JP2571007B2 - Bipolar signal switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bipolar signal switching device, and more particularly to a bipolar signal switching device for switching between a working and protection bipolar signal without causing a signal error.

[0002]

2. Description of the Related Art In a conventional bipolar signal switch, FIG.
As shown in the figure, the working and backup unipolar data clocks are applied to the phase shifters 6 and 7, respectively, to control the amount of delay. The outputs of the phase shifters 6 and 7 are output from the unipolar / bipolar converters 8 and 9, respectively. The signals are converted into bipolar signals, and both bipolar signals are input to the switch 13. The switch 13 selects and outputs either a working signal or a protection signal according to a control signal externally applied to the terminal 3. The phase shift polarity detector 12 detects a phase difference and a match between polarities of the working and backup signals. Here, the output of the polarity switch 10 is used for the current operation, and the output of the signal converter 9 is used for the standby. The operator sees the phase difference and the limit with the detector 12 and checks the phase shifters 6 and 7.
The polarity and the polarity of the two bipolar signals are matched by the polarity switch 10.

[0003] Japanese Patent Application Laid-Open No. 54-128644 discloses a circuit for switching only a clock between a working mode and a standby mode.

[0004]

In the conventional bipolar signal switch shown in FIG. 2, the phase and polarity detectors 12 detect the phases and polarities of two signals, and the phase shifters 6, 7 and the polarity switch 1
Although the phase and polarity are matched at 0, the switch 13
The switching timing is arbitrary. In this case, if the identification timing of the bipolar identification circuit in the receiving end device (transmission terminal device) connected to the subsequent stage of the output of the switch 13 matches the timing of switching by the switch 13, the signal is identified during the transition period of signal switching. Will do
Signal errors may occur at the receiving device.

[0005]

In order to solve the above-mentioned problem, the present invention provides a first phase shifter for changing a delay amount of a first unipolar signal, and a first phase shifter for changing a delay amount of the first unipolar signal. Signal conversion / polarity switching means for converting the unipolar signal output from the device into a first bipolar signal and inverting the polarity of the first bipolar signal as necessary, in the first signal system, A second phase shifter for changing a delay amount of the second unipolar signal; and a signal converting means for converting the unipolar signal output from the second shifter to a second bipolar signal, in a second signal system. In addition to the first
And the phase difference and polarity of the second bipolar signal match.
A bipolar signal switch comprising a detector for detecting a mismatch and a switch for selecting and outputting one of the first and second bipolar signals, wherein the first or second bipolar signal is asynchronous with the first bipolar signal. A flip-flop for receiving a control signal given from the outside and generating a signal for controlling switching of the switch, the flip-flop receiving a clock signal from the first or second signal system and synchronizing with the clock signal; Generating a signal corresponding to the external control signal as the switch switching control signal to switch the switch in accordance with the rising edge of the first or second bipolar signal. It is a vessel.

[0006]

Next, an embodiment of the present invention will be described with reference to FIG.

The two sets of working and protection unipolar data input to terminals 1 and 4 and the clock input to terminals 2 and 5 are input to phase shifters 6 and 7, respectively, and are given delay. Outputs of the phase shifters 6 and 7 are applied to signal converters 8 and 9 and converted into bipolar data. A polarity switch 10 is provided on the signal converter 8 side so that the polarity of the bipolar signal can be arbitrarily selected. The switch 13 selects and outputs one of the two sets of bipolar signals. The phase polarity detector 12 detects the phase difference between the two sets of bipolar signals and the coincidence of the polarities. The operator operates the phase polarity detector 1
2, based on the phase difference and the polarity detected by the phase shifter 6,
7 and the polarity switch 10 are adjusted to match the phases and poles of the two sets of bipolar signals.

A D-type flip-flop 11 receives a current / preliminary switching control signal input from the outside to a terminal 3 at a data terminal D, and outputs a clock output from the phase shifter 7 to a clock terminal C.
To

In this state, when a current / preliminary switching control signal for switching the switch 13 is received from the terminal 3, the timing for actually driving the switch 13 is made coincident with the rising edge of the bipolar signal by the flip-flop 11.
The receiving device that receives the output of the switch 13 identifies the bipolar signal while avoiding a timing that may cause an identification error such as a rising edge of the signal. Therefore, if the switching timing of the bipolar signal by the switch 13 is made to coincide with the rising point of the bipolar signal by adopting the present embodiment, it is possible to prevent the occurrence of a signal error due to the identification of the signal switching transient device. Wear.

In the embodiment shown in FIG. 1, the signal system of the phase shifter 6, the signal converter 8 and the pole switch 10 corresponds to the first signal system described above, and the system of the phase shifter 7 and the signal converter 9 corresponds to the first signal system. This corresponds to the second signal system described above. For example, the first signal system is used as an active system, and the second signal system is used as a standby system.

A terminal 3 is supplied with a working / standby switching control signal from an alert detection device monitoring an abnormality of the working system and the protection system.

[0012]

As described above, according to the present invention,
By matching the phases and polarities of the two working and spare bipolar signals in advance and matching the switching timing of the signals to the rising edge of the bipolar signal, the switching of the bipolar signal by the switch can be performed at a time when there is no risk of bit error. You can do it.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of one embodiment of the present invention.

FIG. 2 is a block circuit diagram showing a conventional bipolar signal switch.

[Explanation of symbols]

 6,7 Phase shifter 8,9 Unipolar / bipolar signal converter 10 Polarity switch 11 Flip-flop 12 Phase polarity detector 13 Switch

Claims (2)

(57) [Claims] 1. A first phase shifter for changing a delay amount of a first unipolar signal, a unipolar signal output from the first phase shifter being converted into a first bipolar signal, and A signal conversion / polarity switching means for inverting the polarity of the bipolar signal as required in the first signal system, and a second phase shifter for changing the delay amount of the second unipolar signal; Signal conversion means for converting a unipolar signal output from the second transporter into a second bipolar signal in a second signal system, further comprising a phase difference and a polarity difference between the first and second bipolar signals. A detector for detecting a match / mismatch;
And a switch for selecting and outputting one of the second bipolar signal, wherein the switch receives an externally applied control signal asynchronously with the first or second bipolar signal, A flip-flop for generating a signal for controlling the switching of the clock signal, the flip-flop receiving a clock signal from the first or second signal system, and synchronizing with the clock signal to generate a signal corresponding to the external control signal. A bipolar signal switch, wherein the switch is switched in accordance with a rise of the first or second bipolar signal by generating the switch as a switch switching control signal. 2. The flip-flop according to claim 1, wherein the flip-flop is a D-type flip-flop. The external control signal is input to a data terminal D, and a clock signal output from the second transfer unit is input to a clock terminal C. The bipolar signal switch according to claim 1, wherein: