JPH04307835A - Ami code pulse generating circuit - Google Patents

Abstract

PURPOSE:To eliminate an undershoot/overshoot of a pulse by changing a switching time of a switch in an AMI code generating circuit. CONSTITUTION:In the case of transmission of '+1' in an AMI code, only switches (1), (2) are switched and the timing of control signals (3), (4) are adjusted so as to give a small delay to the switch (2) for the OFF timing. Similarly, in the case of transmission of '-1' in the AMI code, only switches(3), (4)are switched and control signals (5), (6) are adjusted so that the off-timing of the switch (4) has a small delay thereby sufficiently discharging a space energy of a transformer 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to AMI code pulse generation, and more particularly to an AMI code pulse generation circuit that eliminates pulse undershoot and overshoot by changing the switching time of a switch.

0002

[Prior Art] Fig. 3 shows a conventional AMI code pulse generation circuit disclosed in the Proceedings of the 1984 IEICE Communication Section National Conference Proceedings 561. In the figure, 1 connects the transformer and power supply only when transmitting "+1". Switch to connect, 2 is “+1”
``A switch that connects the transformer and ground only during transmission,
3 is a switch that connects the transformer and power supply only when transmitting "-1", 4 is a switch that connects the transformer and ground only when transmitting "-1", 5 is a transformer, and A is a control signal that switches switch 1 and switch 2. (1) and B are control signals (2) for switching the switches 3 and 4.

Next, the operation will be explained. When transmitting "+1", only switch 1 and switch 2 are turned on by control signal (1)A, so that current flows through transformer 5 in the direction from a to b, generating a "+1" sign. Then “-1”
At the time of transmission, only the switches 3 and 4 are turned on by the control signal (2)B, so that current flows through the transformer 5 in the direction from b to a, generating a "-1" sign. Then “0”
During transmission, switches 1 to 4 are turned off to prevent current from flowing through the transformer 5. The AMI code pulse is generated by the method described above. A timing chart of the control signal (1) and control signal (2) is shown in FIG.

0004

[Problems to be Solved by the Invention] Since the conventional AMI code pulse generation circuit is configured as described above, even if the switch connecting the transformer and the power supply and the switch connecting the transformer and the ground switch simultaneously, there is a time lag. The switch that connects the transformer and ground may turn off faster. At this time, there were problems such as the space energy of the transformer could not be sufficiently discharged, resulting in undershoots and overshoots in the generated pulses.

[0005] This invention was made in order to solve the above-mentioned problems, and without increasing the circuit scale,
An object of the present invention is to obtain an AMI code pulse generation circuit that generates an AMI code pulse with undershoot and overshoot removed from the pulse.

[0006]

[Means for Solving the Problems] An AMI code pulse generation circuit according to the present invention provides a "+1" signal in an AMI code whose switching operation is controlled by each separate control signal.
A switch that connects the transformer and power supply during transmission, and a “+1
``A switch that connects the transformer and ground during transmission,
It is equipped with a switch that connects the transformer and the power supply when transmitting "-1", a switch that connects the transformer and the ground when transmitting "-1", and a transformer that is controlled by the operation of each of the switches.

[0007]

[Operation] In the AMI code pulse generation circuit of the present invention, a control signal is given to each switch so that the switch connecting the transformer and the ground is turned off later than the switch connecting the transformer and the power supply, and the spatial energy of the transformer is sufficiently discharged. By doing so, undershoot and overshoot are removed from the generated pulse.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an AMI code pulse generation circuit according to the present invention. In the figure, 1 is a switch that connects the transformer and power supply only when transmitting "+1", and 2 is a switch that connects the power supply only when transmitting "+1".
1 is a switch that connects the transformer and the ground only when transmitting, 3 is a switch that connects the transformer and the power supply only when transmitting "-1", 4 is a switch that connects the transformer and ground only when transmitting "-1", 5 is a transformer , C is a control signal (3) for switching switch 1, D is a control signal (4) for switching switch 2, E is a control signal (5) for switching switch 3, and F is a control signal for switching switch 4 ( 6).

Next, the operation will be explained. When transmitting "+1", control signal (3)C controls switch 1, and control signal (
4) By turning on the switch 2 using D, current flows through the transformer 5 in the direction from a to b, generating a "+1" sign. Next, when transmitting "-1", switch 3 is turned off with control signal (5) E, and switch 4 is turned off with control signal (6) F.
N, current flows in the transformer 5 from direction b to a, generating a "-1" sign. Next, when transmitting "0", switches 1 to 4 are turned off to prevent current from flowing through the transformer 5.

FIG. 2 shows a timing chart of control signals (3) to (6). That is, control signals (4), (
6), the switches 2 and 4 are controlled to turn off later than the switches 1 and 3. As a result, the spatial energy of the transformer 5 is sufficiently discharged, and undershoots and overshoots can be removed from the generated pulses.

Although the above embodiment has described the generation of AMI code pulses, similar effects can be expected with respect to other code pulses according to the present invention.

[0012] Regarding the switches described above, transistors or FETs may be used.

[0013]

As described above, according to the present invention, undershoots and overshoots can be removed from generated pulses simply by changing the timing of the switches, without increasing the circuit scale.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an AMI code pulse generation circuit according to the present invention.

FIG. 2 is a timing chart of control signals showing switching times of each switch in the AMI code pulse generation circuit according to the present invention.

FIG. 3 is a circuit diagram showing a conventional AMI code pulse generation circuit.

FIG. 4 is a timing chart of control signals showing switching times of each switch in a conventional AMI code pulse generation circuit.

[Explanation of symbols]

1 Switch 2 Switch 3 Switch 4 Switch 5 Transformer

Claims (2)

[Claims] 1. A switch that connects a transformer and a power supply when transmitting a "+1" in an AMI code, and a switch that connects a transformer and a ground when transmitting a "+1" in an AMI code, each of which has a switching operation controlled by a separate control signal; −
1" A switch that connects the transformer and power supply during transmission, and
-1'' An AMI code pulse generation circuit characterized by comprising a switch that connects a transformer and a ground during transmission, and a transformer that is controlled by the operation of each of the switches. 2. The AMI code according to claim 1, wherein the AMI code according to claim 1 is controlled by a control signal for each switch so that the switch connecting the transformer and the ground is turned off later than the switch connecting the transformer and the power source. Pulse generation circuit.