JP2003069541A - Protection circuit of clock inversion control circuit for v.35 interface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data generation device in a communication system for communication between an NT side device with a V.35 interface and TE side equipment in which a received data error is caused as the device is immune to noises on a transmission line. SOLUTION: A network data generating device for a V.35 interface in the NT side device with a V.35 interface for generating network data by sampling the received data from the TE side equipment is provided with a protection means with an inversion control means capable of inverting a sampling clock phase when a conversion point of the received data falls in any one of guard areas set in the vicinity of the conversion points. The protection means is configured to invert the sampling clock phase only if the conversion point is in the guard area for a certain period of time or more.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an NT (Network # Terminati) having a V.35 interface in the field of data communication.
ng # Equipment: Network terminating equipment side equipment and TE (Terminal # Eq)
uipment: Terminal device) side device, NT side device T
When sampling the transmission data from the E side device,
The present invention relates to a communication device that realizes high-quality data communication without being affected by delay of input data on a transmission line or noise.

[0002]

2. Description of the Related Art In data communication between an NT-side device having a V.35 interface and a TE-side device, the NT-side device is
The RT clock and RD data are transmitted to the E side device. Further, the TE side device uses a mode in which only TD data is transmitted to the NT side device.

In the data communication in this form, the TE side device outputs the TD data in synchronization with the RT clock transmitted from the NT side device. However, when the TD data is noisy or when the cable is disconnected / attached. When such chatter is present, the switching operation of the sampling clock in the NT side device is not performed correctly and the received TD data cannot be sampled correctly, so that high quality data communication cannot be realized. Conventionally, sufficient measures have not been taken against such malfunctions.

Next, problems in data communication between the NT side device and the TE side device having the conventional V.35 interface will be described in detail with reference to FIGS. 1 and 2. Figure 1
FIG. 6 is a diagram showing a configuration of a conventional NT side device and TE side device. In FIG. 1, 1 is an NT-side device, which is composed of a synchronous clock generator 1-1 and a network data generator 1-2. The synchronous clock generator 1-1 includes a phase comparator 1-1a, a VCO 1-1b, and frequency dividers 1-1c and 1-1d. The network data generator 1-2
Inversion controller 1-2a, guard range generator 1-2b, data synchronizer
1-2c and a data generation circuit 1-2d are included. 2 is T
A synchronization circuit for transmitting the TD data in synchronization with the RT clock transmitted from the NT side device, which is the E side device 2-
Contains 1

In the data synchronization section 1-2c, the received TD data ((c) in FIG. 2) is used as a sampling clock pulse ((b) in FIG. 2) as a multiplication clock (VCOOUT) before frequency division.
By sampling in (FIG. 2 (a)), a conversion point pulse ((d) in FIG. 2) in which the conversion point of the TD data is detected is generated.

In the protection range generation section 1-2c, with respect to the sampling clock for sampling the received TD data, the normal phase guard range indicating a dangerous area synchronized with the rising and falling of the sampling clock (see FIG. 2 (e)) and the antiphase guard range (FIG. 2 (f)) are generated.

When the conversion point pulse enters the guard range (dangerous area) of the sampling clock used, the inversion controller 1-2a outputs a switching selection signal to use the inverted sampling clock. . in this way,
By inverting the sampling clock, the sampling time point is moved away from the dangerous area which is the conversion point of the TD data.

[0008]

Next, FIG. 3 shows the conventional details of the inversion control circuit of FIG. In FIG. 3, the guard range for positive phase ((e) of FIG. 2) or the guard range for antiphase (of FIG. 2)
One of (f)) is selected by the switching selection signal ((g) of FIG. 2) in the switching circuit 31. In this case, T
When the rising edge of the clock is used as the sampling clock of the D data, the normal phase guard and the conversion point pulse are compared by the phase comparison circuit 32, and the falling edge of the clock is used as the sampling clock of the TD data. , The anti-phase guard and the conversion point pulse are compared by the phase comparison circuit 32. Then, the level of the switching selection signal is inverted so that the TD data is sampled at the fall (rise) of the sampling clock when the phases of the two coincide. With the switching of the sampling pulse, the selection of the normal phase guard range and the antiphase guard range can be switched.

Therefore, in the conventional inversion control circuit, the sampling clock phase is compared with the phase of the change point of the TD data, and when the phases overlap, the selection of the sample clock is switched by the switching selection signal. When noise is superimposed on the TD data, the sample clock switching may occur erroneously as shown in B of FIG.

Further, according to the conventional knowledge shown in FIG. 1, since the clock switching selection signal is continuously generated even for the chatter when the cable is inserted, it takes a long time to become stable. It was from these things,
In some cases, high quality data communication could not be guaranteed.

Another object (object) of the present invention is to eliminate a reception data error without being affected by noise on a transmission line in a communication system for executing data communication between an NT side device and a TE side device having a V.35 interface. It is to realize a data generation device that does not cause this.

[0012]

In order to solve the above-mentioned problems, in an NT side device having a V.35 interface, a network data generation device for generating received data from a TE side device by sampling, Of the received data, a guard range is set before and after the data conversion point, and when the conversion point enters the guard range, it includes inversion control means for inverting the phase of the sampling clock, and the inversion control means performs the conversion. A V.35 interface network data generation device is configured by providing a protection means for inverting the phase of the sampling clock only when a point continuously enters the guard range for a predetermined period or longer. (Claim 1)

Further, the protection means includes a dangerous pulse counter, and when the dangerous pulse counter determines that the conversion point continuously enters the guard range for a predetermined period or longer, the phase of the sampling clock is changed. The switching signal to be inverted is output. (Claim 2) Further, the protection means includes a safety pulse counter,
The dangerous pulse counter is cleared when the safety pulse counter determines that the conversion point does not continuously enter the guard range for a predetermined period or longer. (Claim 3) Further, regarding the relationship between the set value of the dangerous pulse counter and the set value of the safety pulse counter, the set value of the safety pulse counter is made larger than the set value of the dangerous pulse counter.
(Claim 4)

Further, in the network data generating method in the NT side device having the V.35 interface to generate the received data from the TE side device by sampling, in the guard range before and after the data conversion point of the received data from the TE side device. And a phase inversion step that adds a protection function that inverts the phase of the sampling clock only when the conversion point continuously enters the guard range for a predetermined period or more. Generate data.
(Claim 5)

Further, the protection function includes a dangerous pulse counter, and when the dangerous pulse counter determines that the conversion point continuously enters the guard range for a predetermined period or more, the phase of the sampling clock is changed. A switching signal for inversion is output. (Claim 6) Further, the protection protection function includes a safety pulse counter, and when the safety pulse counter determines that the conversion point is not continuously within the guard range for a predetermined period or more, Clear the dangerous pulse counter.
(Claim 7) Further, regarding the relationship between the set value of the dangerous pulse counter and the set value of the safety pulse counter, the set value of the safety pulse counter is made larger than the set value of the dangerous pulse counter.
(Claim 8)

As described above, according to the present invention, the switching signal output section is provided with the counter for comparing the phase of the sample clock with the phase of the change point of the TD data and for counting when the phase approaches the dangerous area. This can be realized by providing protection for switching the sample clock when the state continues for a predetermined period (for example, 1 second).

[0017]

FIG. 4 shows the details of the inversion control circuit of the present invention. In FIG. 4, a protection circuit is further added to the conventional inversion control circuit of FIG. 4, either the normal phase guard range ((e) in FIG. 2) or the antiphase guard range ((f) in FIG. 2) is switched by the switching circuit 41 to the switching selection signal ((g in FIG. 2). )) Is selected. In this case, when the rising edge of the clock is used as the sampling clock of the TD data, the normal phase guard and the conversion point pulse are compared by the phase comparison circuit 42, and the falling edge of the clock is used as the sampling clock of the TD data. If so, the phase comparison circuit 42 compares the antiphase guard with the conversion point pulse.

The guard range and the conversion point pulse are compared, and when the conversion point pulse falls within the guard range, it is determined as a dangerous pulse,
When the conversion point pulse is not within the guard range, it is input to the protection circuit 15 as a safety pulse.

Next, details of the protection circuit will be described with reference to FIG. The protection circuit of FIG. 5 includes a dangerous pulse counter 5a and a safety pulse counter 5b, and has a configuration in which VCOOUT, a dangerous pulse and a safety pulse are input and a switching signal is output.

The dangerous pulse input to the protection circuit counts one second of the TD data by the dangerous pulse counter 5a, and the conversion point of the TD data and the sampling clock for sampling the TD data is surely close to each other for one second. If it continues, the switching signal is output. Further, the safety pulse input to the protection circuit is counted by the safety pulse counter 5b for 10 seconds of the TD data, and when the safety state continues for 10 seconds, a clear signal for the dangerous pulse counter is output. The dangerous pulse counter 5a is cleared even when the dangerous pulse counter overflows.

As described above, by adding the protection circuit as shown in FIG. 5 to the inversion control circuit, the conversion point pulse falls within the guard range when noise is added to the TD data or due to the influence of chatter due to the cable being inserted or removed. If the signal is entered once, the sampling pulse is not switched. Therefore, N with V.35 interface
In a communication system that performs data communication between a T-side device and a TE-side device, it is possible to realize a data generation device that does not cause a reception data error without being affected by noise on the transmission path.

[0022]

According to the invention described in claim 1, in the network side data generating apparatus which is the NT side apparatus having the V.35 interface and generates the reception data from the TE side apparatus by sampling, the reception data from the TE side apparatus is obtained. A guard range is set before and after the data conversion point, and when the conversion point enters the guard range, it includes inversion control means for inverting the phase of the sampling clock, and the conversion point is within the guard range for a predetermined period. A protection means is provided to invert the phase of the sampling clock only when the input is continued for the V.
35 Configure network data generator for interface. With this configuration, in data communication between NT-TE with V.35 interface, it takes time to stabilize due to malfunction due to noise on TD data or chatter due to cable removal and insertion. It is possible to realize a high-quality data communication environment that can be prevented, is not affected by noise, and has no received data error.

Further, in the invention according to claim 2, the protection means includes a dangerous pulse counter, and it is determined by the dangerous pulse counter that the conversion point has continuously entered the guard range for a predetermined period or more. In this case, it is possible to realize a high-quality data communication environment that is not affected by noise and has no received data error with a simple configuration that outputs a switching signal that inverts the phase of the sampling clock. Further, in the invention according to claim 3, the protection means includes a safety pulse counter, and it is determined by the safety pulse counter that the conversion point is not continuously within the guard range for a predetermined period or more. In this case, the dangerous pulse counter can be cleared. In the invention according to claim 4, the relationship between the set value of the dangerous pulse counter and the set value of the safety pulse counter is set such that the set value of the safety pulse counter is larger than the set value of the dangerous pulse counter. Any setting that is compatible with is possible.

According to the invention of claim 5, in an NT side device having a V.35 interface, in the network data generating method for generating the reception data from the TE side device by sampling, the reception data from the TE side device is Of setting a guard range before and after the data conversion point, and a phase inversion step adding a protection function of inverting the phase of the sampling clock only when the conversion point continuously enters the guard range for a predetermined period or longer. And generate network data for V.35 interface. According to this method, in data communication between NT-TE with V.35 interface, it may take time to stabilize due to malfunction due to noise on TD data or chatter due to cable removal and insertion. It is possible to realize a high-quality data communication environment that can be prevented, is not affected by noise, and has no received data error.

Further, in the invention according to claim 6, the protection function includes a dangerous pulse counter, and it is determined by the dangerous pulse counter that the conversion point has continuously entered the guard range for a predetermined period or more. In this case, with a simple configuration that outputs a switching signal that inverts the phase of the sampling clock, it is possible to realize a high-quality data communication environment that is not affected by noise and has no received data error. In addition, claim 7
In the invention described in (1), the protection protection function includes a safety pulse counter, and when the safety pulse counter determines that the conversion point does not continuously enter the guard range for a predetermined period or more, You can clear the dangerous pulse counter. In the invention according to claim 8, the relation between the set value of the dangerous pulse counter and the set value of the safety pulse counter is that the set value of the safety pulse counter is larger than the set value of the dangerous pulse counter. It is possible.

As described above, in the present invention, the switching signal output section is provided with the counter that compares the phase of the sample clock with the phase of the change point of the TD data and counts when the phase approaches the dangerous area. This can be realized by providing protection for switching the sample clock when the state continues for a predetermined period (for example, 1 second), and the danger counter is cleared when the safe state continues for the predetermined period (for example, 10 seconds).

Therefore, in data communication between NT-TEs having a V.35 interface, it may take time to stabilize due to a malfunction due to noise on TD data or the influence of chatter due to the removal and insertion of a cable. Therefore, it is possible to realize a high-quality data communication environment that is not affected by noise and has no received data error.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a communication device using a conventional V.35 interface.

FIG. 2 is a timing chart of the operation of a conventional circuit.

FIG. 3 is a diagram showing a configuration of a conventional inversion control circuit.

FIG. 4 is a diagram showing a configuration of an inversion control circuit to which a protection circuit according to the present invention is added.

FIG. 5 is a diagram showing a detailed configuration of a protection circuit according to the present invention.

[Explanation of symbols]

10 Positive range guard range signal 12 Anti-phase guard range signal 13 Conversion point pulse signal 14 VCO output pulse 15 Protection circuit 16 switching signal 41 Switching circuit 42 Phase comparison circuit

Claims (8)

[Claims] 1. An NT side device having a V.35 interface, which is a network data generation device for generating the reception data from the TE side device by sampling, in a guard range before and after a data conversion point of the reception data from the TE side device. And including a reversal control means for reversing the phase of the sampling clock when the conversion point enters the guard range, and the reversal control means is configured to continuously convert the conversion point into the guard range for a predetermined period or longer. A network data generation device for V.35 interface, which is provided with a protection means for inverting the phase of the sampling clock only when it enters. 2. The protection means includes a dangerous pulse counter, and when the dangerous pulse counter determines that the conversion point continuously enters the guard range for a predetermined period or more, the phase of the sampling clock is changed. The V. according to claim 1, wherein a switching signal for inverting is output.
35 Network data generator for interface. 3. The safety means includes a safety pulse counter, and when the safety pulse counter determines that the conversion point is not within the guard range for a predetermined period or more, the dangerous pulse is detected. The network data generating device for V.35 interface according to claim 2, wherein the counter is cleared. 4. The relationship between the set value of the dangerous pulse counter and the set value of the safety pulse counter is that the set value of the safety pulse counter is larger than the set value of the dangerous pulse counter. V.35 interface network data generator. 5. In a network data generation method in an NT side device having a V.35 interface for generating received data from a TE side device by sampling, a guard range is provided before and after a data conversion point of the received data from the TE side device. And a phase inversion step in which a protection function for inverting the phase of the sampling clock is added only when the conversion point continuously enters the guard range for a predetermined period or more. Network data generation method for V.35 interface. 6. The protection function includes a dangerous pulse counter, and when the dangerous pulse counter determines that the conversion point continuously enters the guard range for a predetermined period or more, the phase of the sampling clock is changed. 6. The V. according to claim 5, wherein a switching signal for inverting is output.
35 Network data generation method for interface. 7. The safety protection function includes a safety pulse counter, and when the safety pulse counter determines that the conversion point has not continuously entered the guard range for a predetermined period or more, the danger is detected. 7. The V.35 interface network data generation method according to claim 6, wherein the pulse counter is cleared. 8. The relationship between the set value of the dangerous pulse counter and the set value of the safety pulse counter is such that the set value of the safety pulse counter is larger than the set value of the dangerous pulse counter. Network data generation method for V.35 interface.