JPH1082803A - Digital storage oscilloscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-channel oscilloscope by providing a terminal having the sampling clock in common, a terminal having the trigger signal in common, and a control interface terminal, and connecting them by cables. SOLUTION: The input signal is fed from a terminal 4, it passes through an attenuator, a preamplifier 7, and an A/D-converter 8, and the wave-form data are stored in a memory 9 and displayed on an indicator by a display circuit 12. The trigger signal is fed to a time base 11 from a trigger circuit 15 to control the timing of ADD-conversion, and a switch S1 is provided to cut off the internal trigger signal and use the external trigger signal. One of clock generating circuits 20 is used by a switch s2, and oscilloscopes 1, 2 are synchronously operated. The control signal and wave-form data of a control panel 3 are mutually communicated by an interface 21 from a data bus through an interface circuit 14, the oscilloscope 1 controls the oscilloscope 2 and picks up and displays its wave-form data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a circuit for connecting a plurality of digital storage oscilloscopes (DSOs).

[0002]

2. Description of the Related Art The number of input channels of a DSO is mainly two or four. In computer-controlled electronic equipment, there are cases where it is desired to view many control signals at one time. In such a case, four or more input signals are required. DSO for number of channels
Is required. However, if you purchase an 8 channel DSO, 2 channels is enough for normal use,
In normal use, 8 channels are useless. For example, assuming that there are two 4-channel input DSOs, if they can be used in synchronization by connecting them with a cable, it is possible to increase the number of channels only when necessary.

In the prior art, for example, as shown in FIG. 5, if there is an external sample clock input terminal 30, a sample clock output terminal 29, a trigger signal output terminal 33, a control bus 31 such as GPIB, and a computer 27, realizable. However, to completely synchronize the two DSOs 26, the clock output terminal 29 and the clock input terminal 30 are connected by a cable 32, and one of the trigger signal output terminals 3 is used to synchronize with a trigger signal of an arbitrary channel.
3 must be connected to the other external trigger input terminal 28. The computer is indispensable because the displays of the two DSOs are displayed on the same screen, and the settings such as the time range and the trigger mode are collectively performed.

[0004]

The above-mentioned prior art includes the following:
Since a control computer is required, and the shape of the digital oscilloscope itself is large, the setting becomes large, and there is a disadvantage that it is not possible to easily increase the number of channels.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital oscilloscope which eliminates these drawbacks and can easily realize a multi-channel input oscilloscope by connecting a plurality of oscilloscopes.

[0006]

According to the present invention, in order to achieve the above object, a DSO is provided with a terminal for sharing a sampling clock, a terminal for sharing a trigger signal, and a signal interface terminal for control, and these are connected by a cable. This function adds a function to transfer and display the acquired waveform by simply performing the operation and to control various settings from the first DSO (master) to the second and subsequent DSOs (slaves).

As a result, a DSO having this control terminal
Can be used as a multi-channel DSO simply by connecting them with a cable.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings.

In this embodiment, a portable, for example, a notebook type DSO using a liquid crystal display is provided with a terminal for sharing a sampling clock, a terminal for sharing a trigger signal, and a signal interface terminal for control. is there.

This will be described with reference to FIGS. 1 and 2.

FIG. 1 shows two notebook type DSOs having a two-channel input and an external trigger input.
The example in the case of using as SO is shown. Two DS
The display unit is opened and the lower unit is closed when O is overlapped, and the two units are connected by an interface cable on the rear surface. The upper DSO1 siphons the waveform data of the lower DSO2 and displays it on the same screen as the waveform of the DSO1. The measurement settings can also be controlled from the control panel of the DSO 1 through the interface cable 6, and the DSO 2 does not need to be open.

FIG. 2 is a block diagram showing the inside of the embodiment in a state where the two units are connected. The input signal enters the AD converter 8 from the terminal 4 via the attenuator and the preamplifier 7. The AD-converted waveform data is temporarily stored in the memory 9 and is displayed on the display circuit 12 under the control of the microcomputer 13.
And is displayed on the display 5. On the other hand, the trigger signal passes through the trigger selector and the comparator 15 and the time base 1
The switch S1 is provided here to turn off the internal trigger signal and enable triggering with an external signal. Since DSO1 is the controlling side, the switch S1 is on the contact 17 side, and the DSO2 is on the contact 16 side for sending a trigger signal to the DSO1 via the signal line 23 in the interface cable.
Since the two DSOs need to operate synchronously, the clock generator uses either clock signal. For this reason, the switch S2 is provided, and since the DSO1 itself is the master clock output side, the clock is sent out to the contact 18 via the signal line 22 to the outside, and the switch S2 is set to the contact 19 to receive the clock. Control signals and waveform display data of the control panel are transmitted from the data bus via the interface circuit 14 to the interface bus 21.
In this case, the DSO 1 controls the DSO 2 to download and display the waveform data. When high-speed refresh of waveform display is required, the interface bus 21 requires special specifications with a high data transfer speed. If not particularly necessary, an interface using general serial communication such as RS-232C may be used.

FIGS. 3 and 4 show display examples of the DSO1. FIG. 3 shows a waveform display when two channels are input in a normal use state. Numeral 24 displayed on the left end of the waveform indicates the channel number and ground level position of the waveform. FIG. 4 is a display example of DSO1 in FIG. 1 in an operating state in which two DSOs are connected, and a waveform of the connected DSO2 is additionally displayed. Since the control panel 3 can control only two channels, in this case, the control is currently inactive or active depending on whether it is displayed lightly (shown by a dotted line) like a numeral 25 or darkly (shown by a solid line) like a numeral 24. Indicates a channel.

When this embodiment is applied, a slave-dedicated DSO 34 which does not have a display unit as shown in FIG. 6 and has only a control panel without a control panel can be considered. This can reduce the cost of the display unit and is economical when it is desired to expand only the number of channels.

[0015]

According to the present invention, when a multi-channel input is not required, it can be used as a simple 2 to 4 channel DSO. When necessary, a plurality of DSOs having the interface of the present invention can be prepared. In addition, a multi-channel oscilloscope can be realized. This economic effect is great,
For example, if an 8-channel DSO is purchased because an 8-channel input is required, a channel occupied by one person and not used in a normal use state of one or two channels is wasted. If, for example, four 2-channel DSOs having the interface of the present invention are purchased, there are usually four 2-channel DSOs, and four people can work separately. There is little waste if four units are combined and used as an 8-channel DSO when necessary.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an embodiment showing a use state of the present invention.

FIG. 2 is a block diagram showing the inside of the embodiment of FIG. 1;

FIG. 3 is a display screen diagram when one unit is operated independently in a display example of a use state of the present invention.

FIG. 4 is a diagram of a display screen when two devices are connected in a usage state display example of the present invention.

FIG. 5 is a connection diagram showing an example in which two conventional DSOs are connected.

FIG. 6 is an external perspective view of an embodiment of an input-only machine without a display unit.

[Explanation of symbols]

1: master DSO, 2: slave DSO, 3: control panel, 4: input connector, 5: display panel, 6:
Interface cable, 7: attenuator and preamplifier, 8: AD converter, 9: memory, 10: sample clock, 11: time base, 12: display circuit, 13: microcomputer, 14: interface, 15: trigger signal generation circuit, 20: clock generation circuit, 21: external control interface bus, 22: external clock line, 2
3: external trigger signal line, S1: external / internal trigger switch, S2: external / internal clock switch, 26: DSO, 27: control computer, 28:
External trigger input terminal, 29: clock output terminal, 30:
Clock input terminal, 31: control bus, 32: cable,
33: trigger signal output terminal.

Claims (2)

[Claims] 1. A digital storage oscilloscope, comprising: an external trigger pulse input terminal; a switch for selecting either a trigger pulse signal of an internal trigger circuit or a trigger pulse signal input from the external trigger pulse input terminal; A clock input terminal, a switch for selecting either a internally generated sample clock or a clock signal input from the external sample clock input terminal, and an interface terminal for communicating waveform data and control data with an external device are provided. A digital storage oscilloscope. 2. The digital storage oscilloscope according to claim 1, wherein said plurality of digital storage oscilloscopes are connected to said three input terminals, respectively.
Control other slave digital storage oscilloscopes from one master digital storage oscilloscope,
A digital storage oscilloscope for receiving and displaying data.