JPH11355002A - Signal combiner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signal combiner which suppresses a power loss even if signals are not combined and which does not adversely affect the outputted signal. SOLUTION: The signal combiner is provided with a first change-over switch 21 which is connected to the poststage of a first signal input terminal and changes over two outputs to one side and a second change-over switch 22 which is connected to the preceding stage of a signal output terminal and changes over two inputs to one side. A power distribution combiner 10 to which a second signal is inputted when the signals are not combined is made to be a bypass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a signal synthesizer for synthesizing an analog signal, especially a high-frequency analog signal.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a basic configuration of a signal synthesizer of this kind. In FIG. 2, reference numeral 1 denotes a first signal input terminal for inputting a first signal to be synthesized, 2 denotes a second signal input terminal for inputting a second signal to be synthesized, and 3 denotes a first signal and a second signal. An output terminal 10 from which a signal obtained by combining the above signals is output is a power distribution combiner that combines the powers input to the terminals 1 and 2 and outputs the combined power from a terminal 3.

In the signal combiner shown in FIG. 2, the second signal is always combined with the first signal. However, when there is a case where the first signal is used without combining the signals, the signal shown in FIG.
As shown in the figure, the second signal input terminal 2 and the power distribution combiner 1
0 between terminal 2 of SPST (single-pole single-th
row) The switch 20 is provided, and the switch 20 is operated to turn on / off the second signal input.

[0004]

The conventional signal combiner of this type is constructed and operates as described above. However, in the combiner shown in FIG. 3, the power loss of the circuit increases when no signal is combined. There is also a problem that a signal output from the output terminal 3 is subjected to amplitude modulation due to impedance mismatch. That is, when the SPST switch 20 is turned off and the first signal is input from the first signal input terminal 1, the input signal is output to the terminals 2 and 3 of the power distribution combiner 10 by ず つ each, The signal output from terminal 2 is S
The signal is reflected by the PST switch 20 and is again input from the terminal 2 to the power distribution / combiner 10. However, since this signal flows through the terminals 1 and 3, the power loss increases, and this signal and the first signal Has an adverse effect on the first signal, such as that the impedance of the first signal is modulated because the impedances do not match.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a signal synthesizer which suppresses power loss even when signals are not synthesized and does not adversely affect an output signal. The purpose is.

[0006]

A signal combiner according to the present invention is connected to a stage subsequent to a first signal input terminal and switches between two outputs, and is connected to a stage preceding a signal output terminal. A second switch for switching between two inputs to one of the two, and one output of the first switch is connected to an input terminal of a two-input one-output power distribution combiner;
A second signal input terminal connected to another input terminal of the power distribution combiner, and a first line connected to an output terminal of the power distribution combiner and one input of the second switch; And a second line to which the other output of the first changeover switch and the other input of the second changeover switch are connected, and the second signal is added to the first signal. When synthesizing, the first changeover switch and the second changeover switch are connected to the first line, and the second signal is applied to the first signal.
When the signals are not combined, the first changeover switch and the second changeover switch are connected to the second line. With the signal synthesizer of the present invention having the above-described configuration, the circuit impedance can be matched whether or not the signals are combined.

Further, the first and second changeover switches are characterized in that they are constituted by SPDT (single-poledouble-throw) switches. The insertion loss of the SPDT switch is about 0.5 dB, so that the loss of the entire signal combiner can be made about 1 dB.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, 1 is a first signal input terminal for inputting a first signal to be synthesized, 2 is a second signal input terminal for inputting a second signal to be synthesized, 3 is an output terminal, and 10 is a terminal 1 And a power distribution / combiner that combines the powers input to the terminals 2 and outputs from the terminal 3. 21 is a first changeover switch, 22 is a second changeover switch, 31 is a first line, 32 is a second line, and the first changeover switch and the second changeover switch are S
It can be constituted by a PDT (single-pole double-throw) switch.

Next, the operation will be described. In FIG. 1, a first analog signal and a second analog signal are input to a first signal input terminal 1 and a second signal input terminal 2, respectively, and the input signals are power-synthesized composite signals. Are output from the output terminal 3, the changeover switches 21 and 22 are connected to the first line 31 side. That is, when each of the changeover switches 21 and 22 is connected to the first line 31 side, the first signal input from the first signal input terminal 1 is transmitted to the power combiner 10 through the first changeover switch 21. Input to terminal 1. Also, the second signal input terminal 2
, A second signal is input to the terminal 2 of the power distribution / synthesizer 10, and the power distribution / synthesizer 10 power-combines the signals input from the terminals 1 and 2 and outputs the resultant signal from the terminal 3; The signal is output from the output terminal 3 via the output terminal 22. At this time, the first signal input from the first signal input terminal 1
Are attenuated by the insertion loss in the changeover switches 21 and 22 and the power distribution / combination circuit 10.

Next, a case where the second signal is not synthesized will be described. When the second signals are not combined, the switches 21 and 22 are connected to the second line 32 as shown in FIG. The changeover switches 21 and 22 are connected to the second line 32
Connected to the first line, the first signal input from the first input terminal 1 is transmitted to the first switch 21 and the second line 3.
2, output from the output terminal 3 via the second switch 22. At this time, there is no circuit in the second line 32 that greatly attenuates the signal, and the first line 31 and the second line
Can be made independent of the line 32, and the circuit impedance can be matched in either line. Therefore, the signal input to the first input terminal 1 is
It is possible to output from the output terminal 3 only by insertion loss due to 1 and 22. Generally, the insertion loss of the SPDT switches constituting the changeover switches 21 and 22 is about 0.5 dB, so that the loss of the entire signal combiner can be reduced to about 1 dB. In addition, since no impedance mismatch occurs, it is possible to prevent inconveniences such as modulation of the output signal.

[0011]

As described above, the signal combiner of the present invention has the effects of reducing power loss when signals are not combined, and capable of preventing impedance mismatch and outputting an accurate signal. is there.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a basic configuration of this type of signal synthesizer.

FIG. 3 is a block diagram showing an example of this type of conventional signal synthesizer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st signal input terminal 2 2nd signal input terminal 3 output terminal 10 power distribution synthesizer 21 1st changeover switch 22 2nd changeover switch 31 1st line 32 2nd line

Claims (2)

[Claims] A first signal input terminal connected to a stage subsequent to the first signal input terminal;
A first changeover switch for switching between the outputs, a second changeover switch connected to the preceding stage of the signal output terminal to change between two inputs, and one output of the first changeover switch has two inputs and one output Is connected to an input terminal of the power distribution combiner, and a second signal input terminal is connected to another input terminal of the power distribution combiner.
A first line to which an output terminal of the power distribution combiner is connected to one input of the second switch; another output of the first switch and the second switch; And a second line connected to the other input of the first signal. When the second signal is combined with the first signal, the first switch and the second switch are connected to the first signal. Signal combining characterized in that, when the second signal is not combined with the first signal, the first switch and the second switch are connected to the second line. vessel. 2. The signal synthesizer according to claim 1, wherein the first switch and the second switch are S
A signal combiner comprising a PDT (single-pole double-throw) switch.