JPS58117726A - Signal switching circuit - Google Patents

Abstract

PURPOSE:To switch for kinds of signals with simple constitution, by using a pulse having a pulse width a half the period of pulse and another pulse shifting the pulse by 1/4 period. CONSTITUTION:Four kinds of signals e,f,g,h are inputted to two-signal switching devices 12, 13 for each two signals (e,f, and g,h), and one signal is selected at a two-signal switching device 15 out of two signals j,k selected from the four signals. The timing of switching is executed at each 1/4 period, because the input pulse has the pulse width of 1/2 period and 90 deg. phase-shift is performed (1/4 period). For example, at the first 1/4 period, the e,g are selected as the signals j,k(i=1) and the k(i.e. g) is selected at an output 10(l=0). At the 2nd 1/4 period, the j(i.e., e) is selected (l=1). At the 3rd 1/4 period, the f,h are selected as the j,k(i=0) and the j(i.e., f) is selected as the output 10(l=1). At the final 1/4 period, the k(i.e., h) is selected (l=0).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a signal switching circuit that can be used to sequentially switch and extract signals from four circuit systems to create a combined waveform.

To create a composite waveform by sequentially switching and extracting signals from four circuit systems as described above, generally the switching pulses are changed by 90 degrees to generate the signals using the configuration shown in Figure 1. A method of sequential switching was adopted. This conventional example will be briefly explained below.

First, in Figure 1, four different signals are input to input terminal 1.
, 2, 3, and 4, and are switched by the switch 9 using pulses a, b, c, and d shown in FIG. To do this, four switching pulses a to d must be set at 1 pulse period.
The switching device 9 uses pulses with a pulse width of /4 and makes the phases different by 90 degrees so that they do not overlap with each other.
must be given to Creating such a pulse requires a complex circuit and cannot be said to be easy.

The present invention eliminates the above problem and allows four types of signals to be sequentially switched using a pulse having a pulse width of 1/2 of the period of the pulse as a pulse for switching the signal. An embodiment of the present invention will be described below with reference to FIGS. 3 to 5.

4 e to the input terminals 1.2 and 3.4 in FIG. 3, respectively.
Four types of signals such as r f r g + h are given to the terminal 11, and the duty is 6o% as shown in Fig. 4.
Assume that a switching pulse of is applied. Terminals 1.2, 3.4
The input signals e and f are input to the switch 12.
Input signals g and h are switched in a switch 13 by each pulse i. For example, switch 1
2, during the period when the switching pulse i is "H", the input signal e from the terminal 1 is output, and ! 1L” period, the input signal f from the terminal 2 is output. That is, the input signal f from the terminal 2 is output.
The output of 2 will be as shown in jA in Figure 4. Similarly, in the switching device 13, when the switching pulse i is "H", the input signal from the terminal 4 is outputted, and when the switching pulse i is "L", the input signal g from the terminal 3 is outputted. Therefore, switch 1
The output of 3 is as shown in k in Fig. 4.

Furthermore, the outputs of the switches 12 and 13 are applied to the switch 15. Here, the pulse for switching the waveforms j and k by the switch 15 is the pulse i applied to the terminal 11 whose phase is shifted by 90 degrees by the phase shifter 14. This pulse
Shown in Figure 1. During this period when pulse 1 is “H”, switch 1
The output of 5 becomes the output j of the switch 12, and becomes the output of the switch 13 during the "L"' period. Therefore, as the output of the switch 15, the outputs of the switches 12 and 13 are alternately switched, resulting in the input signals e and f.

An output (m in FIG. 4) obtained by sequentially switching g and h is obtained.

A specific example of the circuit shown in FIG. 3 is shown in FIG. Similarly to Figure 3, apply four types of signals to input terminals 1, 2, 3.4, and
Let us consider the case where a switching pulse with a duty of 50% is applied to 1. When the level of this switching pulse is higher than the voltage determined by the division ratio of resistor 37.38, transistor 17.19 is turned on, transistors 16 and 20 are turned off, and the signal applied to input terminal 1 is applied to the base of transistor 30. join. At the same time, transistors 23 and 25 are also turned off.
It enters the N state and the signal applied to the input terminal 4 is applied to the base of the transistor 330. On the other hand, if the level of the switching pulse is lower than the voltage determined by the division ratio of the resistor 37.38, conversely, transistors 16 and 20°22.27 are in the ON state, transistors 17 and 19°23.25 are in the OFF' state, and the input The signals applied to terminals 2 and 3 are transmitted to transistor 30.
．． Each will be added to 33 bases. Therefore, the signals applied to the input terminals 1 and 2 are applied to the base of the transistor 30, and the signals applied to the input terminals 4 and 3 are applied to the base of the transistor 33 alternately by the switching pulses applied to the respective terminals 11. join. However, during the period in which the signal applied to input terminal 1 is applied to the base of transistor 3o, the signal applied to input terminal 4 is applied to the base of transistor 33, and the signal applied to input terminal 2 is applied to the base of transistor 3o. In the period when it is added to the base, input terminal 3
The signal applied to is applied to the base of transistor 33.

Now, the phase of the switching pulse applied to the terminal 11 is shifted by 90 degrees at the phase shifter 14, and the pulse level of this pulse is shifted by the resistor 42.
．． When the voltage is higher than the voltage determined by the division ratio of 43, transistors 29 and 31 are turned on, transistors 28 and 32 are turned off, and the signal applied to the base of transistor 3o is output to terminal 1°. That is, in the first half of this period, the signal applied to input terminal 1 is output, and in the second half, the signal applied to input terminal 2 is output. On the other hand, phase shifter 1
If the level of the pulse passing through 4 is lower than the voltage determined by the division ratio of resistors 42 and 43, transistors 28 and 32 are turned on, transistors 29 and 31 are turned off, and the signal applied to the base of transistor 33 is transferred to terminal 1.
Output to 0. That is, in the first half of this period, the signal applied to the input terminal 3 is output, and in the second half, the signal applied to the input terminal 4 is output. Therefore, the four types of signals applied to the input terminals 1, 2, 3, and 4 are sequentially switched and outputted to the terminal 10.

As described above, according to the present invention, the switching pulse used for signal switching may have a duty of 5Q%, and with this switching pulse, four types of signals can be sequentially switched every 1/4 of the period of the switching pulse. This facilitates circuit configuration.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional example in which four signals can be switched sequentially.
Fig. 2 is a waveform diagram for explaining the operation of Fig. 1, Fig. 3 is a block diagram of a signal switching port-path according to an embodiment of the present invention, and Fig. 4 is a waveform diagram of each part for explaining the operation of Fig. 3. FIG. 6 is a circuit diagram showing a specific example of FIG. 3. 1.2,3,4...signal input terminal, 11...
...Switching pulse input terminal, 1o...Output terminal, 12.13.15...2 signal switch, 14.
...90 degree phase shifter, 16-33...transistor, 34-46...resistor.

Claims (1)

[Claims] Adding two signals of four types to a first two-signal switch and a second two-signal switch, and switching the signals applied to the two two-signal switch by a switching pulse with a duty of 50%, By adding these outputs to the third 2-signal switch and switching the signals using the above-mentioned switching pulse shifted by 90 degrees, 4 types of signals can be output from the 3rd 2-signal switch with the period of the switching pulse. A signal switching circuit that sequentially switches and outputs every 1/4 of the signal.