JPS6387817A - Signal switching device - Google Patents

Abstract

PURPOSE:To contrive to stabilize the performance while decreasing the number of gates of the entire system by using a switch circuit so as to make circuits to be employed together in use in common even in the circuit system with different signal processing. CONSTITUTION:Switch circuit 14, 15 and 18 are added. An output of the switch 14 is supplied to a 1st series circuit 12' as the input, and its output is supplied to an input (a) of a switch 4 controlled by a signal fed to a control terminal 5 and an input (a) of the switch 18 controlled by a signal fed to a control terminal 8. Moreover, the output the switch 15 is fed to a 1st series circuit 12'' as the input and its output is fed to an input (b) of the switch 4 and an input (b) of the switch 18. The output of the switch 18 is supplied to a 2nd series circuit 13 and the output of the 2nd series circuit is fed to a terminal 20. Thus, the 1st series circuit 12'' on the signal line of a signal B is used in common with the 1st series circuit 12' of the signal line of a signal A in common and the number of gates is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a signal switching device in a digital video signal processing circuit.

Conventional technology A circuit for processing an input signal as a digital video signal, processing the signal, and outputting the signal will be explained with reference to FIG.

Now, the two terminals 1 and 11 are connected to the signal ``person'' and the signal ``B''.
A signal is supplied. Assuming that there are state (2) and state..., in state I, signal A supplied to terminal 1 is processed through state 1 passing circuit 2, selected by switching circuit 4, and output to terminal 1o. In state (2), the signal A supplied to terminal 1 passes through state (2) passing circuit 3, undergoes signal processing, is selected by switching circuit 4, and is output to terminal 10:.

The signal B connected to the terminal 11 separately from this line is processed through the first series circuit 12 and the second series circuit 13 (the order may be reversed), regardless of state 1.1. , is output to terminal 20.

Problems to be Solved by the Invention In the block diagram illustrated in FIG. 3, the respective circuit blocks of the two independent signal lines do not have the same function. However, when using digital signal processing, for example, when considering integrated circuits such as gate arrays, if the number of gates exceeds a predetermined number, the chip cost will increase gradually, so it is necessary to reduce the number of gates as much as possible. arise.

In conventional circuits, each signal line requires its own circuit, which requires a large number of gates.

In view of the above-mentioned problems, the present invention attempts to provide a device with a simple configuration by using switch circuits to share common circuits as much as possible.

Means for Solving the Problems The present invention provides a method for solving problems even if the signal processing is performed using a completely different circuit system.
If there is a circuit that can be used in common, we try to share it as much as possible.

It has a first input terminal and a second input terminal, the first input terminal is connected to two different circuits A and B, and the output signal of the circuit A and the signal from the second input terminal are input. A first switch is provided that outputs one of the signals from the circuit B, and a second switch is provided that inputs all the output signals of circuit B and the signals from the second input terminal, and outputs all of one of the signals. Circuits C1 and a2 having the same configuration are connected to the output terminal of the second switch, and a third switch and a fourth switch are provided, respectively, which receive the output signal of the circuit C4 and the output signal of the circuit C2. In this state, the first switch receives the output signal from circuit A, the second switch receives the output signal from the second input terminal, the third switch receives the output signal from circuit A, and the fourth switch receives the output signal from circuit A. respectively receive the output signal from the circuit C2, and in the second state, the first switch receives the output signal from the second input terminal, and the second switch receives the output signal from the circuit B'ff:% The present invention is characterized in that the switch receives the output signal from the circuit C2, and the fourth switch receives the output signal from the circuit C4.

Effects According to the configuration of the present invention, by using switch circuits and using common circuits as much as possible, the overall configuration can be simplified, and performance can be stabilized and costs can be reduced. be.

Embodiment FIG. 1 shows a block diagram of an embodiment of the present invention that solves the above problems. In FIG. 1, the signal person is connected to terminal 1. and is supplied to the state 1 pass circuit 6 excluding the first series circuit 12'. The output of this circuit 6 is supplied to the input a side of a switch 14 which is controlled by a signal applied to a control terminal 16. - On the other hand, the terminal 1 is also connected to the state (2) passing circuit 7 excluding the first series circuit 12'. The output of this circuit T is supplied to the input λ side of a switch 15 which is controlled by a signal applied to a control terminal 17. The terminal 11 is connected to the input side of the switches 14 and 15, and the signal B is input thereto. The output of the switch 14 is supplied as an input to the first series circuit 12', and its output is connected to the input a14N of the switch 40, which is controlled by the signal applied to the control terminal 6, and the input of the switch 18, which is controlled by the signal applied to the control terminal 8. It is input to the a side. Further, the output of the switch 15 is supplied as an input to the first series circuit 12', and its output is supplied to the input side of the switch 4 and the input side of the switch 18. The output of switch 4 is supplied to terminal 10, the output of switch 18 is input to second series circuit 13, and the output of the second series circuit is supplied to terminal 20. State 1 passing circuit 6 excluding the first series circuit, switch 14 and first series circuit 1
2' is the same as the state 1 passing circuit 2 shown in FIG. is the same as the state ① passing circuit 3 in FIG. 2, and the first series circuits 12, 12', 12' have the same circuit configuration, and three names are changed for distinction.

In Figure 1, signal person and signal B are connected to terminals 1 and 11 respectively.
added to.

(1) In state I Switches 14, 15, 4.18 are respectively a.

Control terminals 16.17 and 5.8 of the respective switches are controlled to select b*'*bIt.

As a result, the signal person passes through terminal 1 → state I passing circuit 6 → switch 14 → first series circuit 12' → switch 4 → terminal 10, and signal B passes through terminal 11 → switch 15 → first series circuit 12' → Switch 18 → second series circuit 13 → terminal 2o
Pass through the route.

(11) When state ■ Switches 14, 15, and 4.8 are respectively.

The control terminals 16, 17 and 5.8 of each switch are controlled to select a+b+ae. As a result, the signal is transferred from terminal 1 to state passing circuit 7 to switch 15 to
Passes through the first series circuit 12' - switch 4 → terminal 10,
Signal B is terminal 11 - switch 14 - first series circuit 12'
- Passes through the path from switch 18 to second series circuit 13 to terminal 20.

By adding the switch circuits 14, 16, and 18i as described above, the first series circuit conventionally used in the signal line of signal B can be shared with the first series circuit of the signal line of the signal person, and the number of gates can be reduced.

A specific example of the present invention is shown in FIG. FIG. 3 shows the case where the first series circuit'zn latch circuits are used.

If an s-bit video signal is created using 12Un D latches in the first series circuit, the first series circuit (12°12', 1
2' is the same) The number of gates of one D latch differs slightly depending on the process etc., but it is approximately 5 gates 71
It is individual. Therefore, the first series circuits 12, 12',
12' requires 5×8×n==4On gates. Also, since the switch circuit usually requires 2 gates/1 piece, the switches 14, 16, and 18 are each 2X8X3
= 48 gates increase. Therefore, the increase/decrease number of gates in FIG. 3 is (48-4 on) gates. As can be seen from this value, when n=2, the D latch has 132 gates, and as n increases, the number of gates can be reduced.

Effects of the Invention In digital video signal processing circuits, even if the signal processing methods are completely different, for example, the same latch circuit and addition/subtraction circuit may be used.In the present invention, as described above, this digital signal processing circuit By taking advantage of the characteristics of , the number of gates in the entire system can be reduced by selecting even a small number of common parts (for example, two or more in the case of latches) through switching, resulting in stable performance and
This allows cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a signal switching device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a specific example of FIG. 1, and FIG. 3 is a block diagram of a conventional signal switching device. 2...State I passing circuit, 3...State ■
passing circuit. 4.14, 15.18...Switch circuit, e.
...State 1 passing circuit excluding the first series circuit, 7...
...State excluding the first series circuit ■ Pass circuit, 12 River... First series circuit, 12'... State 1 First series circuit in the pass circuit, 12'... ...Condition■First series circuit in the pass circuit, 13...Second series circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] It has a first input terminal and a second input terminal, the first input terminal is connected to two different circuits A and B, and the output signal of the circuit A and the signal from the second input terminal are input. A first switch is provided that outputs one of the output terminals of the first switch, and a second switch is provided that inputs the output signal of circuit B and the signal from the second input terminal and outputs one of the signals. At the output end of the second switch are circuits C_1 and C_ of the same configuration.
A third switch and a fourth switch are provided, respectively, which input the output signal of the circuit C_1 and the output signal of the circuit C_2, and in the first state, the first switch receives the output signal from the circuit A. , the second switch receives the output signal from the second input terminal, the third switch receives the output signal from the circuit C_1, and the fourth switch receives the output signal from the circuit C_2, and in the second state. The first switch receives the output signal from the second input terminal, the second switch receives the output signal from circuit B, the third switch receives the output signal from circuit C_2, and the fourth switch receives the output signal from circuit C_1. A signal switching device configured to accept each output signal.