JP2017224898A - Slave unit, master unit, monitor and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confine deviation of crystal oscillation frequency between apparatus within the allowance of system operation, inexpensively with high accuracy.SOLUTION: A transmission side data time measurement unit 182 measures reference time, i.e., the time occupied by prescribed number of reproduction data outputted from a data reproduction unit 133. A reception side internal time measurement unit 183 measures comparison time by counting measurement clocks outputted from a measurement clock generation unit 181, by a number corresponding to the time occupied by the prescribed number of data. A reception side time difference calculation unit 184 calculates the time difference between the reference time and comparison time. An adjustment value setting unit 185 adjusts oscillation frequency of a crystal oscillation unit 136, so as to reduce deviation of the reference time and comparison time.SELECTED DRAWING: Figure 12

Description

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

  In recent years, in homes and the like, for example, a slave unit with a camera 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 performs digital communication between an entrance cordless handset connected by a two-wire cable and a door phone master set.

  Each device generates a fundamental frequency of digital communication by a crystal oscillator, and detects a synchronization timing (the timing at the beginning of each bit of received data) with a communication partner based on a clock based on the oscillation frequency of the crystal oscillator.

JP 2007-124227 A

  Variations in the crystal oscillation frequency of each device occur due to temperature differences between the doorphone master unit installed indoors and the entrance cordless unit installed outdoors, individual differences of crystal oscillators, aging, and the like. If the deviation of the crystal oscillation frequency between devices exceeds the permissible range of system operation, it may be possible to generate a bit that causes a reception error because synchronization with the clock cannot be achieved. In the prior art, measures for suppressing the deviation of the crystal oscillation frequency between devices within the allowable range of system operation have not been studied.

  An object of the present disclosure is to provide a slave unit of a door phone system, a master unit, a monitor, and a communication method of the door phone system, which can suppress the deviation of the crystal oscillation frequency between devices within an allowable range of system operation with low cost and high accuracy. That is.

  In the slave unit of the present disclosure, the master unit and the slave unit are connected via a two-wire cable, digital communication is performed between the master unit and the slave unit, and the master unit and the slave unit each have an internal crystal oscillation The slave unit of the door phone system that generates a communication clock corresponding to the bit rate of the digital communication generated based on the oscillation frequency of the child, the crystal oscillation unit that outputs a voltage amplitude signal of the oscillation frequency, Using a measurement clock generated based on the oscillation frequency, a first time occupied by a specified number of data transmitted from the parent device based on the communication clock of the parent device, and a communication clock on the child device side A crystal oscillation frequency control unit that adjusts an oscillation frequency of the crystal oscillation unit so as to reduce a time difference from the second time corresponding to the specified number of data counted in step (b).

  In the master unit of the present disclosure, two master units are connected via a two-wire cable, digital communication is performed between the two master units, and each master unit is connected to a slave unit via a two-wire cable. Each of the parent devices performs digital communication with the child device, and communication corresponding to the bit rate of the digital communication generated based on the oscillation frequency of the internal crystal resonator by the parent device and the child device, respectively. The parent device of the door phone system for generating a clock for the communication, the crystal oscillation unit that outputs a voltage amplitude signal of the oscillation frequency, and the measurement clock generated based on the oscillation frequency, the communication of the parent device The time difference between the first time occupied by the prescribed number of data transmitted from the master unit with reference to the clock for use and the second time corresponding to the prescribed number of data counted by the communication clock on the slave unit side is reduced. Yo In comprises a a crystal oscillation frequency control unit for adjusting the oscillation frequency of the crystal oscillator unit.

  In the monitor of the present disclosure, a parent device and a child device are connected via a two-wire cable, digital communication is performed between the parent device and the child device, and the parent device is connected via a separate two-wire cable from the monitor. Communication that is connected, the master unit performs digital communication with the monitor, and the base unit, the slave unit, and the monitor correspond to the bit rate of the digital communication that is generated based on the oscillation frequency of the internal crystal resonator. The monitor of the door phone system for generating a clock for the communication, using a crystal oscillation unit that outputs a voltage amplitude signal of the oscillation frequency and a measurement clock generated based on the oscillation frequency, for communication of the master unit A time between a first time occupied by a prescribed number of data transmitted from the master unit with reference to a clock and a second time corresponding to the prescribed number of data counted by the communication clock on the slave unit side To reduce, to anda crystal frequency control unit for adjusting the oscillation frequency of the crystal oscillator unit.

  The communication method of the present disclosure is a communication method of a door phone system in which a parent device and a child device are connected via a two-wire cable, and digital communication is performed between the parent device and the child device, wherein the parent device includes: Generating a communication clock on the parent side corresponding to the bit rate of the digital communication generated on the basis of the oscillation frequency on the parent side of the internal crystal resonator, and generating the bit rate on the basis of the communication clock on the parent side The transmission data is transmitted to the slave unit via the two-wire cable, and the slave unit generates the transmission data of the digital communication generated based on the slave unit side oscillation frequency of an internal crystal oscillator. Generates a communication clock on the slave unit corresponding to the bit rate, decodes and reproduces the transmission data from the master unit based on the communication clock on the slave unit, and uses the oscillation frequency on the slave unit as a reference The measurement clock for the slave unit The first time occupied by the specified number of transmission data from the master unit using the measurement clock on the slave unit side and the specified number of data counted by the communication clock on the slave unit side The slave unit side oscillation frequency is adjusted so as to reduce the time difference from the second time corresponding to.

  According to the present disclosure, it is possible to suppress the deviation of the oscillation frequency of the crystal oscillator within the allowable range of the system operation with low cost and high accuracy.

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 time difference of the prescribed number of frames by the difference of the crystal oscillation frequency of one embodiment of this indication The block diagram which shows the internal structure of the crystal oscillation frequency control part of the entrance cordless handset of one embodiment of this indication The block diagram which shows the internal structure of the crystal oscillation part of the entrance cordless handset of one embodiment of this indication The flowchart which shows an example of operation | movement of the synchronous detection process which concerns on one embodiment of this indication Sequence diagram until initial registration according to an embodiment of the present disclosure Sequence diagram from standby state to communication state according to an embodiment of the present disclosure The flowchart which shows an example of operation of the entrance cordless handset concerning an embodiment of this indication The flowchart which shows an example of operation of the door phone main unit concerning an embodiment of this indication The figure which shows the specific example of the routing control at the time of normal operation | movement of the door phone main unit which concerns on one embodiment of this indication The figure which shows the internal structure of the routing control part of the door phone main unit which concerns on one embodiment of this indication The figure which shows the specific example of the routing control at the time of the initial registration of the door phone main unit which concerns on one embodiment of this indication

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.
<System overview>
First, an outline of a door phone system according to an embodiment of the present disclosure will be described.

  FIG. 1 is a system configuration diagram showing an example of a configuration of a door phone system according to the present embodiment. The door phone system according to the present embodiment is a system installed in a two-family house in which housing spaces are divided for a parent household and a child household, for example.

  As shown in FIG. 1, the door phone system 1 includes, for example, a first door phone system 1a arranged in a residential space for a parent household, and a second door phone system 1b arranged in a residential space for a child household, for example. And a communication cable 11 for connecting them.

  The first door phone system 1a includes two first entrance cordless handsets 100a-1 and 100a-2, a first door phone master phone 200a, and a first additional monitor 300a. First entrance cordless handset 100a-1, 100a-2 and first additional monitor 300a are connected to first door phone master 200a via communication cables 101a-1, 101a-2, 301a, respectively. . The first door phone system 1a forms a star-type communication network centered on the first door phone parent device 200a by the data transfer function of the first door phone parent device 200a.

  The second door phone system 1b includes two second entrance cordless handsets 100b-1 and 100b-2, a second doorphone master phone 200b, and a second extension monitor 300b. Second entrance cordless handset 100b-1, 100b-2 and second extension monitor 300b are connected to first door phone master set 200b via communication cables 101b-1, 101b-2, 301b, respectively. . The second door phone system 1b forms a star-type communication network centered on the second door phone parent device 200b by the data transfer function of the second door phone parent device 200b.

  The communication cable 11 connects the first doorphone master device 200a and the second doorphone master device 200b. Each of the communication cables 11, 101a-1, 101a-2, 301a, 101b-1, 101b-2, 301b is a two-wire cable made of a pair of copper wires.

  In the following description, since the first doorphone master device 200a and the second doorphone master device 200b have the same configuration, they will be collectively described as “doorphone master device 200” as appropriate. Moreover, since the 1st entrance cordless handset 100a-1, 100a-2 and the 2nd entrance cordless handset 100b-1, 100b-2 have the same structure, it collects and describes as "the entrance cordless handset 100" suitably. Do. Further, since the first extension monitor 300a and the second extension monitor 300b have the same configuration, they will be collectively described as “the extension monitor 300” as appropriate.

  The entrance cordless handset 100 is provided at the entrance of each of the residence space of the parent household and the residence space of the child household. The intercom main unit 200 and the extension monitor 300 are provided in the respective homes of the parent household and child households, and are fixed to a wall or placed on a table or table.

  When a predetermined operation such as an operation of a call button is performed, the entrance cordless handset 100 generates a control signal including a call signal, shoots a video around the entrance, generates video data, and generates audio around the entrance. Acquire and generate audio data. Further, the front door device 100 performs output of sound according to the sound data and control information received from the doorphone master device 200.

  The intercom master device 200 communicates with the entrance slave device 100, receives control signals, video data, and audio data from the entrance slave device 100, and transmits audio data and control information. In addition, door phone parent device 200 communicates with extension monitor 300. Then, intercom master device 200 transfers control signals, video data and audio data (hereinafter referred to as “various child device data” as appropriate) received from entrance slave device 100 to extension monitor 300, and the audio received from extension monitor 300. Data and control information are transferred to the entrance cordless handset 100.

  When receiving the call signal from the entrance cordless handset 100, the doorphone master unit 200 outputs a ringing tone and outputs video and audio around the entrance. Then, when a predetermined operation such as an operation of a response button is performed, the sound around the doorphone master device 200 is acquired to generate sound data, and is transmitted to the front door device 100 together with the control information.

  Further, the doorphone master unit 200 communicates with another doorphone master unit 200 of the doorphone system 1, transfers various slave unit data received from the entrance slave unit 100 to the other doorphone master unit 200, and other doorphone master units. Predetermined processing such as audio / video output and transfer is performed on the various handset data received from 200.

  When the expansion monitor 300 receives a call signal from the doorphone master unit 200, the expansion monitor 300 outputs a ringing tone and outputs video and audio around the entrance. When a predetermined operation such as an operation of a response button is performed, the sound around the expansion monitor 300 is acquired to generate sound data, and is transmitted to the intercom base unit 200 together with the control information.

  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, a connection state detection unit 134, a crystal oscillation frequency control unit 135, and a crystal oscillation unit 136. 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 is n times (n is 1 or more) the bit rate of the reception data with reference to the oscillation frequency of the crystal oscillation unit 136. A corresponding first frequency (for example, 48 MHz (n = 10)) clock (CLK) is generated and output to the received 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). The clock (SSCK) is generated with reference to the oscillation frequency of the crystal oscillation unit 136.

  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 downlink packet output from 113 is reproduced, digital audio data included in the reproduced downlink packet (decoded data) is output to the audio I / F unit 105, and the sync pattern is output to the connection state detection unit 134. In addition, the data reproduction unit 133 outputs the reproduced downlink packet (digital communication frame) to the crystal oscillation frequency control unit 135. 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.

  The crystal oscillation frequency control unit 135 in the control unit 107 occupies the time occupied by the specified number of reproduction data output from the data reproduction unit 133, and the time by counting the internal measurement clock corresponding to the specified number of data. The oscillation frequency of the crystal oscillation unit 136 is controlled so as to reduce the time difference. Details of the configuration of the crystal oscillation frequency control unit 135 will be described later.

  The crystal oscillation unit 136 of the control unit 107 includes a crystal oscillator, and outputs a voltage amplitude signal (frequency signal) of an oscillation frequency to the first clock generation unit 131, the packet generation unit 132, and the crystal oscillation frequency control unit 135. The crystal oscillation unit 136 finely adjusts the oscillation frequency based on the control of the crystal oscillation frequency control unit 135. The details of the configuration of the crystal oscillation unit 136 will be described later.

  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. Details of the configuration of the reception data processing unit 113 will be described later.

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, a crystal oscillation frequency control unit 235, and a crystal oscillation unit 236. 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 and a routing control unit 212, a reception data processing unit 213, an identifier storage unit 214, and a nonvolatile memory 215. . 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 the reception data, and is based on the oscillation frequency of the crystal oscillation unit 236 and has a first frequency corresponding to n times the bit rate of the reception data ( For example, a 48 MHz (n = 10)) clock (CLK) is generated and output to the reception data processing unit 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). The clock (SSCK) is generated based on the oscillation frequency of the crystal oscillation unit 236.

  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.

  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 uplink packet output from 213 is reproduced, the digital audio data included in the reproduced uplink packet (decoded data) is output to the audio I / F unit 205, the digital video data is output to the display unit 206, and the sync pattern is set. The data is output to the connection state detection unit 234. In addition, the data reproduction unit 233 outputs the reproduced downlink packet (digital communication frame) to the crystal oscillation frequency control unit 235.

  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 crystal oscillation frequency control unit 235 of the control unit 207 includes a time occupied by a specified number of reproduction data output from the data reproduction unit 233, and a time by counting an internal measurement clock corresponding to the specified number of data. The oscillation frequency of the crystal oscillating unit 236 is controlled so as to reduce the time difference. The crystal oscillation frequency control unit 235 turns on / off the control operation for the crystal oscillation unit 236 by an enable signal from the reception data processing unit 213. Specifically, the crystal oscillation frequency control unit 235 does not adjust the oscillation frequency of the crystal oscillation unit 236 when the doorphone main unit 200 is a master base unit that performs slot management. On the other hand, the crystal oscillation frequency control unit 235 adjusts the oscillation frequency of the crystal oscillation unit 236 when the intercom base unit 200 is a slave base unit that does not perform slot management.

  The crystal oscillation unit 236 of the control unit 207 includes a crystal oscillator, and outputs a voltage amplitude signal (frequency signal) of the oscillation frequency to the first clock generation unit 231, the packet generation unit 232, and the crystal oscillation frequency control unit 235. The crystal oscillation unit 236 finely adjusts the oscillation frequency based on the control of the crystal oscillation frequency control unit 235.

  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 unit 100 and output from the reception driver 211-i to the reception data processing unit 213 when addressed to the intercom master unit 200, and to the extension monitor 300. Is output to the corresponding transmission driver 210-i. In addition, the routing control unit 212 outputs the downlink signal output from the transmission data processing unit 208 and addressed to the entrance slave device 100 to the corresponding transmission driver 210-i. In addition, the routing control unit 212 outputs the uplink signal addressed to the entrance slave device 100 transmitted from the extension monitor 300 and output from the reception driver 211-i to the corresponding transmission driver 210-i. The routing control unit 212 controls routing (valid / invalid of communication routes). A specific example of routing control performed by the routing control unit 212 will be described later.

  The 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. The received data processing unit 213 outputs an enable signal (SSCS) for permitting the data reproduction operation to the data reproduction unit 233 and the crystal oscillation frequency control unit 235 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 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).

  The nonvolatile memory 215 holds an initial value of a register of the crystal oscillation unit 236 and the like.

<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, a connection state detection unit 334, a crystal oscillation frequency control unit 335, and a crystal oscillation unit 336. 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 the reception data, and uses a first frequency (corresponding to n times the bit rate of the reception data with reference to the oscillation frequency of the crystal oscillation unit 336). For example, a 48 MHz (n = 10)) clock (CLK) is generated and output to the reception 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). The clock (SSCK) is generated based on the oscillation frequency of the crystal oscillation unit 336.

  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 downlink packet output from 313 is reproduced, the digital video data included in the reproduced downlink packet (decoded data) is output to the display unit 306, the digital audio data is output to the audio I / F unit 305, and the sync pattern is set. The data is output to the connection state detection unit 334. The data reproducing unit 333 outputs the reproduced downlink packet (digital communication frame) to the crystal oscillation frequency control unit 335. 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.

  The crystal oscillation frequency control unit 335 of the control unit 307 includes a time occupied by a specified number of reproduction data output from the data reproduction unit 333 and a time by counting an internal measurement clock corresponding to the specified number of data. The oscillation frequency of the crystal oscillation unit 336 is controlled so as to reduce the time difference.

  The crystal oscillation unit 336 of the control unit 307 has a crystal oscillator and outputs a voltage amplitude signal (frequency signal) of the oscillation frequency to the first clock generation unit 331, the packet generation unit 332, and the crystal oscillation frequency control unit 335. The crystal oscillation unit 336 finely adjusts the oscillation frequency based on the control of the crystal oscillation frequency control unit 335.

  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, details of the internal configuration of the reception data processing unit 113 of the front door device 100 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 illustrates a case where the first clock generation unit 131 generates a 48 MHz clock (CLK) and the second clock generation unit 156 generates a 4.8 MHz clock (SSCK).

  As shown in FIG. 9, the reception data processing unit 113 includes a first unique pattern detection unit 151, a second unique pattern detection unit 152, an enable signal generation unit 153, a timing adjustment unit 154, a reception data decoding unit 155, and A two-clock generation unit 156 is included.

  The reception data output from the reception data inversion unit 112 is input to the first unique pattern detection unit 151, the second unique pattern detection unit 152, the timing adjustment unit 154, and the reception data decoding unit 155. The clock (CLK) of the first clock generation unit 131 is input to the first unique pattern detection unit 151, the second unique pattern detection unit 152, the timing adjustment unit 154, the reception data decoding unit 155, and the second clock generation unit 156. Is done.

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

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

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

  When the enable signal generation unit 153 receives a signal indicating that a unique pattern has been detected from either the first unique pattern detection unit 151 or the second unique pattern detection unit 152 (timing 510 in FIG. 10), data An enable signal for permitting the reproduction operation is output to the timing adjustment unit 154 and the data reproduction unit 133 (in the example of FIG. 10, the enable signal SSCS is lowered to be an L (Low) signal (set to active)).

  The timing adjustment unit 154 includes a timing generation counter therein, and when an enable signal is input from the enable signal generation unit 153, 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 154 repeatedly counts “0” to “9” by the timing generation counter with the clock of the first frequency, and the timing of the waveform edge of each received data Observe the counter value at. When the counter value is different from the normal value, the timing adjustment unit 154 corrects the counter value and outputs the corrected counter value to the reception data decoding unit 155 and the second clock generation unit 156. 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.

  The reception data decoding unit 155 receives the counter value from the timing adjustment unit 154, scans and detects a logical inversion of the waveform for one bit of reception data in 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 155 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. The decoded data of the first received data is output from the received data decoding unit 155 with a certain time delay at approximately the same time as the time when the second received data is input to the received data decoding unit 155. Details of the received data decoding process performed by the received data decoding unit 155 will be described later.

  The second clock generation unit 156 receives the counter value (“0” to “9”) from the timing adjustment unit 154, and at the counter value “0” (timing 512 in FIG. 10) of the second received data, Output ("L" in FIG. 10) is started, and 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. The SSCK logic at the boundary between the first decoded data and the second decoded data is inverted from “H” to “L” with the counter value “0” of the second received data. Thereafter, the second clock generation unit 156 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 156 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”.

  The internal configuration of the reception data processing unit 213 of the door phone main unit 200 and the internal configuration of the reception data processing unit 313 of the extension monitor 300 are the same as the internal configuration of the reception data processing unit 113 of the front door device 100.

<Requirements for crystal oscillation frequency>
Next, requirements for the crystal oscillation frequency of the present embodiment will be described with reference to FIG.

  When the time slot of the data generated by sampling with the clock generated with reference to the crystal oscillation frequency of the transmitting device is sampled with the clock generated with reference to the crystal oscillation frequency of the receiving device, this embodiment Since this system is a system that resynchronizes with the first bit of the sync pattern in the time slot, the user after 1552 bits (= 2 + 32 + 160) x 8) from the first bit of the sync pattern in the same time slot In the data of the last bit of data, the deviation of the clock on the reception side with respect to the clock on the transmission side becomes the maximum. In this system, resynchronization is performed with the first bit of the sync pattern in the next time slot.

  Here, as a system requirement, the allowable range of clock deviation when sampling 1552 bits of data in the time slot is 1/5 (1/10 before and after) of 1 bit data length, that is, ± 64 ppm (= 1) / 1552 x 1/5 x 1/2). If the transmitting side clock is used as a standard, the receiving side device can decode the received data if the receiving side crystal oscillation frequency is adjusted so that the deviation of the receiving side clock is always within ± 64 ppm. .

  Therefore, in the present embodiment, as shown in FIG. 11, a time difference 603 between the transmission side data time 601 and the reception side measurement time 602 is detected with a specified number of data (for example, the number of data for 100 frames), The crystal oscillation frequency on the receiving side is adjusted according to the time difference. The transmission-side data time 601 is a time occupied by a prescribed number of transmission data sampled with a communication clock generated based on the crystal oscillation frequency of the transmission-side device. The measurement time 602 on the reception side is a time corresponding to a specified number of data counted with a communication clock generated based on the crystal oscillation frequency of the device on the reception side.

  If one time slot or one frame (24 time slots) is used to detect the time difference between the transmission side data time and the reception side measurement time, the difference accumulation is small and the time difference is short. A high-speed clock is required.

  In the present embodiment, the minimum range of the adjustment width is determined in advance according to system requirements, for example, MAX ± 5 ppm. The frequency of the measurement clock for detecting the time difference is determined by the minimum range of the adjustment width.

<Internal configuration of crystal oscillation frequency controller>
Next, the details of the internal configuration of the crystal oscillation frequency control unit 135 of the entrance cordless handset 100 will be described with reference to FIG. As shown in FIG. 12, the crystal oscillation frequency control unit 135 includes a measurement clock generation unit 181, a transmission side data time measurement unit 182, a reception side internal time measurement unit 183, a reception side time difference calculation unit 184, and an adjustment value setting unit 185. Have

  The measurement clock generation unit 181 generates a measurement clock having a frequency (for example, 48 MHz) based on the minimum range of the adjustment width based on the crystal oscillation frequency of the crystal oscillation unit 136, and receives the reception-side internal time measurement unit 183 and the transmission. The measurement clock is continuously output to the side data time measurement unit 182. Here, the frequencies of the measurement clock and the communication clock are both known values generated based on the crystal oscillation frequency of the receiving device, and the frequency of the measurement clock is equal to the frequency of the communication clock. May be.

  The transmission-side data time measuring unit 182 occupies the time (the time from the count start point to the count end point of the received data) occupied by the specified number of reproduction data output from the data reproduction unit 133 (hereinafter referred to as “reference time”) ). This reference time is the time occupied by the specified number of transmission data sampled with the communication clock generated based on the oscillation frequency of the internal crystal oscillation unit 236 in the doorphone master unit 200 which is the transmission side device (see FIG. 11 601).

  The reception-side internal time measurement unit 183 converts the time corresponding to the specified number of data counted by the communication clock into the count number of the measurement clock, and counts the measurement clock output from the measurement clock generation unit 181. A number corresponding to the specified number of data is counted from the start point, and a time (602 in FIG. 11) from the start to the end of counting of the measurement clock (hereinafter referred to as “comparison time”) is measured.

  Note that the count start point in the transmission side data time measurement unit 182 and the reception side internal time measurement unit 183 is not particularly limited. For example, after the unique pattern of the preamble of the first time slot in the first frame is detected, the SSCS is “ A point (510 in FIG. 10) that falls from “H” to “L” may be used. In this case, the count end point in the transmission side data time measuring unit 182 is that the SSCS of the first time slot in the 101st frame falls from “H” to “L” if the specified number is 100. It becomes a point. Further, the edge (511 in FIG. 10) between the preamble and the sync pattern may be used as the count start point and the count end point. Here, the point at which SSCS output from the reception data processing unit 113 and input to the crystal oscillation frequency control unit 135 via the data reproduction unit 133 falls from “H” to “L” is defined as the transmission side data. When the measurement start point and the end point are used, the period from the SSCS trigger at the count start point to the SSCS trigger at the count end point is measured by the measurement clock generated by the measurement clock generation unit 181.

  The reception side time difference calculation unit 184 calculates a difference (603 in FIG. 11) between the reference time measured by the transmission side data time measurement unit 182 and the comparison time measured by the reception side internal time measurement unit 183.

  In order to reduce the difference between the reference time and the comparison time, the adjustment value setting unit 185 uses a known capacitance value corresponding to the time difference calculated by the reception-side time difference calculation unit 184 to register 199 of the crystal oscillation unit 136 (see FIG. 13). ) And the oscillation frequency of the crystal oscillation unit 136 is adjusted. Note that when the time difference calculated by the reception-side time difference measurement unit 184 is equal to or less than a predetermined threshold, the adjustment value setting unit 185 may stop adjusting the oscillation frequency. The threshold value may have hysteresis.

  In the present embodiment, the above-described crystal oscillation frequency adjustment operation can be performed in the background in parallel with the reception data processing during the normal operation. Accordingly, it is not necessary to set a time for adjustment, and high-precision digital communication can be performed as long as it is within a variation range of initial adjustment in which a bit error of received data does not occur in a normal reception operation.

  In this embodiment, instead of the measurement clock generated by the measurement clock generation unit 181, the clock generated by the first clock generation unit 131 may be used as the measurement clock.

  Further, the internal configuration of the crystal oscillation frequency control unit 235 of the door phone main unit 200 and the internal configuration of the crystal oscillation frequency control unit 335 of the extension monitor 300 are the same as the internal configuration of the crystal oscillation frequency control unit 135 of the front door device 100. .

  However, in the door phone master unit 200 of the two-door door phone system, the control operation of the crystal oscillation frequency control unit 235 is turned on / off by the enable signal. When the door phone parent device 200 is a master parent device that performs slot management, since the oscillation frequency of the crystal oscillation unit 236 is not adjusted, the operation of the crystal oscillation frequency control unit 235 is turned off such as maintaining the register value as it is. If the slave base unit does not perform slot management, the operation of the crystal oscillation frequency control unit 235 is turned on. Also, if the master base unit becomes unable to communicate due to reasons such as the power breaker being disconnected and the slave base unit detects that there is no response from the master base unit for a specified time or a specified number of times, it can operate. The slave base unit starts operating as the master base unit. In this case, the crystal oscillation frequency of the new master base unit becomes a reference for adjustment, and the new master base unit turns off the operation of the crystal oscillation frequency control unit 235.

  In the case of a single door phone system that is not connected to other door phone systems (when the door phone systems 1a and 1b are not connected by the communication cable 11 in FIG. 1), the door phone parent device 200 always turns off the operation of the crystal oscillation frequency control unit 235. Alternatively, the crystal oscillation frequency control unit 235 is not provided.

  In addition, when the doorphone parent device 200 having the reference crystal oscillation frequency is restarted by reset, the doorphone parent device 200 sets the register value to the initial value held in the nonvolatile memory 215, and before the normal operation. After completing the adjustment of the crystal oscillation frequency of all the connected devices, shift to normal operation.

<Internal configuration of crystal oscillator>
Next, the details of the internal configuration of the crystal oscillation unit 136 of the entrance cordless handset 100 will be described with reference to FIG. As shown in FIG. 13, the crystal oscillation unit 136 includes a crystal oscillator 190 (vibration frequency X1), an inverter 191, a feedback resistor 192 (resistance value Rf), a damping resistor 193 (resistance value Rd), a buffer 194, and an input capacitor 195. A configuration in which an input capacitor 197 (capacitance value C1), an output capacitor 198 (capacitance value C4), and a register 199 are added to a general CMOS inverter crystal oscillation circuit composed of (capacitance value C2) and output capacitance 196 (capacitance value C3). Take.

  The capacitance value C1 of the input capacitor 197 and the capacitance value C4 of the output capacitor 198 are set in advance so as to be a prescribed value corresponding to the initial value of the register 199.

  When a new value is set in the register 199 by the crystal oscillation frequency control unit 135 (adjustment value setting unit 185), the capacitance value C1 of the input capacitor 197 or the capacitance value C4 of the output capacitor 198 is adjusted according to this value. The As a result, the oscillation frequency of the crystal oscillation unit 136 is finely adjusted to match the crystal oscillation frequency of the doorphone master device 200 on the transmission side. A voltage amplitude signal (frequency signal) of an oscillation frequency that is an output signal of the crystal oscillation unit 136 is output to the crystal oscillation frequency control unit 135 and the first clock generation unit 131.

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

  In step S <b> 610, the reception data processing unit 113 uses the first unique pattern detection unit 151 and the second unique pattern detection unit 152 to generate a pre-demodulation signal output from the reception driver 111 using the clock of the first clock generation unit 131. 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 134 checks the sync pattern of the reception data output from the data reproduction unit 133.

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

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

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

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

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

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

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

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

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

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

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

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

<Sequence from standby state to communication state>
Next, a sequence from the standby state (during asynchronous communication) to the communication state according to the present embodiment will be described with reference to FIG. In addition, in FIG. 16, the sequence in case the front cordless handset 100-1,100-2 and the expansion monitor 300 are connected with the door phone main unit 200 is shown.

  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. 17 is a flowchart showing an example of the operation of the front door device 100.

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

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

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

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

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

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

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

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

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

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

<Operation of doorphone master unit>
FIG. 18 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 routing control during normal operation of door phone parent device 200 according to the present embodiment will be described with reference to FIGS. 19 and 20. In the example of FIG. 19, the intercom base unit 200 (control unit 207 (described as “base unit control unit” in FIG. 19)) 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. 20 is a diagram illustrating an internal configuration of the routing control unit 212. As illustrated in FIG. 20, the routing control unit 212 includes a changeover switch 2121 and an OR circuit 2122 inside.

  The setting pattern P1 indicates routing (valid / invalid of communication route) in a standby state in which the intercom base unit 200 is not transmitting / receiving data to / from any device. In setting pattern P1, door phone base unit 200 is in a reception mode (a mode in which only reception is performed without transmission), and control unit 207 is in a 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 intercom 200 receives data from the DRV 2 from the DRV 2, the control unit 207 enables the DRV 2 reception driver (Rx) and enables other DRV transmission drivers (Tx). . In this case, the data from the entrance 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 changeover switch 2121 and is broadcast to each connected device. At that time, only the reception driver (Rx) is valid for DRV2, and the transmission driver (Tx) is invalid. Therefore, the data passing through the OR circuit 2122 is not broadcast from DRV2. At this time, even if data is transmitted from another device to the intercom base unit 200, it cannot be received by the DRVs 1, 3, 4, 5 and the base unit 200 discards the data.

<Routing control during initial registration>
Next, a specific example of the routing control at the time of initial registration of the doorphone parent device 200 according to the present embodiment will be described with reference to FIGS. In the example of FIG. 21, a case where the doorphone master unit 200 (the control unit 207 (described as “master unit control unit” in FIG. 21)) 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. 19 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”.

<Effects of the present embodiment>
As described above, in this embodiment, the receiving-side device calculates the difference between the clock based on the oscillation frequency of the internal crystal oscillation unit and the clock based on the crystal oscillation frequency of the transmitting-side device. By adjusting the oscillation frequency of the internal crystal oscillation unit so as to reduce the deviation, the deviation of the crystal oscillation frequency between devices can be suppressed within the allowable range of system operation.

  In this embodiment, even if an inexpensive crystal oscillator is used by detecting a time difference between a transmission side and a reception side in a prescribed number (for example, 100 frames), the transmission side and the reception side Can be calculated with high accuracy.

  In this embodiment, the time-division duplex digital communication has been described as an example, but the present invention is not limited to this, and by setting the oscillation frequency of the crystal oscillation unit to satisfy each system requirement, It can be applied to other digital communications. 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, 312 Reception data inversion unit 113, 213, 313 Reception 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, 234, 334 Connection state detection unit 135, 235 335 Crystal oscillation frequency control unit 136, 236, 336 Crystal oscillation unit 151 First unique pattern detection unit 152 Second unique pattern detection unit 153 Enable signal generation unit 154 Timing adjustment unit 155 Received data decoding unit 156 Second clock generation Unit 181 Measurement clock generation unit 182 Transmission side data time measurement unit 183 Reception side internal time measurement unit 184 Reception side time difference calculation unit 185 Adjustment value setting unit 190 Crystal oscillator 191 Inverter 192 Feedback resistor 193 Damping resistor 194 Buffer 195, 197 Input Capacity 196, 198 Output capacity 199 Register 200 Door phone master unit 206, 306 Display unit 212 Routing control unit 215 Non-volatile memory 300 Additional monitor

Claims (22)

The master unit and the slave unit are connected via a two-wire cable, and digital communication is performed between the master unit and the slave unit. The master unit and the slave unit are respectively based on the oscillation frequency of the internal crystal oscillator. The slave unit of the door phone system that generates a communication clock corresponding to the bit rate of the generated digital communication,
A crystal oscillation unit that outputs a voltage amplitude signal of the oscillation frequency;
Using a measurement clock generated based on the oscillation frequency, a first time occupied by a prescribed number of data transmitted from the parent device based on the communication clock of the parent device, and for communication on the child device side A crystal oscillation frequency control unit that adjusts an oscillation frequency of the crystal oscillation unit so as to reduce a time difference from a second time corresponding to the specified number of data counted by a clock;
A handset comprising The crystal oscillation frequency controller is
A transmission-side data time measurement unit that measures the first time from a count start point;
A receiving-side internal time measuring unit that measures the second time from the count start point;
A receiving side time difference calculating unit for calculating a time difference between the first time and the second time;
An adjustment value setting unit for adjusting an oscillation frequency of the crystal oscillation unit by setting a known capacitance value corresponding to the time difference in the crystal oscillation unit;
Having
The subunit | mobile_unit of Claim 1. A first clock generation unit that outputs a clock having a first frequency corresponding to n times (n is 1 or more) of a bit rate of received data with reference to the oscillation frequency;
A second clock generation unit configured to output a communication 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;
A received data decoding unit that obtains decoded data by decoding each bit of the received data using the communication clock of the second frequency;
A data reproduction unit that reproduces the decoded data using the second frequency communication clock to obtain reproduction data;
Comprising
The subunit | mobile_unit of Claim 1 or 2. The crystal oscillation frequency control unit performs processing for adjusting the oscillation frequency of the crystal oscillation unit in the background in parallel with the processing of the reception data decoding unit and the data reproduction unit.
The subunit | mobile_unit of Claim 3. The crystal oscillation frequency controller is
A clock generation unit that generates a measurement clock having a frequency determined by the minimum range of the adjustment width;
The subunit | mobile_unit as described in any one of Claim 1 to 4. Using the first frequency clock as the measurement clock,
The subunit | mobile_unit of Claim 3 or 4. Two master units are connected via a two-wire cable, digital communication is performed between the two master units, and each master unit is connected to a slave unit via a separate two-wire cable. A door phone system in which a machine performs digital communication with the slave unit, and the master unit and the slave unit each generate a communication clock corresponding to the bit rate of the digital communication generated based on the oscillation frequency of an internal crystal oscillator Said master unit,
A crystal oscillation unit that outputs a voltage amplitude signal of the oscillation frequency;
Using a measurement clock generated based on the oscillation frequency, a first time occupied by a prescribed number of data transmitted from the parent device based on the communication clock of the parent device, and for communication on the child device side A crystal oscillation frequency control unit that adjusts an oscillation frequency of the crystal oscillation unit so as to reduce a time difference from a second time corresponding to the specified number of data counted by a clock;
A master unit equipped with The crystal oscillation frequency controller is
A transmission-side data time measurement unit that measures the first time from a count start point;
A receiving-side internal time measuring unit that measures the second time from the count start point;
A receiving side time difference calculating unit for calculating a time difference between the first time and the second time;
An adjustment value setting unit for adjusting an oscillation frequency of the crystal oscillation unit by setting a known capacitance value corresponding to the time difference in the crystal oscillation unit;
Having
The parent device according to claim 7. A first clock generation unit that outputs a clock having a first frequency corresponding to n times (n is 1 or more) of a bit rate of received data with reference to the oscillation frequency;
A second clock generation unit configured to output a communication 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;
A received data decoding unit that obtains decoded data by decoding each bit of the received data using the communication clock of the second frequency;
A data reproduction unit that reproduces the decoded data using the second frequency communication clock to obtain reproduction data;
Comprising
The master unit according to claim 7 or 8. The crystal oscillation frequency control unit performs processing for adjusting the oscillation frequency of the crystal oscillation unit in the background in parallel with the processing of the reception data decoding unit and the data reproduction unit.
The master unit according to claim 9. The crystal oscillation frequency controller is
A clock generation unit that generates a measurement clock having a frequency determined by the minimum range of the adjustment width;
The master unit according to any one of claims 7 to 10. Using the first frequency clock as the measurement clock,
The parent device according to claim 9 or 10. The crystal oscillation frequency controller is
When the own device is a master base unit that performs slot management, the process of adjusting the oscillation frequency of the crystal oscillation unit is performed. When the own unit is a slave base unit that does not perform slot management, the crystal oscillation unit Do not adjust the oscillation frequency.
The parent device according to any one of claims 7 to 12. The crystal oscillation frequency controller is
When it is detected that there is no response from the master base unit at a specified time or a specified number of times when the own unit is a slave base unit, a process for adjusting the oscillation frequency of the crystal oscillation unit as the master base unit is performed.
The parent device according to claim 13. The crystal oscillation frequency controller is
When restarting by reset, call the initial value of the oscillation frequency of the crystal oscillation unit held in the nonvolatile memory and complete the process of adjusting the oscillation frequency of the crystal oscillation unit of all connected devices before normal operation And then move to normal operation,
The parent machine according to any one of claims 7 to 14. A master unit and a slave unit are connected via a two-wire cable, digital communication is performed between the master unit and the slave unit, and the master unit is connected via a separate two-wire cable to the monitor. Doorphone which performs digital communication with the monitor and generates a communication clock corresponding to the bit rate of the digital communication generated by the master unit, the slave unit, and the monitor based on the oscillation frequency of the internal crystal resonator Said monitor of the system,
A crystal oscillation unit that outputs a voltage amplitude signal of the oscillation frequency;
Using a measurement clock generated based on the oscillation frequency, a first time occupied by a prescribed number of data transmitted from the parent device based on the communication clock of the parent device, and for communication on the child device side A crystal oscillation frequency control unit that adjusts an oscillation frequency of the crystal oscillation unit so as to reduce a time difference from a second time corresponding to the specified number of data counted by a clock;
A monitor comprising: The crystal oscillation frequency controller is
A transmission-side data time measurement unit that measures the first time from a count start point;
A receiving-side internal time measuring unit that measures the second time from the count start point;
A receiving side time difference calculating unit for calculating a time difference between the first time and the second time;
An adjustment value setting unit for adjusting an oscillation frequency of the crystal oscillation unit by setting a known capacitance value corresponding to the time difference in the crystal oscillation unit;
Having
The monitor according to claim 16. A first clock generation unit that outputs a clock having a first frequency corresponding to n times (n is 1 or more) of a bit rate of received data with reference to the oscillation frequency;
A second clock generation unit configured to output a communication 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;
A received data decoding unit that obtains decoded data by decoding each bit of the received data using the communication clock of the second frequency;
A data reproduction unit that reproduces the decoded data using the second frequency communication clock to obtain reproduction data;
Comprising
The monitor according to claim 16 or 17. The crystal oscillation frequency control unit performs processing for adjusting the oscillation frequency of the crystal oscillation unit in the background in parallel with the processing of the reception data decoding unit and the data reproduction unit.
The monitor according to claim 18. The crystal oscillation frequency controller is
A clock generation unit that generates a measurement clock having a frequency determined by the minimum range of the adjustment width;
The monitor according to any one of claims 16 to 19. Using the first frequency clock as the measurement clock,
The monitor according to claim 18 or 19. A communication method of a door phone system in which a parent device and a child device are connected via a two-wire cable, and digital communication is performed between the parent device and the child device,
The master unit is
Generate a communication clock on the base side corresponding to the bit rate of the digital communication generated based on the base side oscillation frequency of the internal crystal oscillator,
Generate transmission data of the bit rate based on the communication clock on the base unit side,
Transmitting the transmission data to the slave unit via the two-wire cable;
The slave is
Generate a communication clock on the handset side corresponding to the bit rate of the digital communication generated based on the handset side oscillation frequency of the internal crystal oscillator,
Decode and reproduce the transmission data from the base unit based on the communication clock on the slave side,
Generate a measurement clock on the slave side based on the oscillation frequency on the slave side,
Using the measurement clock on the slave unit side, this corresponds to the first time occupied by the prescribed number of transmission data from the master unit and the prescribed number of data counted by the communication clock on the slave unit side Adjusting the handset side oscillation frequency so as to reduce the time difference from the second time,
Communication method.

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