KR930006548B1 - Method of receiving multichannel r2mfc/cct combinations in use digital signal processor - Google Patents

Abstract

The method effectively receives and detects both R2MFC and CCT signals by using digital signal processor. It is composed of the stages of: initializing the content of the data necessary for program execution; judging (14) the order of the channel to be processed by a digital signal processor (5); detecting the code information of corresponding signal; and repeating the stages from the 2nd stage.

Description

Multichannel R2MFC / CCT Receiving Method Using Digital Signal Processor

1 is a block diagram of an R2MFC / CCT combined receiver using a digital signal processor.

2 is an information area display diagram of an input / output memory in an R2MFC / CCT receiving device.

3 is a view showing a reception area of an input / output memory in an R2MFC / CCT receiving device.

4 is a program flow diagram illustrating a multi-channel R2MFC / CCT combined reception method in a digital signal processor of the present invention.

The present invention relates to a combined reception method of an R2 Multi-Frequency Compelled (R2MFC) signal and a Continuity Check Tone (CCT) signal used for connection to a call during a call processing process in an electronic exchange with the same device.

Digital signal processors (DSPs), which are capable of high-speed operation due to the rapid development of digital signal processing technology and semiconductor technology along with the digitalization of the exchange of communication networks, have been widely applied in the communication and exchange fields. If you implement various signal service devices such as R2MFC receiver, CCT receiver, etc. to which signal processing technology is applied in exchange, as digital signal processor, you can apply multiplexing concept, reduce volume, improve reliability, reduce price, maintain There are advantages such as ease of maintenance. In addition, these signaling service functions are commonly provided to the trunk line via a time switch device. However, as the signaling service devices are distributed by functions and their respective devices are used, the signaling service autonomous area in the exchange increases and reliability is lowered and maintained. Not only is it difficult to repair and operate, but it also has many disadvantages in productivity and economics.

Therefore, the present invention configures a combined receiver of R2MFC and CCT signals in a switchboard using a digital signal processor, and more efficiently receives a signal by using an R2MFC / CCT combined receiver program performed by a digital signal processor in the receiver. An object of the present invention is to provide a multi-channel R2MFC / CCT combined receiving method using a digital signal processor capable of detecting.

The present invention provides a digital signal processor, an EP ROM connected to the digital signal processor, a channel multiplexing circuit, an input / output memory, a monitor, a reset circuit and a local oscillator, a microcontroller connected to the input / output memory and a monitor, and the channel multiplexing. A R2MFC / CCT combined receiver having a timing control circuit connected to a circuit and a monitor, comprising: a first step of initializing various data contents required for a multi-channel R2MFC / CCT combined reception program to be executed in the digital signal processor; If the PCM data is input, the function mode information sent from the microcontroller is read from the input / output memory, and the digital signal processor reads out the data of the channel to be processed by the digital signal processor. The second judging sequence In a third step of converting the PCM data input to the digital signal processor after the second step into linear data by a memory look-up table method, multiplying a window function with respect to the transformed linear data after the third step and multiplying the DFT. A fourth step of determining whether a function mode to be processed in a channel to be performed is an R2MFC function or a CCT function after calculating a power spectrum for each R2MFC and CCT signal frequency component by a method; If it is determined in the fourth step that the R2MFC function is used, the corresponding signal code information is detected by applying the relevant parameter for detecting and determining as an R2MFC signal code using the DFT calculation result, and if the CCT function is determined, the DFT calculation result is used. A fifth step of detecting corresponding signal code information by applying relevant parameters for detecting and determining as a CCT signal code, And a sixth step of re-determining the sequence number of the channel to be processed by the digital signal processor after the fifth step, processing the data after performing the function of the corresponding channel, and repeating again from the second step. do.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

Among the signaling service functions required for the connection from the electronic exchange to the call, the R2MFC signal transmission / reception function is used for smooth information exchange between electronic switching stations using channel associated signaling. Likewise, the signal code information is divided into 6C ₂ combinations of forward and backward frequencies in which six frequencies in the voice band (300 to 3,400 Hz) are formed in the high frequency band and the low frequency band, respectively. It is used to represent the front and rear signal code information, respectively, and transmit each other in a compulsory manner in order to improve the transmission reliability of the signal. The cycle time until the completion of transmission of one signal code information is It is specified as 120ms to prevent delay of signal transmission. Table 1 shows the main reception standard table for the R2MFC signal, which is received and detected as signal code information only when the R2MFC signal received by the R2MFC / CCT receiving device meets the prescribed requirements shown in FIG. When the operating frequency range is 'within reference frequency ± 10Hz' and the received power level for each component frequency of the combined signal code information is -5 to -35BmO, it should not be regarded as signal code information when it is below -42dBmO. In addition, the difference in the received power level between the constituent frequencies of the combined signal codes should have a value between 5 and 7 dB, and should be detected at 40 ms or less when the signal code information continues continuously, and the signal code information is 7 ms or less during the continuous operation. It should be ignored when a signal interrupt occurs, which is a phenomenon in which the signal duration is interrupted.

TABLE 1

The CCT signal transmission and reception function is necessary to confirm whether the communication channel between the switching stations using common channel signaling is normal, and the single tone in the sound band as shown in FIG. 2 before the trunk line communication channel is connected. Two types of test tones of 1,780 Hz and 2,000 Hz, which are the frequencies of the tone, are transmitted and received with the counterpart switching center. This continuity test differs depending on the type of test sound used and the test method depending on whether the path is two or four wire type. Table 2 shows the main reception standard table for CCT signals. When the CCT signal received by the CCT receiver meets the prescribed requirements shown in Table 2, it is detected as signal information. Within the reference frequency ± 10 Hz ', and the operating level range of the received signal frequency should be between (-3 + n) and (-6 + n) dBmO (where n is the relative power level at the receiver input). If the signal duration is maintained for 30 to 60 ms, it is received as signal information. However, when the received frequency is 'reference frequency ± 200Hz or more' or the power level of the received frequency is '-22 + n dBmO or less' is not regarded as signal information.

TABLE 2

* n: Relative power level at receiver input.

FIG. 1 is a block diagram of an R2MFC / CCT receiver using a digital signal processor. An EP (Erasable and Programmable) ROM (3) (4) and a channel multiplexing circuit (6) are focused on the digital signal processor (5). ), The input / output memory 2, the timing control circuit 10, and the microcontroller 1 collectively transmit this information for each received channel to the control apparatus. In this case, when the microcontroller 1 is notified, the microcontroller 1 organizes this information for each received channel and transmits the information to the controller.

Here, the microcontroller 1 reads it from the input / output memory 2 in which the signal information detected by the digital signal processor 5 is written, and arranges the received channel information for each received channel to the control device and the receiving device through the monitor 7. To monitor the operating state of the digital signal processor 5 by operating the reset circuit 9 when a failure occurs, and the input / output memory 2 stores the information detected by the digital signal processor 5. The communication area required to inform the host controller and to perform the matching function between the microcontroller 1 and the digital signal processor 5 for retrieving the function mode information to be performed by the digital signal processor 5 from the controller. The digital signal processor 5 receives the PCM data inputted through the channel multiplexing circuit 6, and then, by the signal receiving program built in the EP ROM 3, 4, After detecting the call information, the information is sent to the input / output memory 2, and the local oscillator 8 provides the clock frequency necessary for the operation of the digital signal processor 5, and the EP ROM 3 ( 4) a signal receiving program executed by the digital signal processor 5 is incorporated, and the reset circuit 9 receives a signal from the microcontroller 1 and resets the operation of the digital signal processor 5, The channel multiplexing circuit 6 selects only the necessary channel from the signal subhighway multiplexed into multiple channels so that the digital signal processor 5 can process multiple channels. The channel multiplexing circuit 6 receives a signal from the timing control circuit 10. It provides a function to send only the PCM data corresponding to the channel to be received by the digital signal processor 5 from the time switch device to the digital signal processor 5. The timing control circuit 10 receives the FS and CLK signals from the time switch device and generates and provides the signals required by the channel multiplexing circuit 10 and the monitor 7, and the monitor 7 provides a digital signal processor 5. And a signal from the timing control circuit 10 to monitor the operation state of the receiver and provide the monitored result to the microcontroller 1.

2 is an information area display diagram of the input / output memory 2 in the R2MFC / CCT receiving device, which is used to indicate performance function mode information that the digital signal processor 5 should receive and process. The controller 1 provides the channel signal to the digital signal processor 5. The information area is composed of data in units of 1 byte, and is represented by 1 bit to display the function mode information, and the D7 bit indicates the function mode information of the first channel in accordance with the channel order performed in the digital signal processor 5, The bit D6 indicates the function mode information of the second channel, and the channel-specific function mode information for the remaining bits. Therefore, the bit D0 indicates the function mode information of the eighth channel. If the bit value of each channel is '0', it indicates R2MFC function mode. If '1', it indicates CCT function mode.Increasing the information area when the number of service channels increases according to the signal processing capacity of the digital signal processor 5 In this manner, the function mode information for each channel may be displayed.

3 is a view showing the reception area of the input / output memory 2 in the R2MFC / CCT receiving device, which is used to transmit the signal information, which is the result of reception detection by the digital signal processor 5, to the microcontroller 1. FIG. . The receiving area is composed of data in 1 byte unit like the information area of FIG. 2, and all of 1 bytes are used to represent the received and detected signal information for each channel. Bits D0 to D3 indicate received and detected signal information. In the case of bits D4 to D7, the meaning differs depending on the function mode. In the CCT function mode, the meaning of the received and detected signal information is displayed. In the R2MFC function mode, the direction of the signal information is displayed.

Bits D0 to D3 indicating the signal information are different depending on the function mode being performed, and when executed in the R2MFC function mode, signal code information from 1 to 15 and a null signal means that there is no signal information. A total of three types of signal information, such as a zero signal code, is shown.

In the case of D4 to D7 bits, the meaning is different depending on the function mode.In other words, in the CCT function mode, when all of the D4 to D7 bits are set, the received detected signal information is valid. When all are reset, it indicates that the received and detected received information is an invalid value.In the R2MFC function mode, it indicates the direction of the signal information.When all of the D4 to D7 bits are set, it indicates the rear signal information and the D4 to D7 bits are displayed. When all are reset, the front signal information is displayed.

As described above, data types indicating the received results of the signals processed by the digital signal processor 5 are standardized into a single form, and information about the R2MFC and CCT signals is divided and displayed to efficiently communicate with the microcontroller 1. It becomes possible.

With the development of digital signal processing technology and semiconductor integrated circuit technology, the digital signal processor 5 has been developed to enable the development of a high performance signal service device that receives and detects digital signals. It is also possible to develop a function-multiplexing type signal service device capable of receiving and detecting city-type signals in multiple channels, which is a digital signal in response to changes in signal processing functions required according to operational conditions of the switching center. As a result of the principle that the program in the processor 5 can be dynamically changed and assigned, it is expected to have a significant effect on economic efficiency and efficiency of exchange bureau management.

Meanwhile, digital filter (DF) and discrete Fourier transform (DFT) methods are used as R2MFC / CCT signal detection methods. The DF method has better frequency detection characteristics than the DFT method. However, the R2MFC signal frequency detection does not require sensitive frequency characteristics but only discriminates the presence or absence of frequencies, and in particular, since the reference frequencies used are divided into equal intervals of 120 Hz, and voices are not mixed, the present patent Is a DFT calculation method that is effective to obtain the value at any one of the known DFT methods, and the signal is detected by the Goertzel method, which has a small coefficient and enables signal analysis in a sufficiently fast time. Therefore, the R2MFC / CCT combined receiver A digital signal processor 5 was used to implement a known Götzel method for detecting R2MFC signals. Only when the signal reception standard indicated in FIG. 1 is satisfied, the corresponding signal code information is detected and reception is completed.

Since the detection method of the CCT signal does not require sensitive frequency characteristics but requires a single frequency detection technique that only discriminates the presence or absence of a frequency, and also does not have a mixed voice signal, the present method is similar to the method used when detecting an R2MFC signal. The signal is detected by the Goechel method, which is one of the same known DFT methods, and accordingly, a known signal is implemented using the digital signal processor 5 in the R2MFC / CCT receiver. Only when the signal reception standard indicated in the figure is satisfied, the detection is completed by the corresponding signal code information.

The same Götzel method is used as the DFT calculation method for receiving and detecting the R2MFC signal and the CCT signal. However, since the reception specifications of the R2MFC signal and the CCT signal are different, the DFT calculation result is used to determine the signal code information. Since the determination parameters are different from each other in the case of the R2MFC signal and the CCT signal, the signals are received by different determination methods.

4 is a program flow diagram illustrating a multi-channel R2MFC / CCT combined reception method in the digital signal processor 5 of the present invention. The digital signal processor 5 receives and detects an R2MFC or CCT signal by performing this program. The process is as follows.

When the power is first turned on, the program starts to be executed, and initializes various data contents required for the multi-channel R2MFC / CCT receiving program to be executed in the digital signal processor 5 (11), and the PCM data is converted into the digital signal processor (5). (12) When PCM data is input, the performance function information sent from the microcontroller 1 is read from the information area of the input / output memory (2), and the digital signal processor (13) is checked. 5) after checking the sequence number of the channel to be processed (14), if it is the first channel, processes the relevant data before performing the signal detection process of the first channel (15), and if it is the second channel, the signal of the second channel Before performing the detection process, process the relevant data (16), and perform the corresponding signal detection process for each selected channel in the same manner. Previously, the associated data is processed before the signal detection process is performed on the N-th channel which the digital signal processor 5 can process (17), and the digital signal processor 5 can process the N channels. After having selected this step, the PCM data input to the digital signal processor 5 is converted into linear data by the memory look-up table method as a step to be performed in common when detecting the R2MFC and the CCT signal. (18), multiplying the window function with the linear data by the window function, calculating the power spectrum for each of the R2MFC and CCT signal frequency components by the DFT method (19), and then performing it according to the performance function information read in step (13). It is checked whether the function mode to be processed in the channel is R2MFC function or CCT function (20), and if it is determined that it is the R2MFC function, the DFT calculation result performed in step (19) is returned. The corresponding signal code information is detected by applying relevant parameters for detection and determination as the R2MFC signal code (21), and the digital signal processor (5) rechecks the sequence number of the channel to be processed (23). If the corresponding signal is processed after performing the signal detection process of the first channel (24), if the second channel is performed after the signal detection process of the second channel (25), and in the same manner After performing a signal detection process corresponding to each selected channel, the associated data is processed to perform the signal detection process on the N-th channel that the digital signal processor 5 can process (26). Only one selected channel among the N channels that can be processed by the digital signal processor 5 goes through this step, and is selected and processed in step 14 above. It should be disposed of in the same channel as the selected channel. After passing this step, it is repeatedly performed from step 12 for continuously checking whether the PCM data has been input into the digital signal processor 5, and checking whether the R2MFC function or the CCT function is performed ( If it is determined in step 20) that the CCT function is used, the relevant signal code information is detected by applying the relevant parameter for detecting and determining as a CCT signal code using the DFT calculation result performed in step 19 (22), and then the digital signal processor From step (23) of rechecking the sequence number of the channel to be processed by (5), the method is repeatedly performed in the same manner as the method performed by the R2MFC function.

In order to receive and detect the R2MFC and CCT signals as described above, the digital signal processor executed by the signal reception program in the digital signal processor 5 is used in the R2MFC / CCT combined receiver manufactured using the digital signal processor 5. According to the multi-channel R2MFC / CCT combined receiving method, it is possible to combine and receive the R2MFC signal and CCT signal input to multiple channels as a single device, and to dynamically process to different function modes for each channel performed during the function execution, The R2MFC receiver and CCT receiver, which are distributed and accommodated as their own devices in the exchange, can be implemented as a single device, resulting in significant improvements in economics, reliability, usability, maintainability, productivity, and efficiency. Only by changing and supplementing a program in the digital signal processor 5, there is an advantage in that it is easy to add a new function.

Claims (8)

Digital signal processor 5, EP ROM (3) (4), channel multiplexing circuit (6), input / output memory (2), monitor (7), reset circuit (9) and local connected to the digital signal processor (5). R2MFC / CCT with an oscillator 8, a microcontroller 1 connected to the input / output memory 2 and a monitor 7, the channel multiplexing circuit 6 and a timing control circuit 10 connected to a monitor 7 In the dual receiving apparatus, a first step of initializing (11) various data contents required for the multi-channel R2MFC / CCT dual receiving program to be executed in the digital signal processor (5), the PCM data is the digital signal processor (5). (12) If the PCM data is input, the function mode information sent from the microcontroller (1) is read from the input / output memory (2) and the digital signal is read. With the processor 5 to process A second step of determining (14) the sequence number of the third step; converting (18) the PCM data inputted to the digital signal processor (5) to linear data by a memory lookup table method after the second step, After the third step, multiply the window function to the linear data and calculate the power spectrum for each frequency component of the R2MFC and CCT signal by the DFT method (19). A fourth step of determining whether the function mode is an R2MFC function or a CCT function; if it is determined as the R2MFC function in the fourth step, a corresponding signal is applied by applying a relevant parameter for detecting and determining as an R2MFC signal code using the DFT calculation result; When the code information is detected and determined by the CCT function, the relevant parameter for detecting and determining as a CCT signal code using the DFT calculation result is applied. The fifth step of detecting code information, and after the fifth step, the digital signal processor 5 determines the sequence number of the channel to be processed, processes the data after performing the function of the corresponding channel, and then starts again from the second step. A multi-channel R2MFC / CCT combined receiving method comprising a sixth step of repeating it. The method of claim 2, wherein in the second step, when the sequence number of the channel is the first channel, the associated data is processed before the signal detection process of the first channel is performed. Multiplex channel R2MFC / CCT combined receiving method comprising the step of processing the related channel before performing. The method of claim 1, wherein the sixth step processes the related data after performing the signal detection process of the first channel when the sequence number of the channel is the first channel, and performs a signal detection process corresponding to each channel selected by the same method. Multi-channel R2MFC / CCT combined receiving method comprising the step of processing the relevant data after performing. The information area of the input / output memory (2) according to claim 1, wherein the digital signal processor (5) is used to indicate performance function mood information to be received and processed by the microcontroller (1). Multi-channel R2MFC / CCT combined receiving method comprising a byte unit of data, characterized by one bit to display the function mode information for each channel. 5. The method of claim 4, wherein the D7 bit of the 1-byte data indicates the function mode information of the first channel, the D6 bit indicates the function mode information of the second channel, and the sequential channel-specific function information for the remaining bits. D0 bit is a multi-channel R2MFC / CCT receiving method characterized in that configured to indicate the function mode information of the eighth channel in order. The multi-channel R2MFC / CCT combined receiving method according to claim 1, wherein the receiving area of the input / output memory (2) is composed of data in units of 1 byte. 7. The multi-channel R2MFC / CCT combined receiving method according to claim 6, wherein the 1-byte data D0 through D3 bits indicate received and detected signal information. 8. The data of claim 1, wherein the D4 to D7 bits indicate the meaning of the received and detected signal information in the CCT function mode, and the direction of the signal information in the R2MFC function mode. Multi-channel R2MFC / CCT combined receiving method.