JP6474004B2 - Base unit and communication method - Google Patents

Description

  The present disclosure relates to a master unit 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 installed at a front door outside the home (hereinafter referred to as “entrance slave unit”) and a video image captured by the camera of the entrance slave unit are displayed 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 intercom master unit also transfers the data received from the entrance slave unit to the additional monitor. As a result, the same image data is broadcast to the doorphone master and the extension monitor, and the doorphone master and the extension monitor can display the same image data.

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. Furthermore, when the received data is transferred from the parent device to another device, the duty ratio shift increases, and a decoding error may occur in the transfer destination device. In the prior art, measures against decoding errors caused by the deviation of the duty ratio of the received waveform have not been studied.

  The purpose of this disclosure is to transfer the received waveform of each bit of the received data at the transfer source master unit even when there is a deviation in the duty ratio of the received waveform of the received data when transferring the received data. It is an object to provide a door phone system base unit and a door phone system communication method capable of correcting a duty ratio with high accuracy and correctly decoding received data in a transfer destination device.

  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 bit rate of received data A first clock generator that outputs a clock of a first frequency corresponding to n times (n is 1 or more), and a first clock generator corresponding to the bit rate of the received data generated based on the clock of the first frequency A second clock generation unit that outputs a clock of two frequencies, and decodes each bit of the received data using the clock of the second frequency to obtain decoded data, and also counts by the clock of the first frequency A reception data decoding unit that outputs a counter value at the time when the waveform of the reception data is inverted, and second reception data that is branched before being input to the reception data decoding unit and transferred for broadcast use The duty ratio of each bit comprises a duty ratio correcting section that corrects, based on the counter value, and a data reproduction unit for reproducing the decrypted data using a clock of the second frequency.

  A communication method of the present disclosure is a communication method of a master unit of a door phone system that is connected to a slave unit via a two-wire cable and transmits and receives packet signals to and from the slave unit by time-division duplex, The first frequency clock corresponding to n times the bit rate (n is 1 or more) is output, and the second frequency corresponding to the bit rate of the received data is generated based on the first frequency clock. A clock is output, each bit of the received data is decoded using the clock of the second frequency, the decoded data is reproduced using the clock of the second frequency, and counting by the clock of the first frequency is performed. The counter value at the time when the waveform of the received data is inverted is output, and each bit of the second received data that is branched from the received data before being decoded and transferred for broadcast use The duty ratio is corrected on the basis of the counter value.

  According to the present disclosure, when the received data is transferred, even if there is a deviation in the duty ratio of the received waveform of the received data, the received waveform of the received data for each bit of the received data at the transfer source master unit It is possible to correct the duty ratio with high accuracy and correctly decode the received data in the transfer destination device.

The system block diagram which shows the structure of the door phone system which concerns on one embodiment of this indication Frame configuration diagram showing frame configuration and time slot configuration according to an embodiment of the present disclosure Configuration diagram of an interrupt signal according to an embodiment of the present disclosure 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 reception data processing 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 explaining the timing adjustment process of the entrance cordless handset which concerns on one embodiment of this indication 1st figure explaining the decoding process of the entrance cordless handset which concerns on one embodiment of this indication 2nd figure explaining the decoding process of the entrance cordless handset which concerns on one embodiment of this indication FIG. 3 is a third diagram for explaining the decryption process of the entrance slave according to the embodiment of the present disclosure. 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 figure which shows the 1st example of the duty ratio correction | amendment process of the door phone main unit which concerns on one embodiment of this indication The flowchart which shows an example of operation | movement of the duty ratio correction | amendment process of the door phone main unit which concerns on one embodiment of this indication The figure which shows the 2nd example of the duty ratio correction | amendment process of the door phone main unit which concerns on one embodiment of this indication The figure which shows the 3rd example of the duty ratio correction | amendment process of the door phone main unit which concerns on one embodiment of this indication The block diagram which shows the internal structure of the reception data processing part of the entrance cordless handset which concerns on the variation 1 of one embodiment of this indication The 1st figure explaining detection of the unique pattern of the entrance cordless handset which concerns on the variation 1 of one embodiment of this indication The 2nd figure explaining the detection of the unique pattern of the entrance cordless handset which concerns on the variation 1 of one embodiment of this indication 1st block diagram which shows the internal structure of the reception data processing part of the entrance cordless handset which concerns on the variation 2 of one embodiment of this indication The flowchart which shows an example of operation | movement of the synchronous detection process which concerns on the variation 2 of one embodiment of this indication The 2nd block diagram showing the internal configuration of the reception data processing part of the entrance cordless handset concerning variation 2 of an embodiment of this indication

  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, time slot configuration>
Next, a frame configuration and a time 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 an area of 48000 bits, has a 10 ms period, a bit rate of 4.8 Mbps, and is divided into 24 time slots. Therefore, each time 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 time 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 time 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 sync pattern of the interrupt signal are the same as the time slot during 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. The front door device 100 includes a transmission data processing unit 108, a transmission data reversing unit 109, a transmission driver 110, a reception driver 111, a reception data reversing unit 112, a reception data processing unit 113, and an identifier storage unit 114.

  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 reception data processing unit 113.

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 in the user data field of each time slot. Control data including an identifier (hereinafter referred to as “own device ID _slave ”) unique to the own device (the entrance _slave device 100) and an identifier of the door phone master device 200 of the communication partner (hereinafter referred to as “ID _master ”) is _assigned to each time slot. Write to the control data field. Further, the packet generation unit 132 writes preamble data and a sync pattern in each time 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 reception data processing unit 113, the data reproduction unit 133 uses the second frequency clock (SSCK) output from the reception data processing unit 113, and receives the enable signal (SSCS). The digital audio data included in the downlink packet (decoded data) output from 113 is output to the audio I / F unit 105, and the sync pattern included in the downlink packet (decoded data) is output to the connection state detection unit 134. Note that the data reproduction unit 133 causes the identifier storage unit 114 to store the 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 indicated 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 and outputs the inverted signal to the reception data processing unit 113. On the other hand, the reception data inverting unit 112 outputs the downlink signal output from the reception driver 111 to the reception data processing unit 113 as it is when the connection state detection unit 134 determines that the two-wire cable is a normal connection.

  The reception data processing 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, the intercom base unit 200. (The timing at the beginning of each bit of received data) is detected. Then, the received data processing unit 113 outputs an enable signal (SSCS) for permitting the data reproduction operation to the data reproduction unit 133 at the timing when the unique pattern of the preamble data is detected.

  The reception data processing unit 113 also decodes the downlink signal (reception data) output from the reception data inversion unit 112 and outputs the decoded data to the data reproduction unit 133. Also, the reception data processing unit 113 uses the first frequency clock (CLK) output from the first clock generation unit 131 as a reference, and the second frequency (for example, 4.8 MHz) clock corresponding to the bit rate of the reception data. (SSCK) is generated and output to the data reproducing unit 133.

The identifier storage unit 114 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 base unit 200 includes a transmission data processing unit 208, a transmission data reversing unit 209, a transmission driver 210, a reception driver 211, a routing control unit 212, a reception data processing unit 213, and an identifier storage unit 214. 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 routing controller 212 and the received data processor 213.

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 time slot, and is unique to the own device (doorphone master device 200). Control data including an identifier (hereinafter referred to as “own device ID _master ”) and the identifier of the communication partner device is written in the control data field of each time slot. Furthermore, the packet generation unit 232 writes preamble data and a sync pattern in each time 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, camera operations (data rate, pan, tilt, light, shutter, filter, and other operations) from 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 reception data processing unit 213, the data reproduction unit 233 uses the second frequency clock (SSCK) output from the reception data processing unit 213, The digital audio data included in the upstream packet (decoded data) output from 213 is output to the audio I / F unit 205, the digital video data included in the upstream packet is output to the display unit 206, and the sync included in the upstream packet is output. The pattern 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. It is recorded in the storage unit 214. Further, the identifier setting unit 235 reads the identifier recorded in the identifier storage unit 214 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. The data is transmitted to the slave unit 100 or the expansion monitor 300.

  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 outputs the upstream signal transmitted from the front door slave device 100 and output from the reception driver 211-i to the reception data processing unit 213 when addressed to the parent device 200, and to the extension monitor 300. In some cases, the data 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). In addition, the routing control unit 212 corrects the duty ratio when the received data is transferred to the master unit of another door phone system. A specific example of routing control performed by the routing control unit 212 and details of the duty ratio correction process will be described later.

  The reception data processing 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. 100 (synchronization with the head of each bit of received data) is detected. Then, the reception data processing unit 213 outputs an enable signal (SSCS) for permitting the data reproduction operation to the data reproduction unit 233 at the timing when the unique pattern of the preamble data is detected.

  The reception data processing unit 213 decodes the uplink signal (reception data) output from the routing control unit 212 and outputs the decoded data to the data reproduction unit 233. The reception data processing unit 213 uses the first frequency clock (CLK) output from the first clock generation unit 231 as a reference, and the second frequency (for example, 4.8 MHz) clock corresponding to the bit rate of the reception data. (SSCK) is generated and output to the data reproduction unit 233.

  The reception data processing unit 213 outputs information related to the timing at which the waveform of the reception data is inverted to the routing control unit 212. Details of the configuration of the reception data processing unit 213 will be described later.

The identifier storage unit 214 stores the own device ID _master and the identifiers of the devices (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 reversing unit 309, a transmission driver 310, a reception driver 311, a reception data reversing unit 312, a reception data processing unit 313, and an identifier storage unit 314.

  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 received data processing unit 313.

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, writes it in the user data field of each time slot, and an identifier unique to the own device (additional monitor 300) (Hereinafter referred to as “own device ID _monitor ”) and the control data including the ID _master are written in the control data field of each time slot. Further, the packet generation unit 332 writes preamble data and a sync pattern in each time 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 reception data processing unit 313, the data reproduction unit 333 uses the second frequency clock (SSCK) output from the reception data processing unit 313, and receives the reception data processing unit. The digital video data included in the downlink packet (decoded data) output from 313 is output to the display unit 306, the digital audio data included in the downlink packet is output to the audio I / F unit 305, and the sync included in the downlink packet is output. The pattern is output to the connection state detection unit 334. Note that the data reproduction unit 333 causes the identifier storage unit 314 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 and outputs the inverted signal to the reception data processing unit 313. On the other hand, the reception data reversing unit 312 outputs the downlink signal output from the reception driver 311 to the reception data processing unit 313 as it is when the connection state detection unit 334 determines that the two-wire cable is a normal connection.

  The reception data processing 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, the intercom base unit 200. (The timing at the beginning of each bit of received data) is detected. Then, the reception data processing unit 313 outputs an enable signal (SSCS) for permitting the data reproduction operation to the data reproduction unit 333 at the timing when the unique pattern of the preamble data is detected.

  The reception data processing unit 313 decodes the downlink signal (reception data) output from the reception data inversion unit 312 and outputs the decoded data to the data reproduction unit 333. The reception data processing unit 313 uses the first frequency clock (CLK) output from the first clock generation unit 131 as a reference, and the second frequency (eg, 4.8 MHz) clock corresponding to the bit rate of the reception data. (SSCK) is generated and output to the data reproduction unit 333.

The identifier storage unit 314 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 the like. 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 received data processing unit>
Next, the details of the internal configuration of the reception data processing unit 213 of the doorphone parent device 200 will be described with reference to FIG. In the description, FIG. 10 is used in conjunction 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 256 generates a 4.8 MHz clock (SSCK).

  As shown in FIG. 9, the reception data processing unit 213 includes a first unique pattern detection unit 251, a second unique pattern detection unit 252, an enable signal generation unit 253, a timing adjustment unit 254, a reception data decoding unit 255, and a first A two-clock generation unit 256 is included.

  The reception data output from the reception data inversion unit 112 is input to the first unique pattern detection unit 251, the second unique pattern detection unit 252, the timing adjustment unit 254, and the reception data decoding unit 255. The clock (CLK) of the first clock generation unit 131 is input to the first unique pattern detection unit 251, the second unique pattern detection unit 252, the timing adjustment unit 254, the reception data decoding unit 255, and the second clock generation unit 256. Is done.

  The first unique pattern detection unit 251 and the second unique pattern detection unit 252 store a first specified number (for example, “18” to “22”) of clocks for detecting a unique pattern.

  The first unique pattern detection unit 251 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 251 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 251 outputs a signal indicating that to the enable signal generation unit 253 at a predetermined timing.

  The second unique pattern detection unit 252 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 251, and clocks between adjacent rising edges Count. The second unique pattern detection unit 252 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 an enable signal generation unit generates a signal indicating that detection Output to H.253.

  When the enable signal generation unit 253 receives a signal indicating that a unique pattern has been detected from either the first unique pattern detection unit 251 or the second unique pattern detection unit 252 (timing 510 in FIG. 10), data An enable signal for permitting the reproduction operation is output to the timing adjustment unit 254 and the data reproduction unit 133 (in the example of FIG. 10, the enable signal SSCS is lowered to be an L (Low) signal (is activated)).

  The timing adjustment unit 254 has a timing generation counter therein, and when the enable signal is input from the enable signal generation unit 253, detects the waveform edge of the first reception data (the first bit of the sync pattern). The first received data starts from a data inversion timing 511 that is a waveform edge between the preamble data and the sync pattern.

  Then, after detecting the waveform edge, the timing adjustment unit 254 performs counting by the timing generation counter with the clock of the first frequency, and observes the counter value at the timing of the waveform edge of each received data. When the counter value is different from the normal value, the timing adjustment unit 254 corrects the counter value and outputs the corrected counter value to the reception data decoding unit 255 and the second clock generation unit 256. As a result, the start timing of the data reproduction window range (range 502 in FIG. 10), which is a range in which the counter value becomes a predetermined value, is adjusted. Details of the counter value correction processing performed by the timing adjustment unit 254 will be described later.

  The reception data decoding unit 255 receives the counter value from the timing adjustment unit 254, scans and detects the logical inversion of the waveform for one bit of reception data within the range of the data reproduction window (range 502 in FIG. 10), and receives the reception data. The data corresponding to the logical inversion of the Manchester encoded waveform for one bit is decoded, and the decoded data is output to the data reproducing unit 133. In the example of FIG. 10, the received data decoding unit 255 outputs decoded data “1” when the waveform is inverted from “H” to “L” in the range 502, and the waveform is changed from “L” to “H”. When inverted, the decoded data “0” is output. At approximately the same time as the time when the second received data is input to the received data decoding unit 255, the decoded data of the leading received data is output from the received data decoding unit 255 with a certain delay. The reception data decoding unit 255 outputs information indicating the counter value at the time when the waveform of the reception data is inverted to the routing control unit 212. Details of the received data decoding process performed by the received data decoding unit 255 will be described later.

  The second clock generation unit 256 receives the counter value from the timing adjustment unit 254, and outputs SSCK (“L” in FIG. 10) with the counter value “0” (timing 512 in FIG. 10) of the second received data. ), The SSCK logic for the first decoded data after a certain delay is inverted from “L” to “H” with the counter value “5” of the first received data, and the counter of the second received data With the value “0”, the logic of SSCK at the boundary between the first decoded data and the second decoded data is inverted from “H” to “L”. Thereafter, the second clock generation unit 256 performs logical inversion from “H” to “L” at the count value “0” and “L” to “H” at the count value “5” for the recovered clock SSCK. Repeat logic inversion. Then, the second clock generation unit 256 outputs a clock (SSCK) of the second frequency (for example, 4.8 MHz) to the data reproduction unit 133 at the timing of logical inversion from “L” to “H”.

<Detailed description of unique pattern detection>
Next, detection of a unique pattern will be described in 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 251. 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 252. FIG. 11B 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. 11B is obtained by the first unique pattern detection unit 251. 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 252.

  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 251 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 251 detects the unique pattern 1, the enable signal generation unit 253 causes the enable signal (SSCS) to fall (activate) at a predetermined timing Z. On the other hand, as shown in (2) of FIG. 11A, the number of clocks counted by the second unique pattern detection unit 252 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 252 cannot detect a unique pattern. As described above, when the two-wire cable is positively connected, in the reception data processing unit 213 (the first unique pattern detection unit 251 and the second unique pattern detection unit 252), the unique pattern 1 whose sampling clock number is unique is Only detected.

  When the two-wire cable is reversely connected, as shown in (2) of FIG. 11B, the number of clocks counted in the second unique pattern detection unit 252 is “between adjacent rising edges of the unique pattern 2”. 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 252 detects the unique pattern 2, the enable signal generation unit 253 causes the enable signal (SSCS) to fall (activate) at a predetermined timing Y. On the other hand, as shown in (1) of FIG. 11B, the number of clocks counted in the first unique pattern detection unit 251 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 251 cannot detect a unique pattern. As described above, when the two-wire cable is reversely connected, the received data processing unit 213 (the first unique pattern detection unit 251 and the second unique pattern detection unit 252) has a unique pattern 2 with a unique sampling clock number. Only 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 Z and Y at which the enable signal (SSCS) falls (activates) coincide with each other (timing 510 in FIG. 10).

<Detailed description of counter value correction processing>
Next, details of the counter value correction processing performed by the timing adjustment unit 254 will be described with reference to FIG. FIG. 12A shows a case where the start waveform edge and the end waveform edge of the received data are not delayed. FIG. 12B shows a case where the waveform edge at the start of the received data is delayed by one sampling clock in the asynchronous metastable processing between the received data and the sampling clock of the first frequency. FIG. 12C shows a case where the waveform edge at the end of the received data is delayed by one sampling clock in the asynchronous metastable process between the received data and the sampling clock of the first frequency.

  The timing adjustment unit 254 detects the timing 511 of the first frequency immediately after detecting the waveform edge timing 511 at which the waveform edge of the first received data appears from the timing 510 when the enable signal (SSCS) becomes active after detecting the unique pattern of the preamble. Starts the operation of the timing generation counter that counts with the clock (48 MHz).

  In the case of FIG. 12A, there is no delay in the waveform edge at the start / end of the received data, and the waveform edge at the start of the second and subsequent received data is the timing value of the counter value “9” (normal value). It has become. In this case, the timing adjustment unit 254 does not correct the counter value, resets the timing generation counter with the counter value “9”, and starts counting with the value next to the count value “9” as the count value “0”. To do.

  In the case of FIG. 12B, the waveform edge at the start of the reception data is delayed by one sampling clock from the case of FIG. 12A, and the waveform edge at the start of the second reception data is the timing of the counter value “8”. It has become. In this case, the timing adjustment unit 254 resets the timing generation counter without counting the counter value “9”, and starts counting with the next value after the count value “8” as the count value “0”. Thus, the first sampling point (count value) of the data reproduction window of the second received data from the waveform edge (count value “8”) of the bit boundary between the first received data and the second received data in FIG. The time until “1”) can be adjusted to the case of FIG.

  In the case of FIG. 12C, the waveform edge at the end of the received data is delayed by one sampling clock from the case of FIG. 12A, and the waveform edge at the start of the second received data is the timing value of the counter value “0”. It has become. In this case, the timing adjustment unit 254 resets the timing generation counter to the count value “0”, then resets the timing generation counter again, and starts counting with the next value as the count value “0”. Accordingly, the first sampling point of the data reproduction window of the second received data from the waveform edge (count value: first “0”) of the bit boundary between the first received data and the second received data in FIG. The time until (count value “1”) can be adjusted to the case of FIG.

<Detailed description of received data decoding processing>
Next, details of the reception data decoding process performed by the reception data decoding unit 255 will be described with reference to FIGS. 13, 14, and 15. 13 corresponds to FIG. 12A, FIG. 14 corresponds to FIG. 12B, and FIG. 15 corresponds to FIG.

  13, 14, and 15, the received data decoding unit 255 performs the logic inversion of the waveform of 1 bit of received data in the range of the data reproduction window from the counter value “1” to “7”. Scan detection is performed, and data corresponding to the logical inversion of the Manchester encoded waveform for 1 bit of the received data is decoded. Specifically, the received data decoding unit 255 sets the value of the decoded data to “1” when the waveform is inverted from “H” to “L” in the range of the data reproduction window, and the waveform starts from “L”. When inverted to “H”, the value of the decoded data is set to “0”.

  The received data decoding unit 255 determines the value of the decoded data for each received data at the timing of the counter value “8”, and starts outputting decoded data after a certain delay at the timing of the next counter value “0”. Further, the output of the decoded data is continued until the point of a certain delay corresponding to the timing of the counter value “0” of the next received data.

  The second clock generation unit 256 sets the second frequency clock (SSCK) for each decoded data corresponding to each received data from “L” to “H” at the timing of the counter value “5” of each received data. To change.

  In the case of FIG. 14, since the next value of the counter value “8” of the first received data is “0” instead of “9”, the second frequency clock (SSCK) “H” of the second decoded data is changed to “0”. The period is shorter than the normal one by one sampling period. Similarly, the output period of the first decoded data corresponding to the “H” output period of the first second frequency clock (SSCK) is shorter than the normal one by one sampling period.

  In the case of FIG. 15, since the counter value “0” of the second received data continues twice, the “L” period of the second second frequency clock (SSCK) for the second decoded data is longer than the normal one. It becomes longer by one sampling period. Similarly, the output period of the second decoded data corresponding to the “L” output period of the second second frequency clock (SSCK) is longer than the normal one by one sampling period. In FIG. 15, when the counter value “0” continues twice, as in the case of the second received data, the first counter value “0” of the received data is adjacently decoded to start output after a specified time delay. At the same timing, the clock (SSCK) falls from “H” to “L” at a data boundary.

  As described above, in this embodiment, after the waveform edge of the first received data is detected, counting is performed with the clock of the first frequency, and when the waveform edge occurs at the bit-by-bit boundary of each received data, When the counter value at the timing of the waveform edge at the boundary is different from the normal value, the counter value is corrected. As a result, the logic inversion timing for judging the logic of the Manchester encoded waveform always falls within the range of the data reproduction window from the counter value “1” to “7” of the received data, and for each bit of each received data. When a waveform edge occurs at the boundary, the start timing of the data reproduction window can be adjusted so that the waveform edge at the bit boundary does not enter the data reproduction window.

  Note that the internal configuration of the reception data processing unit 113 of the front door device 100 and the reception data processing unit 313 of the extension monitor 300 are also the same as the internal configuration of the reception data processing unit 213 of the doorphone master device 200 shown in FIG.

<Flow of synchronization detection processing>
Next, the flow of the synchronization detection process in the doorphone parent device 200 (reception data processing unit 213, connection state detection unit 234) will be described with reference to FIG.

  In step S610, the reception data processing unit 213 receives the pre-demodulation output from the reception driver 211 by the first unique pattern detection unit 251 and the second unique pattern detection unit 252 using the clock of the first clock generation unit 231. Preamble data included in the downlink signal is sampled, and the unique pattern of the preamble data is checked based on the number of clocks in the measurement section that is either between adjacent falling edges or 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 234 checks the sync pattern of the reception data output from the data reproduction unit 233.

  When the sync pattern of the received data matches the sync pattern for the normal connection check (S640: YES), in step S650, the connection state detection unit 234 determines that the two-wire cable is a normal connection, and performs a synchronization detection process. 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 234 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 234 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. 18 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. 19 is a flowchart illustrating 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. 20 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. 21 and 22. In the example of FIG. 21, the door phone master unit 200 (control unit 207 (described as “master unit control unit” in FIG. 21)) 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. 22 is a diagram illustrating an internal configuration of the routing control unit 212. As illustrated in FIG. 22, the routing control unit 212 includes a changeover switch 2121, an OR circuit 2122, and a duty ratio correction unit 2123 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 transmission 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 reception data processing unit 213 in the routing control unit 212, and at the same time, directly transmits the data 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 broadcasting. 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 doorphone master device 200 receives data of the entrance slave device 100 from the DRV 2 (setting pattern P4), the control unit 207 validates the DRV2 reception driver (Rx) and transmits another DRV transmission driver (Tx). ) Is enabled. In this case, the data from the entrance cordless handset 100 is received from the DRV 2, passes through the OR circuit 2122 of the routing control unit 212, and is output to the reception data processing unit 213 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 duty ratio correction unit 2123 and 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.

  When data is transferred to the master unit of another door phone system via DRV1, the duty ratio of the received data is corrected by the duty ratio correction unit 2123.

<Routing control during initial registration>
Next, a specific example of routing control at the time of initial registration of door phone master device 200 according to the present embodiment will be described with reference to FIGS. In the example of FIG. 23, the case where the door phone master unit 200 (the control unit 207 (described as “master unit control unit” in FIG. 23)) 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. 21 are used for transmission of packets from each registration target device to the intercom base unit 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”.

<Detailed description of duty ratio correction processing>
The duty ratio correction unit 2123 stores the median value of the counter value of the data reproduction window. The duty ratio correction unit 2123 then shifts the counter value of the waveform edge for logic determination of the input received data (rising timing or falling timing for logic determination of Manchester encoded received data) from the median value. If so, adjust the waveform inversion of the received data so that it matches the median. As a result, the duty ratio is corrected so as to approach 50%.

  For example, as shown in FIG. 24, the median value of the data reproduction window whose counter value is “1” to “7” is “4”. When the counter value at the timing 521 at which the waveform of the input received data is inverted from “H” to “L” is “2” (FIG. 24A), the duty ratio correction unit 2123 displays the counter value “ The sampling data 522 in the range from “2” to “4” is inverted from “L” to “H”, and the timing 523 at which the waveform of the input received data is inverted from “H” to “L” is the counter value “4”. (FIG. 24B).

  Similarly, when the counter value at the timing 521 is “1”, the duty ratio correction unit 2123 inverts the sampling data 522 in the range from the counter value “1” to “4”, and the counter value at the timing 521 is When it is “3”, the sampling data 522 in the range from the counter value “3” to “4” is inverted, and when the counter value at the timing 521 is “5”, the counter value “4” to “5” When the sampling data 522 in the range up to "6" is inverted and the counter value at the timing 521 is "6", the sampling data 522 in the range from the counter value "4" to "6" is inverted, and the counter at the timing 521 When the value is “7”, the sampling data 522 in the range from the counter value “4” to “7” is inverted.

  When the counter value at timing 521 is “4”, the duty ratio correction unit 2123 passes the input received data as it is.

<Duty ratio correction process flow>
Next, the flow of the duty ratio correction process in the door phone master device 200 (received data decoding unit 255, duty ratio correction unit 2123) will be described with reference to FIG.

  In step S901, the reception data decoding unit 255 detects the counter value of the waveform edge for logical determination of the reception data from the counter value “1” to the counter value “7” when performing the decoding process of the reception data. Then, information indicating the counter value is output to the duty ratio correction unit 2123.

  In step S902, the duty ratio correction unit 2123 compares the counter value output from the reception data decoding unit 255 with the median value of the counter value of the data reproduction window.

  When the counter value deviates from the median value (S903: NO), in step S904, the duty ratio correction unit 2123 adjusts the waveform inversion time of the input received data so as to match the median value. Correct. On the other hand, when the counter value matches the median value (S903: YES), the duty ratio correction unit 2123 passes the input received data as it is. The reception data decoding unit 255 detects the counter value at the time when the waveform of the reception data is inverted and outputs the received data bit output to the duty ratio correction unit 2123 and the duty ratio correction unit 2123 performs the duty ratio correction. Although a known delay occurs between the received data bits, in the present embodiment, when the duty ratio is corrected, the duty ratio correction unit 2123 applies to the received data in which the known delay occurs. The count value of the second counter, which starts counting with exactly the same known delay, matches the bit of each received data with each counter value. It should be noted that the same counter may be used to shift the count value by a known delay to associate each received data with the count value.

<Effects of the present embodiment>
As described above, in the present embodiment, door phone base unit 200 outputs received data received from one of the connected devices to control unit 207 and broadcasts it to other devices. At the time of broadcast transmission, the duty ratio correction unit 2123 performs logic determination when the counter value at the time of inversion of the waveform for logic determination of the Manchester encoded reception data is shifted from the median value of the counter value of the data reproduction window. The duty ratio is corrected by adjusting the waveform reversal position to match the median value. As a result, when receiving data is transferred, it is possible to transfer the data after correcting the deviation of the duty ratio of the received waveform for each bit of the received data before decoding at the transfer source intercom 200. Therefore, the received data can be correctly decoded in the transfer destination device.

  In the present embodiment, a case has been described in which when the duty ratio of the received waveform of the received data is deviated, the data is always transferred with the duty ratio corrected to approach 50%. However, the present invention is not limited to this, and the data may be transferred without correcting the duty ratio as long as the duty ratio of the received waveform of the received data is within a range that can be normally received by the receiving apparatus. For example, if the transmission side device can receive normally if the duty ratio of the data transferred by the transmission side device is in the range of 40% to 60%, the transmission side device has the duty ratio of 40% to 60%. Correction is not performed in the range of. Thereby, since the circuit scale can be reduced, the system can be simplified.

  In this embodiment, the case where the duty ratio of the reception waveform of the Manchester encoded reception data is corrected has been described. However, the present invention is not limited to this, and a waveform edge occurs at the boundary of each bit of the reception data. It can also be applied to correction of the duty ratio of general digital data. For example, as shown in FIG. 26, when the counter value of the waveform edge 531 of the digital data is “7” (FIG. 26A), the doorphone parent device 200 has the counter values “7” to “9”. The sampling data 532 in the range is inverted from “L” to “H”, and the waveform edge 531 of the digital data is made to coincide with the prescribed counter value “9” (FIG. 26B). Thereby, it is possible to correct the duty ratio of general digital data so as to approach 50%.

  In this embodiment, the case where only the waveform edge for logic determination is adjusted in the Manchester encoded reception data has been described. However, the present invention is not limited to this, and the waveform edge at the boundary of each bit is also adjusted. May be. For example, as shown in FIG. 27, when the waveform edge 541 for logic determination is “2” and the waveform edge 542 at the boundary of each bit is “8” (FIG. 27A), the intercom master unit 200 inverts the sampling data 543 in the range from the counter value “2” to “4” from “L” to “H”, and sets the sampling data 544 in the range from the counter value “8” to “9” to “H”. ”To“ L ”, the waveform edge 541 for logic determination is adjusted to match the first specified counter value“ 4 ”, and the waveform edge 542 at the boundary of each bit is adjusted to the second specified value. You may adjust so that it may correspond to counter value "9".

<Variation 1 of synchronous detection processing>
Hereinafter, variation 1 of the present embodiment 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 received data processing unit 213a shown in FIG. 28, the same components as those in the received data processing unit 213 shown in FIG. The reception data processing unit 213a illustrated in FIG. 28 employs a configuration in which a reception data inversion unit 261 is added as compared with the reception data processing unit 213 illustrated in FIG.

  The first unique pattern detection unit 251 and the second unique pattern detection unit 252 store a first specified number (for example, “18” to “22”) of clocks for detecting a unique pattern.

  The first unique pattern detection unit 251 samples the preamble data included in the reception data output from the reception data inversion unit 112 with the clock of the first clock generation unit 131, and between adjacent falling edges that are measurement intervals Count the clocks. The first unique pattern detection unit 251 determines that a unique pattern has been detected when the number of clocks between adjacent falling edges matches one of the first specified numbers. Then, the first unique pattern detection unit 251 outputs a signal indicating that to the enable signal generation unit 253 at a predetermined timing.

  The reception data inversion unit 261 inverts the reception data output from the reception data inversion unit 112 and outputs the inverted reception data to the second unique pattern detection unit 252.

  The second unique pattern detection unit 252 samples the preamble data included in the reception data output from the reception data inversion unit 261 at the same timing as the first unique pattern detection unit 251, and between adjacent falling edges Count the clock. The second unique pattern detection unit 252 determines that a unique pattern has been detected when the number of clocks between adjacent falling edges matches one of the first specified numbers, and generates a signal indicating that effect To the unit 253.

  The unique pattern detection will be described in more detail with reference to FIG. FIG. 29A 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. 29A is obtained by the first unique pattern detection unit 251. The number of clocks to be counted is shown, and (2) in FIG. 29A shows the number of clocks counted by the second unique pattern detection unit 252. FIG. 29B 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. 29B is obtained by the first unique pattern detection unit 251. The number of clocks to be counted is shown, and (2) in FIG. 29B shows the number of clocks counted by the second unique pattern detection unit 252.

  When the two-wire cable is positively connected, as shown in (1) of FIG. 29A, the number of clocks counted in the first unique pattern detection unit 251 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 251 detects the unique pattern 1, the enable signal generation unit 253 causes the enable signal (SSCS) to fall (activate) at a predetermined position Z. On the other hand, as shown in (2) of FIG. 29A, the number of clocks counted in the second unique pattern detection unit 252 is “10” or “15” between any adjacent falling edges, Does not match any of the first specified number. For this reason, the second unique pattern detection unit 252 cannot detect a unique pattern. In this way, when the two-wire cable is positively connected, in the reception data processing unit 213a (the first unique pattern detection unit 251 and the second unique pattern detection unit 252), the unique pattern 1 whose sampling clock number is unique is Only detected.

  When the two-wire cable is reversely connected, the number of clocks counted in the second unique pattern detection unit 252 is between adjacent falling 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 falling edges, and does not match any of the first specified numbers. When the second unique pattern detection unit 252 detects the unique pattern 2, the enable signal generation unit 253 causes the enable signal (SSCS) to fall (activate) at a predetermined position Y. On the other hand, as shown in (1) of FIG. 29B, the number of clocks counted in the first unique pattern detection unit 251 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 251 cannot detect a unique pattern. As described above, when the two-wire cable is reversely connected, the received data processing unit 213a (the first unique pattern detection unit 251 and the second unique pattern detection unit 252) has a unique pattern 2 with a unique sampling clock number. Only detected.

  Note that the received waveform in (2) in FIG. 29B is the same as that in (1) in FIG. 29A, and the number of clocks between falling edges is the first specified number when the polarity is normal. When there is a unique pattern, there is inevitably a unique pattern in which the number of clocks between falling edges is 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.

  Note that the same effect can be obtained even if the interval between adjacent rising edges of the received data is set as a measurement interval. Detection of the unique pattern in this case will be described with reference to FIG. FIG. 30A 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. 30A is obtained by the first unique pattern detection unit 251. The number of clocks to be counted is shown. (2) in FIG. 30A shows the number of clocks counted by the second unique pattern detection unit 252. FIG. 30B 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. 30B is obtained by the first unique pattern detection unit 251. The number of clocks to be counted is shown, and (2) in FIG. 30B shows the number of clocks counted by the second unique pattern detection unit 252.

  When the two-wire cable is positively connected, as shown in (2) of FIG. 30A, the number of clocks counted in the second unique pattern detection unit 252 is “between adjacent rising edges of the unique pattern 1”. 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 252 detects the unique pattern 1, the enable signal generation unit 253 causes the enable signal (SSCS) to fall (activate) at a predetermined position Y. On the other hand, as shown in (1) of FIG. 30A, the number of clocks counted by the first unique pattern detection unit 251 is “10” or “15” between any adjacent rising edges, It does not match any of the specified numbers. For this reason, the first unique pattern detection unit 251 cannot detect a unique pattern. In this way, when the two-wire cable is positively connected, in the reception data processing unit 213a (the first unique pattern detection unit 251 and the second unique pattern detection unit 252), the unique pattern 1 whose sampling clock number is unique is Only detected.

  When the two-wire cable is reversely connected, as shown in (1) of FIG. 30B, the number of clocks counted in the first unique pattern detection unit 251 is “between adjacent rising edges of the unique pattern 2”. 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 first unique pattern detection unit 251 detects the unique pattern 2, the enable signal generation unit 253 causes the enable signal (SSCS) to fall (activate) at a predetermined position Z. On the other hand, as shown in (2) of FIG. 30B, the number of clocks counted in the second unique pattern detection unit 252 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 252 cannot detect a unique pattern. As described above, when the two-wire cable is reversely connected, the received data processing unit 213a (the first unique pattern detection unit 251 and the second unique pattern detection unit 252) has a unique pattern 2 with a unique sampling clock number. Only detected.

  The received waveform in (1) of FIG. 30B is the same as that in (2) of FIG. 30A, and the number of clocks between rising edges is the first specified number when the polarity is normal. When there is a unique pattern, there is inevitably a unique pattern in which the number of clocks between rising edges is 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.

<Variation 2 of synchronization detection processing>
Hereinafter, Variation 2 of the present embodiment 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 received data processing unit 213b shown in FIG. 31, the same components as those in the received data processing unit 213 shown in FIG. The reception data processing unit 213b illustrated in FIG. 31 employs a configuration in which a repeated pattern number detection unit 271 is added as compared with the reception data processing unit 213 illustrated in FIG.

  The repetitive pattern number detection unit 271 includes a second specified 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 271 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 271 starts operation with respect to the first unique pattern detection unit 251 and the second unique pattern detection unit 252. A trigger signal is output to indicate

  The first unique pattern detection unit 251 and the second unique pattern detection unit 252 start to operate after inputting a trigger signal from the repeated pattern number detection unit 271.

<Flow of variation 2 of synchronous detection processing>
Next, a flow of variation 2 of the synchronization detection process will be described with reference to FIG. In the flow shown in FIG. 32, the steps common to the flow shown in FIG. 16 are denoted by the same reference numerals as those in FIG. The flow shown in FIG. 32 adopts a configuration in which steps S601 and S602 are added before step S610 of the flow shown in FIG.

  In step S601, the reception data processing unit 213b 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 271; Counting is performed when the number of clocks between adjacent 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 variation 2, 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 variation 2, the case where the repeated pattern number detection unit 271 is added to the reception data processing unit 213b has been described. However, the present invention is not limited to this, and the first unique pattern detection unit 251 or the second The unique pattern detection unit 252 can realize the function of the repeated pattern number detection unit 271 described above.

  In variation 2, a reception data inversion unit 261 can be added to the reception data processing unit 213b shown in FIG. 31 as in the reception data processing unit 213c shown in FIG.

  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 doorphone master device 200 and the entrance slave device 100 has been described as an example, but the present invention is not limited to this. For example, as other application devices, there are control devices (communication devices) such as business phones (between extension telephones and control devices), home security devices (between surveillance camera devices and indoor monitors, between various sensor nodes and control devices), etc. The same effect can be obtained.

  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, 261, 312 Reception data inversion unit 113, 213, 213a, 213b, 213c, 313 Received data processing unit 114, 214, 314 Identifier storage unit 131, 231, 331 First clock generation unit 132, 232, 332 Packet generation unit 133, 233, 333 Data reproduction unit 134, 23 334 Connection state detection unit 200 Door phone master unit 206, 306 Display unit 212 Routing control unit 2121 Changeover switch 2122 OR circuit 2123 Duty ratio correction unit 235 Identifier setting unit 251 First unique pattern detection unit 252 Second unique pattern detection unit 253 Enable signal generation unit 254 Timing adjustment unit 255 Received data decoding unit 256 Second clock generation unit 271 Repeat pattern number detection unit 300 Additional monitor

Claims (5)

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 first clock generator for outputting a clock having a first frequency corresponding to n times (n is 1 or more) the bit rate of received data;
A second clock generation unit configured to output a clock having a second frequency corresponding to a bit rate of the reception data, which is generated based on the clock having the first frequency;
Decode each bit of the received data using the clock of the second frequency to obtain decoded data, and output a counter value when the waveform of the received data is inverted of the count by the clock of the first frequency A received data decoding unit,
A duty ratio correction unit that corrects the duty ratio of each bit of the second reception data that is branched before being input to the reception data decoding unit and transferred for broadcast, based on the counter value;
A data reproducing unit that reproduces the decoded data using a clock of the second frequency;
A master unit equipped with The duty ratio correction unit
When the counter value at the timing of the waveform edge for logic determination of the received data encoded by Manchester is different from the specified value, by adjusting the waveform inversion position for logic determination to match the specified value, Correct the duty ratio,
The parent device according to claim 1. A timing adjustment unit that adjusts the output timing of the clock of the second frequency by correcting the second counter value when the second counter value at the waveform edge timing of each bit of the received data is different from a normal value. Further comprising
The second clock generator is
Outputting the clock of the second frequency according to the output timing adjusted by the timing adjustment unit;
The master unit according to claim 1 or 2. The received data decoding unit
The received waveform obtained by performing logical inversion of the received waveform corresponding to 1 bit of the received data encoded by Manchester, except for the start point and the end point of the received waveform corresponding to the 1 bit by sampling the clock of the first frequency. Scanning within the period, and decoding the received data corresponding to the logical inversion of the received waveform,
The parent machine according to any one of claims 1 to 3. A communication method of a master unit of a door phone system that is connected to a slave unit via a two-wire cable and transmits and receives packet signals to and from the slave unit by time division duplexing,
Output a clock of the first frequency corresponding to n times (n is 1 or more) the bit rate of the received data,
Outputting a second frequency clock corresponding to the bit rate of the received data, generated based on the first frequency clock;
Decoding each bit of the received data using the clock of the second frequency;
Reproducing the decoded data using the second frequency clock,
The counter value at the time when the waveform of the reception data of the count by the clock of the first frequency is inverted is output,
Branching from the received data before decoding the received data and correcting the duty ratio of each bit of the second received data transferred for broadcast based on the counter value;
Communication method.

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