of the modulation process with respect to packet data (multiple bits) The figure which shows an example of the preamble data used in one embodiment of this indication The block diagram which shows the internal structure of the synchronous detection part of the entrance cordless handset which concerns on one embodiment of this indication The figure which shows an example of the synchronous detection process of the entrance cordless handset which concerns on one embodiment of this indication The figure explaining the detection of the unique pattern of the entrance cordless handset which concerns on one embodiment of this indication The figure which shows the decoding timing of the entrance cordless handset which concerns on one embodiment of this indication The flowchart which shows an example of operation | movement of the synchronous detection process which concerns on one embodiment of this indication Sequence diagram until initial registration according to an embodiment of the present disclosure Sequence diagram from standby state to communication state according to an embodiment of the present disclosure The flowchart which shows an example of operation of the entrance cordless handset concerning an embodiment of this indication The flowchart which shows an example of operation of the door phone main unit concerning an embodiment of this indication The figure which shows the specific example of the routing control at the time of normal operation | movement of the door phone main unit which concerns on one embodiment of this indication The figure which shows the internal structure of the routing control part of the door phone main unit which concerns on one embodiment of this indication The figure which shows the specific example of the routing control at the time of the initial registration of the door phone main unit which concerns on one embodiment of this indication The block diagram which shows the variation of the internal structure of the synchronous detection part of the entrance cordless handset which concerns on one embodiment of this indication The flowchart which shows an example of the operation | movement of the variation of the synchronous detection process which concerns on one embodiment of this indication

  Even if the length of the two-wire cable is changed and the duty ratio is shifted, the inventor of the present application has the same falling characteristics of the received waveform on the receiving side, and the rising characteristics are all the same. Since the reception characteristics of the same are the same for the falling and rising edges, the time between the adjacent rising edges of the received waveform or the time between the adjacent falling edges is hardly changed from that of the transmission waveform. And this led to the present invention.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

<System overview>
First, the outline | summary of the door phone system which concerns on one embodiment of this indication is demonstrated using FIG. As shown in FIG. 1, the door phone system 1 includes an entrance cordless handset 100 and a door phone master set 200. Note that FIG. 1 illustrates a case where three door slave devices 100-1, 100-2, and 100-3 are connected to the doorphone master device 200. Further, an additional monitor 300 may be added to the door phone system 1. Furthermore, the door phone system 1 can be connected to other door phone systems.

  The entrance cordless handset 100 is provided, for example, at the entrance of a house or the like. The intercom master device 200 and the extension monitor 300 are provided in a home such as a house, for example, and are fixed to a wall or placed on a table or a table. The entrance cordless handset 100 and the door phone master set 200 are connected by a two-wire cable made of a pair of copper wires. The extension monitor 300 is connected to the door phone master unit 200 by a two-wire cable.

  The intercom master device 200 communicates with the entrance slave device 100, receives video data, audio data, and control data from the entrance slave device 100, and transmits the audio data and control data. The intercom base unit 200 communicates with the expansion monitor 300, transfers the video data, audio data, and control data received from the front door unit 100 to the expansion monitor 300, and receives the audio data and control data received from the expansion monitor 300. Is transferred to the entrance cordless handset 100.

  In the following description, the direction from the entrance slave unit 100 or the extension monitor 300 to the doorphone master unit 200 is referred to as “upward direction”, and packets and signals transmitted from the entrance slave unit 100 or the extension monitor 300 in the upward direction are referred to as “upward direction”. They are called “upstream packet” and “upstream signal”, respectively. Further, the direction from the doorphone master unit 200 to the entrance slave unit 100 or the extension monitor 300 is referred to as “downward direction”, and packets and signals transmitted from the doorphone master unit 200 in the downward direction are referred to as “downstream packet” and “downstream signal”, respectively. "

<Frame configuration, slot configuration>
Next, a frame configuration and a slot configuration during synchronous communication according to the present embodiment will be described with reference to FIG. 2A. As shown in FIG. 2A, each frame has a 48000 bit area, has a 10 ms period, a 4.8 Mbps bit rate, and is divided into 24 slots. Therefore, each slot has an area of 2000 bits = 250 bytes, and has a bit rate of 0.416 ms and a bit rate of 4.8 Mbps.

  Each slot is divided into a 52-byte guard space (Guard), a 4-byte preamble field, a 2-byte sync field (Sync), a 32-byte control data field, and a 160-byte user data field.

  The guard space is a time for avoiding a slot collision due to a propagation delay time difference, clock jitter, or the like. Preamble data (described later) having a predetermined unique pattern is added to the preamble field. A predetermined sync pattern is added to the sync field. Control data is added to the control data field. Image data and audio data are added to the user data field. Here, the sync pattern is known data or a data string arranged in the sync field, and is used to establish synchronization at the time of reception data reception, and confirms that reception data has been received at an accurate timing. This is a known data pattern defined in advance.

<Configuration of interrupt signal>
Next, the configuration of an interrupt signal during asynchronous communication according to the present embodiment will be described with reference to FIG. 2B.

  As shown in FIG. 2B, the interrupt signal is divided into a 4-byte preamble field, a 2-byte sync field (Sync), and a 32-byte control data field. Further, the interrupt signal shown in FIG. 2B is provided with a 30-byte user data field for future expansion.

  The preamble data and the sync pattern of the interrupt signal are the same as the slots in the synchronous communication shown in FIG. 2A. Thereby, since a receiving part etc. can be shared by the time of synchronous communication and the time of asynchronous communication, cost can be held down.

  In the control data field of the interrupt signal, control information such as a message type (synchronization request or the like) and a transmission source device number (ID) is written. The user data field of the interrupt signal may be used as a field for notifying detailed information corresponding to the message type, such as device abnormality information (information indicating that a device abnormality is detected).

  Note that the interrupt signal shown in FIG. 2B is also used during initial registration of the connected device.

<Configuration of entrance cordless handset>
Next, the structure of the entrance cordless handset 100 is demonstrated using the block diagram of FIG. As shown in FIG. 3, the entrance slave device 100 includes a cable connection unit 101, a key input unit 102, a speaker 103, a microphone 104, an audio I / F (interface) unit 105, a camera unit 106, and a control unit 107. The control unit 107 includes a first clock generation unit 131, a packet generation unit 132, a data reproduction unit 133, and a connection state detection unit 134 inside. Further, the entrance slave device 100 includes a transmission data processing unit 108, a transmission data inversion unit 109, a transmission driver 110, a reception driver 111, a reception data inversion unit 112, a synchronization detection unit 113, a second clock generation unit 114, and an identifier storage unit 115. Have

  The cable connection unit 101 includes a connection terminal for a two-wire cable, and connects the one end on the entrance side of the two-wire cable to the reception driver 111 and the transmission driver 110 in a state where signals can be transmitted. Note that the other end of the two-wire cable is connected to the doorphone master unit 200.

  The key input unit 102 includes a call button. When the call button is operated, the key input unit 102 outputs a signal indicating that to the control unit 107.

  The speaker 103 converts the analog audio data output from the audio I / F unit 105 into audio and outputs the audio.

  The microphone 104 collects ambient sound, converts it into analog sound data, and outputs it to the sound I / F unit 105.

  The audio I / F unit 105 converts the digital audio data output from the control unit 107 into analog audio data, adjusts the signal level, and outputs the analog audio data to the speaker 103. The audio I / F unit 105 adjusts the signal level of the analog audio data output from the microphone 104, converts the analog audio data into digital audio data, and outputs the digital audio data to the control unit 107. Such analog / digital conversion is performed by an A / D, D / A converter (not shown).

  The audio I / F unit 105 outputs data obtained by performing predetermined audio compression processing on the data obtained by digitally converting the analog audio data output from the microphone 104 to the control unit 107 as digital audio data. May be. In addition, when the digital audio data output from the control unit 107 is data obtained by performing predetermined audio compression processing, the audio I / F unit 105 performs predetermined audio expansion processing on the data. To digital / analog conversion.

  The camera unit 106 includes a digital camera, takes a video of the entrance, generates digital video data, and outputs the digital video data to the control unit 107. Note that the camera unit 106 may include an encoder module. That is, the camera unit 106 may output data obtained by performing predetermined moving image compression processing such as H.264 to the video data output from the digital camera to the control unit 107 as digital video data.

  The control unit 107 controls each part of the entrance cordless handset 100. In addition, the control unit 107 outputs a transmission control signal (SW CON) that indicates a transmission period that permits transmission and a reception period that permits reception to the transmission driver 110 and the reception driver 111.

  The first clock generation unit 131 of the control unit 107 is a clock for sampling the reception data, and the first frequency corresponding to n times (n is 1 or more) the bit rate of the reception data on the basis of the crystal oscillation. A clock (CLK) of (eg, 48 MHz (n = 10)) is generated and output to the synchronization detection unit 113 and the second clock generation unit 114.

The packet generation unit 132 of the control unit 107 generates an uplink packet for realizing a call with video. Specifically, the packet generation unit 132 divides the digital audio data output from the audio I / F unit 105 and the digital video data output from the camera unit 106 as appropriate and writes them to the user data field of each slot. Control data including an identifier (hereinafter referred to as “own device ID _slave ”) unique to the device (the entrance _slave device 100) and an identifier of the communication partner doorphone parent device 200 (hereinafter referred to as “ID _master ”) is controlled in each slot. Write to the data field. Furthermore, the packet generation unit 132 writes preamble data and a sync pattern in each slot, and generates an uplink packet (transmission data). Further, the packet generation unit 132 generates a transmission enable signal (SSCS) and a transmission second frequency (for example, 4.8 MHz) clock (SSCK). Then, the packet generation unit 132 outputs the uplink packet to the transmission data processing unit 108 in synchronization with the transmission enable signal (SSCS) and the clock (SSCK).

  Note that, in a standby state in which data is not transmitted and received between the front door device 100 and the door phone master device 200, the packet generation unit 132 does not generate an upstream packet. In a standby state (during asynchronous communication), when a predetermined event such as an operation of a call button occurs, the packet generation unit 132 transmits an upstream packet (interrupt signal) in which preamble data, sync pattern, and control data are written. Generate. The preamble and sync pattern used in the interrupt signal during asynchronous communication are the same as those used during synchronous communication.

When the data reproduction unit 133 of the control unit 107 receives the enable signal (SSCS) from the synchronization detection unit 113, the data reproduction unit 133 uses the second frequency clock (SSCK) output from the second clock generation unit 114, and receives the data inversion unit. The downlink signal output from 112 is demodulated to obtain a downlink packet. Then, the data reproduction unit 133 outputs the digital audio data included in the downlink packet to the audio I / F unit 105, and outputs the sync pattern included in the downlink packet (received data) to the connection state detection unit 134. Note that the data reproduction unit 133 causes the identifier storage unit 115 to store its own device ID _slave and ID _master included in the downlink packet at the time of initial registration.

  Further, when a predetermined event occurs in a standby state (during asynchronous communication) and a downlink signal (interrupt signal) is input, the data reproduction unit 133 demodulates the downlink signal to acquire a downlink packet, and is included in the downlink packet The sync pattern is output to the connection state detection unit 134. The data reproduction unit 133 extracts control data of the interrupt signal after confirming that the connection state detection unit 134 has correctly captured the interrupt signal. If the control data is a synchronization request, the entrance slave device 100 shifts to a synchronization process with the doorphone master device 200.

  The connection state detection unit 134 of the control unit 107 is a check sync pattern (hereinafter, referred to as a “positive connection check sync pattern” (for example, all 16 bits are “0”)) when the two-wire cable is connected correctly. This is a reverse pattern of the normal connection check sync pattern, and the check sync pattern when the two-wire cable is reverse connected (hereinafter referred to as “reverse connection check sync pattern” (eg, all 16 bits are “1”). )) Is remembered. Then, the connection state detection unit 134 collates the sync pattern of the reception data output from the data reproduction unit 133 with the sync pattern for the normal connection check and the sync pattern for the reverse connection check. The connection state detection unit 134 determines that the two-wire cable is correctly connected when the sync pattern of the received data completely matches the sync pattern for the normal connection check, and the sync pattern of the received data and the sync pattern for the reverse connection check If the two completely match, it is determined that the two-wire cable is reversely connected. Then, the connection state detection unit 134 outputs an inversion control signal (INV CON) indicating the determination result to the transmission data inversion unit 109 and the reception data inversion unit 112.

  When the transmission data processing unit 108 receives the enable signal (SSCS) from the packet generation unit 132, the transmission data processing unit 108 uses the second frequency clock (SSCK) output from the packet generation unit 132, and the uplink data output from the packet generation unit 132. Modulation processing is performed on the packet data to generate an uplink signal, which is output to the transmission data inverting unit 109. Details (specific example) of the modulation processing of the transmission data processing unit 108 will be described later.

  When the connection state detection unit 134 determines that the two-wire cable is reversely connected, the transmission data inversion unit 109 inverts the uplink signal output from the transmission data processing unit 108 and outputs the inverted signal to the transmission driver 110. On the other hand, when the connection state detection unit 134 determines that the two-wire cable is a normal connection, the transmission data reversing unit 109 outputs the uplink signal output from the transmission data processing unit 108 to the transmission driver 110 as it is.

  The transmission driver 110 transmits an uplink signal to the intercom base unit 200 via the cable connection unit 101 in the transmission section instructed by the switching control signal (SW CON) from the control unit 107.

  The reception driver 111 receives the downlink signal transmitted from the doorphone master device 200 via the cable connection unit 101. Then, the reception driver 111 outputs a downlink signal to the reception data inversion unit 112 in the reception period instructed by the switching control signal (SW CON) from the control unit 107.

  When the connection state detection unit 134 determines that the two-wire cable is reversely connected, the reception data inversion unit 112 inverts the downlink signal output from the reception driver 111 to synchronize the detection unit 113 and the second clock generation unit. 114 and output to the data reproduction unit 133. On the other hand, when the connection state detection unit 134 determines that the two-wire cable is a positive connection, the reception data inversion unit 112 directly uses the downlink signal output from the reception driver 111 as the synchronization detection unit 113 and the second clock generation unit. 114 and output to the data reproduction unit 133.

  The synchronization detection unit 113 uses the first frequency clock (CLK) output from the first clock generation unit 131 and uses the preamble data included in the downlink signal output from the reception driver 111 to Synchronization (start timing of each bit of received data) is detected. Then, the synchronization detection unit 113 outputs a trigger signal serving as a reference for starting clock output to the second clock generation unit 114 at the timing when the unique pattern of the preamble data is detected, and an enable signal (SSCS) that permits the data reproduction operation Is output to the data reproducing unit 133. The details of the configuration of the synchronization detection unit 113 will be described later.

  The second clock generation unit 114 corresponds to the bit rate of the received data with reference to the first frequency clock (CLK) output from the first clock generation unit 131 at the timing instructed by the synchronization detection unit 113. A clock (SSCK) having two frequencies (for example, 4.8 MHz) is generated and output to the data reproducing unit 133.

The identifier storage unit 115 stores the own device ID _slave and the ID _master received from the intercom master device 200.

<Configuration of doorphone master unit>
Next, the configuration of door phone master device 200 will be described using the block diagram of FIG. As shown in FIG. 4, door phone master device 200 includes a cable connection unit 201, a key input unit 202, a speaker 203, a microphone 204, an audio I / F unit 205, a display unit 206, and a control unit 207. The control unit 207 includes a first clock generation unit 231, a packet generation unit 232, a data reproduction unit 233, a connection state detection unit 234, and an identifier setting unit 235 inside. The intercom 200 has a transmission data processing unit 208, a transmission data inversion unit 209, a transmission driver 210, a reception driver 211, a routing control unit 212, a synchronization detection unit 213, a second clock generation unit 214, and an identifier storage unit 215. Have. The doorphone parent device 200 has N (N is a natural number) the cable connection unit 201, the transmission driver 210, and the reception driver 211.

  The cable connection portion 201-i (i is any integer from 1 to N) includes a connection terminal for a two-wire cable, one end on the indoor side of the two-wire cable, a transmission driver 210-i, and a reception driver 211. -I is connected in a state where signals can be transmitted. In addition, the other end of each two-wire cable is connected to the main unit of the entrance cordless handset 100, the extension monitor 300, or another door phone system. In FIG. 4, the case where the cable connection part 201-1 is connected to the main | base station of another door phone system is illustrated.

  The key input unit 202 includes a response button. When the response button is operated, the key input unit 202 outputs a signal indicating that to the control unit 207.

  The speaker 203 converts the analog audio data output from the audio I / F unit 205 into audio and outputs the audio.

  The microphone 204 collects surrounding sounds, converts them into analog sound data, and outputs the analog sound data to the sound I / F unit 205.

  The audio I / F unit 205 converts the digital audio data output from the control unit 207 into analog audio data, adjusts the signal level, and outputs the analog audio data to the speaker 203. The audio I / F unit 205 adjusts the signal level of the analog audio data output from the microphone 204, converts the analog audio data into digital audio data, and outputs the digital audio data to the control unit 207. Such analog / digital conversion is performed by an A / D, D / A converter (not shown).

  The audio I / F unit 205 outputs data obtained by performing predetermined audio compression processing on the data obtained by digitally converting the analog audio data output from the microphone 204 to the control unit 207 as digital audio data. May be. In addition, when the digital audio data output from the control unit 207 is data obtained by performing predetermined audio compression processing, the audio I / F unit 205 performs predetermined audio expansion processing on the data. To digital / analog conversion.

  The display unit 206 includes a liquid crystal display, reproduces digital video data output from the control unit 207, and displays an entrance video. When the digital video data output from the control unit 207 is data obtained by performing a predetermined moving image compression process, a predetermined moving image expansion process is performed on the data to display a video.

  The control unit 207 controls each unit of the door phone master device 200. In addition, the control unit 207 sends a transmission control section (SW CON) that indicates a transmission section that permits transmission and a reception section that permits reception to each transmission driver 210-i, each reception driver 211-i, and a routing control section. It outputs to 212.

  The first clock generation unit 231 of the control unit 207 is a clock for sampling received data, and is based on crystal oscillation and has a first frequency corresponding to n times the bit rate of the received data (for example, 48 MHz (n = 10)) clock (CLK) is generated and output to the synchronization detector 213 and the second clock generator 214.

The packet generation unit 232 of the control unit 207 generates a downlink packet for realizing a call with video. Specifically, the packet generation unit 232 appropriately divides the digital audio data output from the audio I / F unit 205 and writes it in the user data field of each slot, and an identifier unique to the own device (doorphone master device 200). (Hereinafter referred to as “own device ID _master ”) and the control data including the identifier of the communication partner device are written in the control data field of each slot. Further, the packet generation unit 232 writes the preamble data and the sync pattern in each slot, and generates a downlink packet (transmission data). Furthermore, the packet generation unit 232 generates a transmission enable signal (SSCS) and a transmission second frequency (for example, 4.8 MHz) clock (SSCK). Then, the packet generation unit 232 outputs the downlink packet to the transmission data processing unit 208 in synchronization with the transmission enable signal (SSCS) and the clock (SSCK).

  In addition, the packet generation unit 232 may output control data related to the operation of the doorphone master device 200 or the operation of the front door device 100 to the transmission data processing unit 208 as data to be transmitted to the front door device 100. . Such control data includes, for example, the camera operation (data rate, pan, tilt, light, shutter, filter, etc.) of the doorphone master unit 200 to the entrance slave unit 100 and various sensors provided in the entrance slave unit 100. A control signal for controlling the operation of the device from door phone parent device 200 is included. The control data includes a control signal for controlling the operation of a device (such as a gate electronic key) arranged outdoors via a wireless communication circuit or the like (not shown) provided in the entrance cordless handset 100. Is included.

  The packet generation unit 232 generates a downlink signal including a unique identifier assigned to the registration target device set by the identifier setting unit 235 at the time of initial registration of the devices such as the entrance slave device 100 and the extension monitor 300. .

  Note that, in a standby state in which data is not exchanged between the front door device 100 (or the extension monitor 300) and the intercom master device 200, the packet generation unit 232 does not generate a downlink packet. Further, when a predetermined event such as a response button being operated occurs in a standby state (during asynchronous communication), the packet generation unit 232 transmits a downstream packet (interrupt signal) in which preamble data, sync pattern, and control data are written. Generate. The preamble and sync pattern used in the interrupt signal during asynchronous communication are the same as those used during synchronous communication.

  When the data reproduction unit 233 of the control unit 207 receives the enable signal (SSCS) from the synchronization detection unit 213, the data reproduction unit 233 uses the second frequency clock (SSCK) output from the second clock generation unit 214, and the routing control unit 212. The upstream signal output from is demodulated to obtain the upstream packet. Then, the data reproducing unit 233 outputs the digital audio data included in the upstream packet to the audio I / F unit 205, outputs the digital video data included in the upstream packet to the display unit 206, and the sync pattern included in the upstream packet. Is output to the connection state detection unit 234.

  Further, when a predetermined event occurs in a standby state (during asynchronous communication) and an upstream signal (interrupt signal) is input, the data reproduction unit 233 demodulates the upstream signal to acquire an upstream packet, and is included in the upstream packet The sync pattern to be output is output to the connection state detection unit 234. The data reproduction unit 233 extracts the control data of the interrupt signal after confirming that the connection state detection unit 234 can accurately capture the interrupt signal. If the control data is a synchronization request, the intercom master device 200 shifts to a synchronization process with the entrance slave device 100 or the extension monitor 300.

  The connection state detection unit 234 of the control unit 207 stores the normal connection check sync pattern and the reverse connection check sync pattern, and converts the received data sync pattern output from the data reproduction unit 233 into the normal connection check sync pattern and Match with reverse connection check sync pattern. The connection state detection unit 234 determines that the two-wire cable is correctly connected when the received data sync pattern and the normal connection check sync pattern completely match, and the received data sync pattern and the reverse connection check sync pattern are determined. If the two completely match, it is determined that the two-wire cable is reversely connected. Then, the connection state detection unit 234 outputs an inversion control signal (INV CON) indicating the determination result to the transmission data inversion unit 209.

  The identifier setting unit 235 of the control unit 207 sets a unique identifier to be assigned to each registration target device at the time of initial registration of the devices such as the entrance slave device 100 and the extension monitor 300, and outputs the identifier to the packet generation unit 232. Recording is performed in the recording unit 215. Further, the identifier setting unit 235 reads the identifier recorded in the identifier recording unit 215 as necessary. Note that the identifier setting unit 235 returns the set identifier to the packet generation unit again when the receipt of the identifier is not input from the data reproducing unit 233 even after a predetermined time has elapsed since the identifier was transmitted. Output to H.232.

  When the transmission data processing unit 208 receives the enable signal (SSCS) from the packet generation unit 232, the transmission data processing unit 208 uses the second frequency clock (SSCK) output from the packet generation unit 232, and the downlink data output from the packet generation unit 232. Modulation processing is performed on the packet data to generate a downlink signal, which is output to the routing control unit 212.

  When the connection state detection unit 234 determines that the two-wire cable is reversely connected, the transmission data inverting unit 209 inverts the downlink signal output from the routing control unit 212 and outputs the inverted signal to the transmission driver 210-1. On the other hand, when the connection state detection unit 234 determines that the two-wire cable is a normal connection, the transmission data inversion unit 209 outputs the downlink signal output from the routing control unit 212 to the transmission driver 210-1 as it is.

  The transmission driver 210-1 transmits a downlink signal to the master unit of another door phone system via the cable connection unit 201-1 in the transmission section instructed by the switching control signal (SW CON) from the control unit 207. . The transmission driver 210-i (in this case, i is other than 1) transmits the downstream signal to the entrance via the cable connection unit 201-i in the transmission section instructed by the switching control signal (SW CON) from the control unit 207. It transmits to the subunit | mobile_unit 100 or the expansion monitor 300. FIG.

  The reception driver 211-i receives an upstream signal transmitted from the front cordless handset 100, the extension monitor 300, or the parent device of another door phone system via the cable connection unit 201-i. Then, the reception driver 211-i outputs an uplink signal to the routing control unit 212 in the reception period instructed by the switching control signal (SW CON) from the control unit 207.

  The routing control unit 212 transmits the uplink signal transmitted from the front door slave unit 100 and output from the reception driver 211-i to the master unit 200. When the destination signal is addressed to the master unit 200, the synchronization detection unit 213, the second clock generation unit 214, the data reproduction If it is addressed to the expansion monitor 300, it is output to the corresponding transmission driver 210-i. In addition, the routing control unit 212 outputs the downlink signal output from the transmission data processing unit 208 and addressed to the entrance slave device 100 to the corresponding transmission driver 210-i. In addition, the routing control unit 212 outputs the uplink signal addressed to the entrance slave device 100 transmitted from the extension monitor 300 and output from the reception driver 211-i to the corresponding transmission driver 210-i. The routing control unit 212 controls routing (valid / invalid of communication routes). A specific example of routing control performed by the routing control unit 212 will be described later.

  The synchronization detection unit 213 uses the first frequency clock (CLK) output from the first clock generation unit 231 and uses the preamble data included in the uplink signal output from the routing control unit 212, to the entrance terminal 100. (The timing at the beginning of each bit of received data) is detected. Then, the synchronization detection unit 213 outputs a trigger signal serving as a reference for starting clock output to the second clock generation unit 214 at the timing when the unique pattern of the preamble data is detected, and an enable signal (SSCS) that permits the data reproduction operation Is output to the data reproducing unit 233.

  The second clock generation unit 214 corresponds to the bit rate of the received data based on the first frequency clock (CLK) output from the first clock generation unit 231 at the timing instructed by the synchronization detection unit 213. A clock (SSCK) having two frequencies (for example, 4.8 MHz) is generated, and a clock having the second frequency is output to the data reproducing unit 233.

The identifier storage unit 215 stores the own device ID _master and the identifiers of each device (the entrance slave device 100, the extension monitor 300, and the parent device of another door phone system).

<Configuration of additional monitor>
Next, the configuration of the extension monitor 300 will be described with reference to the block diagram of FIG. As illustrated in FIG. 5, the extension monitor 300 includes a cable connection unit 301, a key input unit 302, a speaker 303, a microphone 304, an audio I / F (interface) unit 305, a display unit 306, and a control unit 307. The control unit 307 includes a first clock generation unit 331, a packet generation unit 332, a data reproduction unit 333, and a connection state detection unit 334 inside. The expansion monitor 300 includes a transmission data processing unit 308, a transmission data inversion unit 309, a transmission driver 310, a reception driver 311, a reception data inversion unit 312, a synchronization detection unit 313, a second clock generation unit 314, and an identifier storage unit 315. Have.

  The cable connection unit 301 includes a connection terminal for a two-wire cable, and connects the one end on the additional monitor side of the two-wire cable to the reception driver 311 and the transmission driver 310 in a state where signals can be transmitted. Note that the other end of the two-wire cable is connected to the doorphone master unit 200.

  The key input unit 302 includes a call button. When the call button is operated, the key input unit 302 outputs a signal indicating that to the control unit 307.

  The speaker 303 converts analog audio data output from the audio I / F unit 305 into audio and outputs the audio.

  The microphone 304 collects ambient sound, converts it into analog sound data, and outputs it to the sound I / F unit 305.

  The audio I / F unit 305 converts the digital audio data output from the control unit 307 into analog audio data, adjusts the signal level, and outputs the analog audio data to the speaker 303. The audio I / F unit 305 adjusts the signal level of the analog audio data output from the microphone 304, converts the analog audio data into digital audio data, and outputs the digital audio data to the control unit 307. Such analog / digital conversion is performed by an A / D, D / A converter (not shown).

  Note that the audio I / F unit 305 outputs data obtained by performing predetermined audio compression processing on the data obtained by digitally converting the analog audio data output from the microphone 304 to the control unit 307 as digital audio data. May be. In addition, when the digital audio data output from the control unit 307 is data obtained by performing predetermined audio compression processing, the audio I / F unit 305 performs predetermined audio expansion processing on the data. To digital / analog conversion.

  The display unit 306 includes a liquid crystal display, reproduces the digital video data output from the control unit 307, and displays the entrance video. When the digital video data output from the control unit 307 is data obtained by performing a predetermined moving image compression process, the predetermined video expansion process is performed on the data to display a video.

  The control unit 307 controls each unit of the extension monitor 300. In addition, the control unit 307 outputs to the transmission driver 310 and the reception driver 311 a switching control signal (SW CON) instructing a transmission period that permits transmission and a reception period that permits reception.

  The first clock generation unit 331 of the control unit 307 is a clock for sampling received data, and is based on crystal oscillation and has a first frequency (for example, 48 MHz (n = 10)) clock (CLK) is generated and output to the synchronization detector 313 and the second clock generator 314.

The packet generation unit 332 of the control unit 307 generates an uplink packet for realizing a call with video. Specifically, the packet generation unit 332 appropriately divides the digital audio data output from the audio I / F unit 305 and writes the digital audio data in the user data field of each slot. Hereinafter, the control data including the “own device ID _monitor ” and the ID _master is written in the control data field of each slot. Further, the packet generation unit 332 writes preamble data and a sync pattern in each slot, and generates an uplink packet (transmission data). Further, the packet generation unit 332 generates a transmission enable signal (SSCS) and a transmission second frequency (for example, 4.8 MHz) clock (SSCK). Then, the packet generation unit 332 outputs the uplink packet to the transmission data processing unit 308 in synchronization with the transmission enable signal (SSCS) and the clock (SSCK).

  Note that the packet generation unit 332 does not generate an uplink packet in a standby state in which data is not transmitted / received between the extension monitor 300 and the intercom base unit 200. Further, when a predetermined event such as operation of a call button occurs in a standby state (during asynchronous communication), the packet generation unit 332 transmits an uplink packet (interrupt signal) in which preamble data, sync pattern, and control data are written. Generate. The preamble and sync pattern used in the interrupt signal during asynchronous communication are the same as those used during synchronous communication.

When the data reproduction unit 333 of the control unit 307 receives the enable signal (SSCS) from the synchronization detection unit 313, the data reproduction unit 333 uses the second frequency clock (SSCK) output from the second clock generation unit 314, and receives the data inversion unit. The downlink signal output from 312 is demodulated to obtain a downlink packet. Then, the data reproducing unit 333 outputs the digital video data included in the downlink packet to the display unit 306, outputs the digital audio data included in the downlink packet to the audio I / F unit 305, and the sync pattern included in the downlink packet. Is output to the connection state detection unit 334. Note that the data reproduction unit 333 causes the identifier storage unit 315 to store its own ID _monitor and ID _master included in the downlink packet at the time of initial registration.

  In addition, when a predetermined event occurs in a standby state (during asynchronous communication) and a downlink signal (interrupt signal) is input, the data reproduction unit 333 demodulates the downlink signal to acquire a downlink packet, and is included in the downlink packet The sync pattern is output to the connection state detection unit 334. The data reproducing unit 333 extracts the control data of the interrupt signal after confirming that the connection state detecting unit 334 has correctly captured the interrupt signal. If the control data is a synchronization request, the extension monitor 300 shifts to a synchronization process with the doorphone parent device 200.

  The connection state detection unit 334 of the control unit 307 stores the normal connection check sync pattern and the reverse connection check sync pattern, and converts the received data sync pattern output from the data reproduction unit 333 into the normal connection check sync pattern and Match with reverse connection check sync pattern. The connection state detection unit 334 determines that the two-wire cable is correctly connected when the sync pattern of the received data completely matches the sync pattern for the normal connection check, and the sync pattern of the received data and the sync pattern for the reverse connection check If the two completely match, it is determined that the two-wire cable is reversely connected. Then, the connection state detection unit 334 outputs an inversion control signal (INV CON) indicating the determination result to the transmission data inversion unit 309 and the reception data inversion unit 312.

  When the transmission data processing unit 308 receives the enable signal (SSCS) from the packet generation unit 332, the transmission data processing unit 308 uses the second frequency clock (SSCK) output from the packet generation unit 332, and the uplink data output from the packet generation unit 332. Modulation processing is performed on the packet data to generate an uplink signal, which is output to the transmission data inverting unit 309.

  When the connection state detection unit 334 determines that the two-wire cable is reversely connected, the transmission data inversion unit 309 inverts the uplink signal output from the transmission data processing unit 308 and outputs the inverted signal to the transmission driver 310. On the other hand, the transmission data inverting unit 309 outputs the uplink signal output from the transmission data processing unit 308 to the transmission driver 310 as it is when the connection state detection unit 334 determines that the two-wire cable is a normal connection.

  The transmission driver 310 transmits an upstream signal to the intercom base unit 200 via the cable connection unit 301 in the transmission section instructed by the switching control signal (SW CON) from the control unit 307.

  The reception driver 311 receives the downlink signal transmitted from the doorphone master device 200 via the cable connection unit 301. Then, the reception driver 311 outputs the downlink signal to the reception data inversion unit 312 in the reception period instructed by the switching control signal (SW CON) from the control unit 307.

  When the connection state detection unit 334 determines that the two-wire cable is reversely connected, the reception data inversion unit 312 inverts the downlink signal output from the reception driver 311 so as to invert the synchronization detection unit 313 and the second clock generation unit. 314, and output to the data reproduction unit 333. On the other hand, when the connection state detection unit 334 determines that the two-wire cable is a positive connection, the reception data inversion unit 312 directly uses the downlink signal output from the reception driver 311 as the synchronization detection unit 313 and the second clock generation unit. 314, and output to the data reproduction unit 333.

  The synchronization detection unit 313 uses the first frequency clock (CLK) output from the first clock generation unit 331 and uses the preamble data included in the downlink signal output from the reception driver 311 to Synchronization (start timing of each bit of received data) is detected. Then, the synchronization detection unit 313 outputs a trigger signal serving as a reference for starting clock output to the second clock generation unit 314 at the timing when the unique pattern of the preamble data is detected, and an enable signal (SSCS) that permits the data reproduction operation Is output to the data reproduction unit 333.

  The second clock generation unit 314 corresponds to the bit rate of the received data based on the first frequency clock (CLK) output from the first clock generation unit 331 at the timing instructed by the synchronization detection unit 313. A clock (SSCK) having two frequencies (for example, 4.8 MHz) is generated and output to the data reproducing unit 333.

The identifier storage unit 315 stores the own device ID _monitor and the ID _master received from the intercom master device 200.

  Although not shown in the figure, the front door device 100, the doorphone master device 200, and the extension monitor 300 are, for example, a CPU (Central Processing Unit), a storage medium such as a ROM (Read Only Memory) storing a control program, a RAM (Random Access And a communication circuit. In this case, the function of each unit described above is realized by the CPU executing the control program.

<Example of modulation processing>
Next, an example of modulation processing performed by the transmission data processing unit 108 (208, 308) will be described with reference to FIGS. 6 and 7 show a case where the Manchester code is employed.

  The transmission data processing unit 108 (208, 308) generates one signal corresponding to each data (1 bit) of the packet for each cycle Tm. When the Manchester code is employed, the transmission data processing unit 108 (208, 308) generates a modulation signal 402 by causing the data 401 having the value “0” to rise from Low to High as shown in FIG. . Also, the transmission data processing unit 108 (208, 308) causes the data 411 having the value “1” to fall from High to Low, and generates a modulated signal 412.

  Then, as shown in FIG. 7, for the data string 421 of “0, 0, 1,..., 1, 0”, the transmission data processing unit 108 (208, 308) corresponds to the value of each bit. Thus, a modulation signal 422 having a rising edge or a falling edge is generated every period Tm.

<Example of preamble data>
Next, an example of preamble data used in the present embodiment will be described with reference to FIG.

  As shown in FIG. 8, the preamble data (4 bytes = 32 bits) used in the present embodiment has a pattern of “1” from the 1st byte to the 3rd byte, and the 4th byte from the beginning to the 6th bit is “1”. 1 ”, 7 bit is“ 0 ”, and 8 bit (last 1 bit) is“ 1 ”. Further, in this case, the first 1 bit of the sync pattern following the preamble data is “1”. As a result, the preamble data shown in FIG. 8 has a unique pattern in which the period between adjacent falling edges 501 from the 6th bit to the 8th bit of the 4th byte is longer than the others. Further, the H (High) period and the L (Low) period between adjacent falling edges 501 are longer than others. FIG. 8 shows the waveform of the preamble data after Manchester encoding.

  In the present embodiment, the preamble data may be inverted from that shown in FIG. That is, the preamble data (4 bytes = 32 bits) used in the present embodiment is a pattern of “0” from the first byte to the third byte, “0” from the first byte to the first 6 bits, and 7 bits. A pattern in which “1” and 8 bits (last 1 bit) are “0” may be used. In this case, the first 1 bit of the sync pattern following the preamble data is “0”.

<Internal configuration of synchronization detector>
Next, the details of the internal configuration of the synchronization detection unit 113 of the front door device 100 will be described with reference to FIG. In the description, FIGS. 10 and 11 are used together with FIG. 9 in order to facilitate understanding of the synchronization detection processing of the present embodiment. In the example of FIG. 10, the preamble data and its unique pattern are those shown in FIG. FIG. 10 shows a case where the first clock generation unit 131 generates a 48 MHz clock (CLK) and the second clock generation unit 114 generates a 4.8 MHz clock (SSCK).

  As illustrated in FIG. 9, the synchronization detection unit 113 includes a first unique pattern detection unit 151, a second unique pattern detection unit 152, and an enable signal generation unit 153.

  The first unique pattern detection unit 151 and the second unique pattern detection unit 152 store a first specified number (for example, “18” to “22”) of a clock for detecting a unique pattern.

  The first unique pattern detection unit 151 samples the preamble data included in the reception data output from the reception data inversion unit 112 using the clock of the first clock generation unit 131, and counts the clocks between adjacent falling edges. To do. The first unique pattern detection unit 151 determines that a unique pattern has been detected when the number of clocks between adjacent falling edges matches one of the first specified numbers. In the example of FIG. 10, the clock number “20” between adjacent falling edges 501 matches one of the first specified numbers. Then, the first unique pattern detection unit 151 outputs a signal indicating that to the enable signal generation unit 153 at a predetermined timing.

  The second unique pattern detection unit 152 samples the preamble data included in the reception data output from the reception data inversion unit 112 at the same timing as the first unique pattern detection unit 151, and clocks between adjacent rising edges Count. The second unique pattern detection unit 152 determines that a unique pattern has been detected when the number of clocks between adjacent rising edges matches one of the first specified numbers, and outputs a signal indicating that detection to the enable signal generation unit To 153.

  When the enable signal generation unit 153 receives a signal indicating that a unique pattern has been detected from either the first unique pattern detection unit 151 or the second unique pattern detection unit 152, the trigger that becomes a reference for starting clock output The signal is output to the second clock generation unit 114, and the enable signal for permitting the data recovery operation is output to the data recovery unit 133 of the control unit 107 (in the example of FIG. 10, the enable signal SSCS is lowered and L (Low) Signal (activate).

  The unique pattern detection will be described in more detail with reference to FIG. FIG. 11A shows a unique pattern of normal polarity and a received waveform in the vicinity thereof when the two-wire cable is positively connected, and (1) in FIG. 11A is obtained by the first unique pattern detection unit 151. The number of clocks to be counted is shown, and (2) in FIG. 11A shows the number of clocks counted by the second unique pattern detection unit 152. FIG. 11 (B) shows a unique pattern with reversed polarity when the two-wire cable is reversely connected and a received waveform in the vicinity thereof. (1) in FIG. 11 (B) is obtained by the first unique pattern detection unit 151. The number of clocks to be counted is shown, and (2) in FIG. 11B shows the number of clocks counted by the second unique pattern detection unit 152.

  When the two-wire cable is positively connected, as shown in (1) of FIG. 11A, the number of clocks counted in the first unique pattern detection unit 151 is between adjacent falling edges of the unique pattern 1. “20”, which matches one of the first specified numbers, and “10” between other adjacent falling edges, and does not match any of the first specified numbers. When the first unique pattern detection unit 151 detects the unique pattern 1, the enable signal generation unit 153 causes the enable signal (SSCS) to fall (activate) at a predetermined position Z. On the other hand, as shown in (2) of FIG. 11A, the number of clocks counted by the second unique pattern detection unit 152 is “10” or “15” between any adjacent rising edges, It does not match any of the specified numbers. For this reason, the second unique pattern detection unit 152 cannot detect a unique pattern. As described above, when the two-wire cable is positively connected, the unique pattern 1 having a unique sampling clock number is unique in the synchronization detection unit 113 (the first unique pattern detection unit 151 and the second unique pattern detection unit 152). Detected.

  When the two-wire cable is reversely connected, the number of clocks counted by the second unique pattern detection unit 152 is “between adjacent rising edges of the unique pattern 2” as shown in (2) of FIG. 20 ”, which matches one of the first specified numbers, and“ 10 ”between other adjacent rising edges, and does not match any of the first specified numbers. When the second unique pattern detection unit 152 detects the unique pattern 2, the enable signal generation unit 153 causes the enable signal (SSCS) to fall (activate) at a predetermined position Y. On the other hand, as shown in (1) of FIG. 11B, the number of clocks counted by the first unique pattern detection unit 151 is “10” or “15” between any adjacent falling edges, Does not match any of the first specified number. For this reason, the first unique pattern detection unit 151 cannot detect a unique pattern. As described above, when the two-wire cable is reversely connected, the unique pattern 2 having a unique sampling clock number is unique in the synchronization detection unit 113 (the first unique pattern detection unit 151 and the second unique pattern detection unit 152). Detected.

  Note that the reception waveform in FIG. 11B is an inversion of the reception waveform in FIG. 11A, and the number of clocks between falling edges is the first specified number when the polarity is normal. When there is a pattern, there is inevitably a unique pattern in which the number of clocks between rising edges becomes the first specified number when the polarity is inverted. In this case, the arrangement positions and timings of the unique pattern 1 and the unique pattern 2 are the same, and the timings of the positions Z and Y at which the enable signal (SSCS) falls (activates) coincide.

  In this case, the second clock generation unit 114 is a data inversion point that is an edge (a waveform edge between the preamble data and the sync pattern) at which the reception waveform changes next from the timing when the trigger signal is input from the enable signal generation unit 153. The clock of the first frequency (48 MHz) from 511 (k is a natural number, k = 2 in the examples of FIGS. 10 and 11) is set as the start timing (t1 in FIG. 10), and the clock of the second frequency is Output.

  The data reproduction unit 133 decodes at the rising timing (t1 in FIG. 10) of the second frequency clock (SSCK) output from the second clock generation unit 114. That is, the data reproducing unit 133 performs decoding at the decoding timing 512 of the clock (CLK) of the k-th first frequency (48 MHz) from the data inversion point 511 that is the boundary between the preamble data and the sync pattern.

  In FIG. 12, when the timing of the data inversion point 511 and the clock of the first frequency (48 MHz) coincide with each other, the ideal clock 521, the case where the clock is advanced by 0.5 clock from the ideal clock 521, the maximum advance clock 522, the ideal clock A case where a delay of 0.5 clock from 521 is set as a maximum delay clock 523. In addition, the allowable range of crystal accuracy deviation from the communication partner is assumed to be one clock. The data recovery unit 133 is centered on the decoding timing 512 of the ideal clock 521, the timing 513 one clock before the decoding timing 512 of the maximum advance clock 522, and the timing one clock after the decoding timing 512 of the maximum delay clock 523. The received data can be correctly decoded within a section 531 (allowable range of data reading timing) between the terminal 514 and the terminal 514. In this case, if the duty ratio of the received waveform is between 30% and 70%, the data reproducing unit 133 can correctly decode the received data.

  In this way, it is possible to accurately calculate the variation in the data read timing by using the data inversion point as a reference, and by setting the data read timing each time the preamble bit of each slot is synchronized, the bit of the slot It is possible to obtain the maximum permissible value of the deviation of the data reading timing with the long length. As a result, asynchronous communication can be reliably performed within an allowable range of deviation between the crystal on the transmission side and the crystal on the reception side. As a result, the second clock generation unit 114 normally extracts the clock on the transmission side synchronized with the data included in the received data and uses it as the second frequency clock. In this embodiment, the second clock generation unit 114 uses the clock from the received data. Need not be extracted. For this reason, the circuit configuration can be simplified, and the cost can be suppressed.

  The internal configurations of the synchronization detection unit 213 of the doorphone master unit 200 and the synchronization detection unit 313 of the extension monitor 300 are also the same as the internal configuration of the synchronization detection unit 113 of the front door device 100 shown in FIG.

<Flow of synchronization detection processing>
Next, the flow of the synchronization detection process in the front door device 100 (synchronization detection unit 113, connection state detection unit 134) will be described with reference to FIG.

  In step S <b> 610, the synchronization detection unit 113 uses the first unique pattern detection unit 151 and the second unique pattern detection unit 152 to output the downlink before demodulation output from the reception driver 111 using the clock of the first clock generation unit 131. The preamble data contained in the signal is sampled, and the unique pattern of the preamble data is checked based on the number of clocks between adjacent falling edges and the number of clocks between adjacent rising edges.

  If the unique pattern can be detected (S620: YES), the flow proceeds to step S630 on the assumption that the bit synchronization can be established. If not detected (S620: NO), the flow returns to step S610 to return to the unique pattern. Check again.

  In step S630, the connection state detection unit 134 checks the sync pattern of the reception data output from the data reproduction unit 133.

  If the sync pattern of the received data matches the sync pattern for normal connection check (S640: YES), in step S650, the connection state detection unit 134 determines that the two-wire cable is a normal connection, and performs synchronization detection processing. finish.

  When the sync pattern of the received data matches the sync pattern for reverse connection check (S640: NO, S660: YES), in step S670, the connection state detection unit 134 determines that the two-wire cable is reverse connected. Then, the synchronization detection process ends.

  If the sync pattern of the received data does not match either the sync pattern for normal connection check or the sync pattern for reverse connection check (S640: NO, S660: NO), in step S680, the connection state detection unit 134 Determines that the sync pattern detection has failed, returns the flow to step S610, and checks the unique pattern again.

<Sequence until initial registration>
Next, a sequence until initial registration according to the present embodiment will be described with reference to FIG.

  When the entrance cordless handset 100 and the doorphone master set 200 are connected with a two-wire cable and the power is turned on (S701), the doorphone master set 200 writes registration start information in the control data field for the entrance cordless handset 100. The interrupt signal is transmitted (S702).

  The front door device 100 captures the interrupt signal from the door phone master device 200 and checks the control data (registration start information) of the interrupt signal (S703). The capture of the interrupt signal specifically means that the interrupt signal is sampled using the first frequency clock, the unique pattern in the preamble is detected, bit synchronization is established, and the second frequency clock is set. It is used to reproduce the interrupt signal and detect the sync pattern.

  Further, the entrance unit 100 detects the inversion of the two-wire cable (judgment of normal connection / reverse connection) using the sink pattern of the interrupt signal, and when the two-wire cable is in the reverse connection, the transmission data inversion unit 109 Then, inversion setting is performed for the reception data inversion unit 112 (S704).

  Thereafter, the front door device 100 transmits an interrupt signal in which the confirmation of receipt of the registration start information is written in the control data field to the intercom base device 200 (S705).

  The intercom master device 200 captures the interrupt signal from the entrance slave device 100 and confirms the control data (registration start information receipt) of the interrupt signal (S706).

  Then, the intercom master device 200 transmits an interrupt signal in which the unique identifier (terminal ID) assigned to the front door slave device 100 is written in the control data field (S707).

  The front door device 100 confirms the control data (terminal ID) of the interrupt signal, and transmits the interrupt signal in which the receipt confirmation of the terminal ID is written in the control data field to the doorphone master device 200 (S708).

  Through the above processing, the initial registration is completed (S709).

<Sequence from standby state to communication state>
Next, a sequence from the standby state (during asynchronous communication) to the communication state according to the present embodiment will be described with reference to FIG. FIG. 15 shows a sequence in the case where the front cordless handsets 100-1 and 100-2 and the extension monitor 300 are connected to the doorphone master phone 200.

  In a standby state (at the time of asynchronous communication) in which data is not transmitted / received between each device and the door phone master unit 200 (S801), when the call button of the entrance slave unit 100-2 is operated (S802), the entrance slave unit 100- 2 performs a synchronization request by transmitting an interrupt signal in which the synchronization request is written in the control data field to the intercom base unit 200 (S803).

  The intercom master device 200 captures the interrupt signal (S804) and confirms the synchronization request included in the interrupt signal. The capture of the interrupt signal specifically means that the interrupt signal is sampled using the first frequency clock, the unique pattern in the preamble is detected, bit synchronization is established, and the second frequency clock is set. It is used to reproduce the interrupt signal and detect the sync pattern.

  Upon confirming the synchronization request from the entrance slave device 100-2, the intercom master device 200 determines the frame timing for synchronous communication with each device (S805), and transmits a synchronization slot signal to each device (S806).

  Each device synchronizes with the doorphone master device 200 in accordance with the synchronization slot signal (S807). As a result, the respective devices and the intercom master device 200 are in a synchronized state (S808).

  Thereafter, the front door device 100-2 makes an image connection request by transmitting an upstream packet in which the image connection request is written in the control data field to the parent device 200 (S809). When confirming the image connection request, the door phone main unit 200 confirms the image connection by transmitting the downlink packet in which the image connection confirmation is written in the control data field to the front door device 100-2 (S810). Thereafter, the entrance handset 100-2 transmits image data to the doorphone master 200 by an uplink packet, and the doorphone master 200 enters an image data communication state in which the image data is displayed (S811). Note that the image data transmitted from the front door slave 100-2 is broadcast from the doorphone master 200 to other devices (the front door slave 100-1, the extension monitor 300). Can be displayed.

<Operation of each device>
Next, the operation of each device will be described.

<Operation of entrance cordless handset>
FIG. 16 is a flowchart showing an example of the operation of the front door device 100.

  In step S1010, the control unit 107 determines whether the call button has been operated. When the call button is operated (S1010: YES), the control unit 107 advances the flow to step S1020, and when not operated (S1010: NO), advances the flow to step S1100 described later.

  In step S <b> 1020, control unit 107 transmits a calling signal to door phone parent device 200.

  In step S1030, control unit 107 determines whether a response signal has been received from intercom master device 200 or not. When the response signal is not received (S1030: NO), the control unit 107 returns the flow to step S1020, and when the response signal is received (S1030: YES), the control unit 107 advances the flow to step S1040. Note that if the control unit 107 does not receive a response signal even if the call signal is transmitted a predetermined number of times, the control unit 107 may advance the flow to step S1100 described later.

  In step S <b> 1040, the control unit 107 starts audio input and video shooting using the microphone 104, the audio I / F unit 105, and the camera unit 106. In addition, the control unit 107 uses the packet generation unit 132 and the transmission data processing unit 108 to start packetizing and encoding various data (control data / digital audio data / digital video data) to be transmitted. Note that the control unit 107 may perform transmission rate control of digital audio data and digital video data.

  In step S1050, control unit 107 determines whether or not it is a slave unit side transmission section. If it is a transmission interval (S1050: YES), the control unit 107 advances the flow to step S1060. If not (S1050: NO), the control unit 107 advances the flow to step S1070 described later.

  In step S <b> 1060, control unit 107 uses transmission driver 110 to transmit the upstream signal generated by encoding to door phone parent device 200 via a two-wire cable. In addition, the control part 107 stops transmission of an uplink signal when a transmission area is complete | finished.

  In step S1070, control unit 107 determines whether or not it is a parent device side transmission section. When it is a transmission section (S1070: YES), the control unit 107 advances the flow to step S1080. When it is not a transmission section (S1070: NO), the control section 107 advances the flow to step S1090 described later.

  In step S1080, the control unit 107 starts receiving a downlink signal, extracting various data (control data / audio data), and outputting audio. Note that the control unit 107 stops receiving a downlink signal or extracting various data when the transmission period ends.

  In step S <b> 1090, control unit 107 determines whether or not the call between entrance slave device 100 and doorphone master device 200 has ended. For example, the control unit 107 determines that the call has ended when it receives a signal indicating that a call end operation has been performed on the doorphone base unit 200 from the doorphone base unit 200. If the call has not ended (S1090: NO), control unit 107 returns the flow to step S1050. If the call has ended (S1090: YES), control proceeds to step S1100.

  In step S1100, control unit 107 determines whether or not an instruction to end processing related to the door phone function has been given. For example, when the control unit 107 receives a signal indicating that the operation of stopping the door phone function has been performed on the doorphone master unit 200 from the doorphone master unit 200, the control unit 107 determines that the end of the process has been instructed. If the end of the process is not instructed (S1100: NO), the control unit 107 returns the flow to step S1010, and if instructed to end the process (S1100: YES), ends the series of processes.

<Operation of doorphone master unit>
FIG. 17 is a flowchart showing an example of the operation of the doorphone parent device 200.

  In step S2010, the control unit 207 determines whether a call signal has been received from the front door device 100. When the call signal is received (S2010: YES), the control unit 207 advances the flow to step S2020. When the call signal is not received (S2010: NO), the control unit 207 advances the flow to step S2090 described later.

  In step S2020, the control unit 207 transmits a response signal to the front door device 100 and outputs a ringing tone using the voice I / F unit 205 and the speaker 203.

  In step S2030, the control unit 207 starts voice input using the microphone 204 and the voice I / F unit 205. In addition, the control unit 207 uses the packet generation unit 232 and the transmission data processing unit 208 to start packetizing and encoding various data (control data / digital audio data) to be transmitted. Note that the control unit 207 may perform digital audio data transmission rate control.

  In step S2040, control unit 207 determines whether or not it is a slave unit side transmission section. The control unit 207 advances the flow to step S2050 if it is a transmission interval (S2040: YES), and advances the flow to step S2060 described later if it is not a transmission interval (S2040: NO).

  In step S2050, the control unit 207 starts receiving an upstream signal and extracting various data (control data / audio data / video data). In addition, the control unit 207 uses the audio I / F unit 205, the speaker 203, and the liquid crystal display to start outputting audio and video. Note that the control unit 207 stops receiving the uplink signal or extracting various data when the transmission period ends.

  In step S2060, the control unit 207 determines whether or not it is a parent device side transmission section. When it is a transmission section (S2060: YES), the control unit 207 advances the flow to step S2070. When it is not a transmission section (S2060: NO), the control section 207 advances the flow to step S2080 described later.

  In step S2070, the control unit 207 uses the transmission driver 210 to transmit the downlink signal generated by encoding to the front door device 100 via the two-wire cable. However, it is desirable that the control unit 207 does not transmit digital audio data until the response button is operated as described above. Note that the control unit 207 stops the transmission of the downlink signal when the transmission period ends.

  In step S2080, control unit 207 determines whether or not the telephone conversation between entrance slave device 100 and doorphone master device 200 has ended. For example, the control unit 207 determines that the call is ended when it is detected that an operation for ending the call is performed on the intercom base unit 200. In addition, it is desirable that the control unit 207 transmits a signal indicating that to the entrance terminal 100 when an operation for terminating the call is performed. If the call has not ended (S2080: NO), control returns to step S2040. If the call has ended (S2080: YES), control proceeds to step S2090.

  In step S2090, control unit 207 determines whether an instruction to end the process related to the door phone function has been given. For example, when the control unit 207 detects that the doorphone function stop operation has been performed on the doorphone master unit 200, the control unit 207 determines that the end of the process has been instructed. In addition, when the operation of stopping the door phone function is performed, the control unit 207 desirably transmits a signal indicating that to the front door device 100. If the control unit 207 is not instructed to end the process (S2090: NO), the control unit 207 returns the flow to step S2010, and if instructed to end the process (S2090: YES), ends the series of processes.

<Routing control during normal operation>
Next, a specific example of the routing control during the normal operation of door phone parent device 200 according to the present embodiment will be described with reference to FIGS. In the example of FIG. 18, the intercom base unit 200 (control unit 207 (described as “base unit control unit” in FIG. 18)) is one of the DRVs (set of transmission driver (Tx) and reception driver (Rx)) 1 ˜5, a case where five devices (the entrance slave device 100, the extension monitor 300, and the parent device of another door phone system) are connected is shown. In this case, seven types of setting patterns (P1 to P7) are prepared. FIG. 19 is a diagram illustrating an internal configuration of the routing control unit 212. As illustrated in FIG. 19, the routing control unit 212 includes a changeover switch 2121 and an OR circuit 2122 inside.

  The setting pattern P1 indicates routing (valid / invalid of communication route) in a standby state in which the intercom base unit 200 is not transmitting / receiving data to / from any device. In the setting pattern P1, the intercom base unit 200 is in a reception mode (a mode in which only reception is performed without transmission), and the control unit 207 is in the reception mode as shown in FIG. The terminal T3 of the changeover switch 2121 is connected to T2, the reception driver (Rx) of each DRV is enabled so that data reception from each device is possible, and an interrupt from each connected device is awaited. . In the setting pattern P1, in the state of waiting for an interrupt from each connected device, the outputs of all DRV reception drivers (Rx) are set to “L”.

  When an asynchronous interrupt signal is received from any device in the standby state, door phone parent device 200 establishes synchronization with the device that transmitted the interrupt signal. For example, when receiving an interrupt signal from DRV1, door phone parent device 200 establishes synchronization with a device connected to DRV1, and transmits and receives data (shifts to P2 (during transmission) or P3 (during reception)).

  The setting pattern P2 indicates routing at the time of simultaneous transmission (Broadcast) in which the doorphone parent device 200 transmits data to all devices. In the setting pattern P2, the door phone base unit 200 is in a transmission mode (a mode in which only transmission is performed without reception), and the control unit 207 connects the terminal T3 of the changeover switch 2121 to the terminal T1, and transmits data to each device. The transmission driver (Tx) of each DRV is enabled so that transmission is possible. At this time, even if data is transmitted from any device to the intercom base unit 200, it cannot be received by each DRV, and the base unit 200 discards the data. In the setting pattern P2, the intercom base unit 200 transmits data to all connected devices, but only the identifier of the communication partner device is described in the control data field of the downstream packet. Other devices discard data even if they are received. In the setting pattern P2, the outputs of all DRV reception drivers (Rx) are set to “L”.

  Setting patterns P3 to P7 indicate routing at the time of individual reception in which the intercom master device 200 receives data from any one device. In the setting patterns P3 to P7, the intercom base unit 200 is in the reception mode, and the control unit 207 connects the terminal T3 of the changeover switch 2121 to the terminal T2, and sets one DRV reception driver (Rx) corresponding to each setting pattern. Enable the other DRV transmission driver (Tx). Thereby, the intercom base unit 200 outputs the data received from the DRV for which the reception driver (Rx) is selected to the control unit 207 (CPU) in the routing control unit 212, and at the same time, transmits the data as it is to the transmission driver ( Tx) can be broadcast to other devices connected to all selected DRVs. Therefore, it is not necessary to decode and analyze the received data when performing broadcast transmission. Note that the outputs of the reception drivers (Rx) of all DRVs for which the transmission driver (Tx) is selected are “L”.

  For example, when the intercom 200 receives data from the DRV 2 from the DRV 2, the control unit 207 enables the DRV 2 reception driver (Rx) and enables other DRV transmission drivers (Tx). . In this case, the data from the entrance slave unit 100 is received from the DRV 2, passes through the OR circuit 2122 of the routing control unit 212, and is output to the control unit 207 for decoding. Further, the data that has passed through the OR circuit 2122 is transmitted to the DRVs 1, 3, 4, and 5 via the changeover switch 2121 and is broadcast to each connected device. At that time, only the reception driver (Rx) is valid for DRV2, and the transmission driver (Tx) is invalid. Therefore, the data passing through the OR circuit 2122 is not broadcast from DRV2. At this time, even if data is transmitted from another device to the intercom base unit 200, it cannot be received by the DRVs 1, 3, 4, 5 and the base unit 200 discards the data.

<Routing control during initial registration>
Next, a specific example of the routing control at the time of initial registration of the doorphone parent device 200 according to the present embodiment will be described with reference to FIGS. 19 and 20. In the example of FIG. 20, a case where the doorphone master unit 200 (the control unit 207 (described as “master unit control unit” in FIG. 20)) is connected to five devices via any one of the DRVs 1 to 5. Show. In this case, five types of setting patterns (EP1 to EP5) are prepared.

  The setting patterns EP1 to EP5 indicate routing at the time of initial registration in which any one device is registered by the doorphone parent device 200. In the setting patterns EP1 to EP5, the intercom base unit 200 is in the transmission mode, and the control unit 207 connects the terminal T3 of the changeover switch 2121 to the terminal T1, and enables the DRV transmission driver (Tx) corresponding to the registration target device. And enable other DRV reception drivers (Rx). Thereby, intercom master 200 can transmit a packet only to a registration target device without transmitting a packet to a device other than a registration target in a section in which the packet is transmitted. At this time, other DRV reception drivers (Rx) are enabled. However, when the doorphone parent device 200 is transmitting, the logic is to block reception of packets from all devices, and packets from those DRVs are used. (The control unit 207 selects transmission by SPI-RW). Note that the settings from P3 to P7 in FIG. 18 are used for transmission of packets from each registration target device to the intercom master device 200. In this case, the broadcast transmission function to other connected devices works, but since the transmission is only to the doorphone parent device 200, the other connected devices ignore this. Thereby, door phone main unit 200 can communicate one-to-one with a registration target device such as each front unit 100. Note that the outputs of the reception drivers (Rx) of all DRVs for which the transmission driver (Tx) is selected are “L”. When the DRV reception driver (Rx) is selected and waiting for an interrupt from each connected device, the output of the reception driver (Rx) is “L”.

<Effects of the present embodiment>
As described above, in this embodiment, a unique pattern in which the number of sampling clocks between adjacent falling edges or between adjacent rising edges is unique is detected. As a result, synchronization can be maintained even if a deviation occurs in the duty ratio of the received waveform.

<Variation of synchronization detection processing>
In the present embodiment, it is possible to further improve the detection accuracy of the unique pattern by using the repeated pattern from the beginning of the preamble data. Hereinafter, this variation will be described with reference to FIG. In the following description, it is assumed that the preamble data and its unique pattern are those shown in FIG. In other words, the preamble data has a pattern of “1” from the 1st byte to the 3rd byte, the 4th byte is “1” from the first 6 bits, the 7th bit is “0”, and the 8th bit (last 1 bit) is “1”. ] Pattern.

  In the synchronization detection unit 113a shown in FIG. 21, the same components as those in the synchronization detection unit 113 shown in FIG. The synchronization detection unit 113a illustrated in FIG. 21 employs a configuration in which a repeated pattern number detection unit 154 is added as compared with the synchronization detection unit 113 illustrated in FIG.

  The repetitive pattern number detection unit 154 includes a second prescribed number (for example, “8” to “12”) of clocks for detecting between adjacent falling edges other than the unique pattern (or between adjacent rising edges), and A third specified number (for example, “16”) for repetitive pattern detection is stored. The repetitive pattern number detection unit 154 uses the first counter to count clocks between adjacent falling edges of the preamble waveform (or between adjacent rising edges), and the number of clocks is set to one of the second specified numbers. If they match, the second counter is counted up. Then, when the count value of the second counter reaches the third specified number, the repeated pattern number detection unit 154 starts to operate with respect to the first unique pattern detection unit 151 and the second unique pattern detection unit 152. A trigger signal is output to indicate

  The first unique pattern detection unit 151 and the second unique pattern detection unit 152 start to operate after inputting a trigger signal from the repeated pattern number detection unit 154.

<Flow of synchronization detection processing variation>
Next, a flow of variations of the synchronization detection process will be described with reference to FIG. In the flow shown in FIG. 22, the steps common to the flow shown in FIG. 13 are denoted by the same reference numerals as those in FIG. The flow shown in FIG. 22 adopts a configuration in which steps S601 and S602 are added before step S610 of the flow shown in FIG.

  In step S601, the synchronization detection unit 113a samples the preamble data included in the downlink signal before demodulation output from the reception driver 111 with the clock of the first clock generation unit 131 by the repetition pattern number detection unit 154, Counting is performed when the number of clocks between falling edges (or between adjacent rising edges) matches one of the second specified numbers.

  Step S601 is repeated until the count value reaches the third specified number (S602: NO). When the count value reaches the third specified number (S602: YES), the flow proceeds to step S610 in order to start the unique pattern detection.

  As described above, in this variation, unique pattern detection is started on the condition that the number of preamble repetition patterns has reached the third specified number. As a result, the communication line DC bias fluctuation in the initial state, the communication line polarity change due to the differential characteristics, the communication waveform change in the communication waiting state due to the software state change, the communication waveform disturbance due to sudden noise, etc. Even when a pseudo-unique pattern is accidentally generated, erroneous synchronization can be prevented, and highly accurate bit synchronization can be realized.

  In the above description of the variation, the case where the repeated pattern number detection unit 154 is added to the synchronization detection unit 113a has been described. However, the present invention is not limited to this, and the first unique pattern detection unit 151 or the second unique pattern detection unit 113a is added. In the pattern detection unit 152, the function of the repeated pattern number detection unit 154 described above can be realized.

  In the above description, the image data from the entrance slave device 100 is broadcast to a plurality of devices such as the master device 200, the extension monitor 300, and the master device of another door phone system, and the images are simultaneously displayed on each device. However, the present invention is not limited to this. For example, an emergency message is generated by a process such as long-pressing a call button of the front door 100, and the emergency message is broadcast to a plurality of devices. An alarm may be output from each device. In the present embodiment, the connection between connected devices such as the door phone master device 200 and the entrance slave device 100 is described as an example, but the present invention is not limited to this. For example, the same effect can be obtained even if the other application device is a control device (communication device) such as a business phone (between an extension telephone and a control device) or a home security device (between various sensor nodes and a control device). .

  The present disclosure is suitable for use in a door phone system including an entrance child device with a camera and a door phone parent device.

DESCRIPTION OF SYMBOLS 1 Door phone system 100 Entrance unit 101, 201, 301 Cable connection part 102, 202, 302 Key input part 103, 203, 303 Speaker 104, 204, 304 Microphone 105, 205, 305 Audio | voice I / F part 106 Camera part 107, 207, 307 Control unit 108, 208, 308 Transmission data processing unit 109, 209, 309 Transmission data inversion unit 110, 210, 310 Transmission driver 111, 211, 311 Reception driver 112, 312 Reception data inversion unit 113, 113a, 213, 313 Synchronization detection unit 114, 214, 314 Second clock generation unit 115, 215, 315 Identifier storage unit 131, 231, 331 First clock generation unit 132, 232, 332 Packet generation unit 133, 233, 333 Data reproduction unit 134 234, 334 Connection state detection unit 151 First unique pattern detection unit 152 Second unique pattern detection unit 153 Enable signal generation unit 154 Repeat pattern number detection unit 200 Doorphone master unit 206, 306 Display unit 212 Routing control unit 235 Identifier Setting section 300 Additional monitor

The communication method of the present disclosure is a communication method of a door phone system in which a parent device and a child device are connected via a two-wire cable, and packet signals are transmitted and received between the parent device and the child device by time division duplex. Then, the transmission side device transmits data in which the preamble is arranged at a predetermined position, and the reception side device including the first detection unit and the second detection unit receives the data transmitted from the transmission side device. The received data is sampled using a clock having a first frequency corresponding to n times (n is 1 or more) the bit rate of the received data , and an adjacent falling edge is detected in the first detector. based on the number of clocks between performs detection of a unique pattern in the preamble, the in the second detection unit, unique in the based on the number of clocks between adjacent rising edges preamble Performs turn detection, to establish the bit synchronization based on the detection of either one of the unique pattern of the first detector and the second detector, after the bit synchronization has been established, the first The received data is regenerated using a second frequency clock corresponding to the bit rate of the received data, which is generated based on the frequency clock.

Claims (28)

A slave unit of a door phone system that is connected to a master unit via a two-wire cable and transmits and receives packet signals to and from the master unit by time division duplex,
A receiving unit that receives data in which a preamble and a sync pattern are arranged at a predetermined position;
A first clock generator for outputting a clock having a first frequency corresponding to n times (n is 1 or more) the bit rate of the received data;
A second clock generation unit that outputs a clock of a second frequency corresponding to the bit rate of the received data, which is generated based on the clock of the first frequency;
A first unique pattern that samples the received data using the clock of the first frequency, detects a unique pattern in the preamble based on the number of clocks between adjacent falling edges, and establishes bit synchronization A detection unit;
Second unique pattern detection for sampling the received data using the clock of the first frequency and detecting a unique pattern in the preamble based on the number of clocks between adjacent rising edges to establish bit synchronization And
A data reproducing unit for reproducing the received data using a clock of the second frequency after bit synchronization is established in the first unique pattern detecting unit or the second unique pattern detecting unit;
A handset comprising The preamble includes the number of clocks between the adjacent falling edges counted by the first unique pattern detection unit and the interval between the adjacent rising edges counted by the second unique pattern detection unit. The number of clocks is unique in the unique pattern.
The subunit | mobile_unit of Claim 1. When the Manchester encoding is used, the preamble is a pattern in which the last 3 bits of the unique pattern are “1”, “0”, “1”, and all other bits are “1”, and the preamble data The first 1 bit of the sync pattern following is “1”.
The subunit | mobile_unit of Claim 1. When the Manchester encoding is used, the preamble is a pattern in which the last 3 bits of the unique pattern are “0”, “1”, “0”, and the other bits are all “0”, and the preamble data The first 1 bit of the sync pattern following is “0”.
The subunit | mobile_unit of Claim 1. The first unique pattern detection unit includes:
It is determined that a unique pattern is detected when the number of clocks between adjacent falling edges matches the first specified number,
The second unique pattern detector is
It is determined that a unique pattern is detected when the number of clocks between adjacent rising edges matches the first specified number.
The subunit | mobile_unit as described in any one of Claim 1 to 4. When the number of clocks between adjacent falling edges or between adjacent rising edges coincides with the second specified number, and when the count value reaches the third specified number, the first unique pattern detecting unit and the first Further comprising a repeated pattern number detection unit that instructs the unique pattern detection unit of 2 to detect the unique pattern,
The first unique pattern detection unit and the second unique pattern detection unit are:
The detection of the unique pattern is started after receiving an instruction from the repeated pattern number detection unit,
The subunit | mobile_unit of Claim 5. The first unique pattern detection unit includes:
When the number of clocks between adjacent falling edges coincides with the second specified number, the second unique pattern detection is started together with the detection of the unique pattern when the counted value reaches the third specified number Instructing the part to detect the unique pattern,
The second unique pattern detector is
Starting detection of the unique pattern after receiving an instruction from the first unique pattern detection unit;
The subunit | mobile_unit of Claim 5. The second unique pattern detector is
When the number of clocks between adjacent rising edges coincides with the second specified number, the first unique pattern detection unit starts to detect the unique pattern when the count value reaches the third specified number. To detect the unique pattern,
The first unique pattern detection unit includes:
Starting the detection of the unique pattern after receiving an instruction from the second unique pattern detection unit;
The subunit | mobile_unit of Claim 5. The second clock generation unit uses a reception clock extracted from reception data as a clock of the second frequency.
The subunit | mobile_unit as described in any one of Claim 1 to 8. A door phone system parent device connected to a child device via a two-wire cable and transmitting and receiving packet signals to and from the child device by time division duplexing,
A receiving unit that receives data in which a preamble and a sync pattern are arranged at a predetermined position;
A first clock generator for outputting a clock having a first frequency corresponding to n times (n is 1 or more) the bit rate of the received data;
A second clock generation unit that outputs a clock of a second frequency corresponding to the bit rate of the received data, which is generated based on the clock of the first frequency;
A first unique pattern that samples the received data using the clock of the first frequency, detects a unique pattern in the preamble based on the number of clocks between adjacent falling edges, and establishes bit synchronization A detection unit;
Second unique pattern detection for sampling the received data using the clock of the first frequency and detecting a unique pattern in the preamble based on the number of clocks between adjacent rising edges to establish bit synchronization And
A data reproducing unit for reproducing the received data using a clock of the second frequency after bit synchronization is established in the first unique pattern detecting unit or the second unique pattern detecting unit;
A master unit equipped with The preamble includes the number of clocks between the adjacent falling edges counted by the first unique pattern detection unit and the interval between the adjacent rising edges counted by the second unique pattern detection unit. The number of clocks is unique in the unique pattern.
The parent device according to claim 10. When the Manchester encoding is used, the preamble is a pattern in which the last 3 bits of the unique pattern are “1”, “0”, “1”, and all other bits are “1”, and the preamble data The first 1 bit of the sync pattern following is “1”.
The parent device according to claim 10. When the Manchester encoding is used, the preamble is a pattern in which the last 3 bits of the unique pattern are “0”, “1”, “0”, and the other bits are all “0”, and the preamble data The first 1 bit of the sync pattern following is “0”.
The parent device according to claim 10. The first unique pattern detection unit includes:
It is determined that a unique pattern is detected when the number of clocks between adjacent falling edges matches the first specified number,
The second unique pattern detector is
It is determined that a unique pattern is detected when the number of clocks between adjacent rising edges matches the first specified number.
The parent device according to any one of claims 10 to 13. When the number of clocks between adjacent falling edges or between adjacent rising edges coincides with the second specified number, and when the count value reaches the third specified number, the first unique pattern detecting unit and the first Further comprising a repeated pattern number detection unit that instructs the unique pattern detection unit of 2 to detect the unique pattern,
The first unique pattern detection unit and the second unique pattern detection unit are:
The detection of the unique pattern is started after receiving an instruction from the repeated pattern number detection unit,
The parent device according to claim 14. The first unique pattern detection unit includes:
When the number of clocks between adjacent falling edges coincides with the second specified number, the second unique pattern detection is started together with the detection of the unique pattern when the counted value reaches the third specified number Instructing the part to detect the unique pattern,
The second unique pattern detector is
Starting detection of the unique pattern after receiving an instruction from the first unique pattern detection unit;
The parent device according to claim 14. The second unique pattern detector is
When the number of clocks between adjacent rising edges coincides with the second specified number, the first unique pattern detection unit starts to detect the unique pattern when the count value reaches the third specified number. To detect the unique pattern,
The first unique pattern detection unit includes:
Starting the detection of the unique pattern after receiving an instruction from the second unique pattern detection unit;
The parent device according to claim 14. The second clock generation unit uses a reception clock extracted from reception data as a clock of the second frequency.
The parent device according to any one of claims 10 to 17. This is a door phone system monitor that is added to a door phone system consisting of a parent device and a child device, is connected to the parent device via a two-wire cable, and transmits and receives packet signals to and from the parent device by time division duplex. And
A receiving unit that receives data in which a preamble and a sync pattern are arranged at a predetermined position;
A first clock generator for outputting a clock having a first frequency corresponding to n times (n is 1 or more) the bit rate of the received data;
A second clock generation unit that outputs a clock of a second frequency corresponding to the bit rate of the received data, which is generated based on the clock of the first frequency;
A first unique pattern that samples the received data using the clock of the first frequency, detects a unique pattern in the preamble based on the number of clocks between adjacent falling edges, and establishes bit synchronization A detection unit;
Second unique pattern detection for sampling the received data using the clock of the first frequency and detecting a unique pattern in the preamble based on the number of clocks between adjacent rising edges to establish bit synchronization And
A data reproducing unit for reproducing the received data using a clock of the second frequency after bit synchronization is established in the first unique pattern detecting unit or the second unique pattern detecting unit;
A monitor comprising: The preamble includes the number of clocks between the adjacent falling edges counted by the first unique pattern detection unit and the interval between the adjacent rising edges counted by the second unique pattern detection unit. The number of clocks is unique in the unique pattern.
The monitor according to claim 19. When the Manchester encoding is used, the preamble is a pattern in which the last 3 bits of the unique pattern are “1”, “0”, “1”, and all other bits are “1”, and the preamble data The first 1 bit of the sync pattern following is “1”.
The monitor according to claim 19. When the Manchester encoding is used, the preamble is a pattern in which the last 3 bits of the unique pattern are “0”, “1”, “0”, and the other bits are all “0”, and the preamble data The first 1 bit of the sync pattern following is “0”.
The monitor according to claim 19. The first unique pattern detection unit includes:
It is determined that a unique pattern is detected when the number of clocks between adjacent falling edges matches the first specified number,
The second unique pattern detector is
It is determined that a unique pattern is detected when the number of clocks between adjacent rising edges matches the first specified number.
The monitor according to any one of claims 19 to 22. When the number of clocks between adjacent falling edges or between adjacent rising edges coincides with the second specified number, and when the count value reaches the third specified number, the first unique pattern detecting unit and the first Further comprising a repeated pattern number detection unit that instructs the unique pattern detection unit of 2 to detect the unique pattern,
The first unique pattern detection unit and the second unique pattern detection unit are:
The detection of the unique pattern is started after receiving an instruction from the repeated pattern number detection unit,
The monitor according to claim 23. The first unique pattern detection unit includes:
When the number of clocks between adjacent falling edges coincides with the second specified number, the second unique pattern detection is started together with the detection of the unique pattern when the counted value reaches the third specified number Instructing the part to detect the unique pattern,
The second unique pattern detector is
Starting detection of the unique pattern after receiving an instruction from the first unique pattern detection unit;
The monitor according to claim 23. The second unique pattern detector is
When the number of clocks between adjacent rising edges coincides with the second specified number, the first unique pattern detection unit starts to detect the unique pattern when the count value reaches the third specified number. To detect the unique pattern,
The first unique pattern detection unit includes:
Starting the detection of the unique pattern after receiving an instruction from the second unique pattern detection unit;
The monitor according to claim 23. The second clock generation unit uses a reception clock extracted from reception data as a clock of the second frequency.
The monitor according to any one of claims 19 to 26. A communication method of a door phone system in which a parent device and a child device are connected via a two-wire cable, and packet signals are transmitted and received between the parent device and the child device by time division duplex,
The sending device is
Send data with preamble in place,
The receiving device
Receiving data transmitted from the transmitting device;
Sampling the received data using a clock having a first frequency corresponding to n times the bit rate of the received data (n is 1 or more);
Bit synchronization is established by detecting a unique pattern in the preamble based on the number of clocks between adjacent falling edges or the number of clocks between adjacent rising edges,
After the bit synchronization is established, the received data is regenerated using a second frequency clock corresponding to the bit rate of the received data, which is generated based on the first frequency clock.
Communication method.

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