JPH03189567A - Electric waveform measuring instrument - Google Patents

Abstract

PURPOSE:To generate sufficient brightness on a fluorescent screen by composing the electron source of a CRT for an oscilloscope by using a light source and a photoelectric surface which emits photoelectrons by being irradiated by the light source. CONSTITUTION:A measuring instrument 11 which uses the CRT 10 for the oscilloscope has its electron source 16 composed of the light source 12 and the photoelectric surface 14 which emits photoelectrons by being irradiated by the light source 12. The light source 12 is a short-pulse light laser diode and is controlled through a driving circuit 30 with the trigger signal from a trigger generating circuit 28. This instrument is so constituted that the timing of the sweep voltage applied from a deflecting circuit 32 to a horizontal deflecting plate 24, the timing of the voltage applied from an electric signal source 31 to be measured which is amplified 29 to a vertical deflecting plate 22, and the light source 12 synchronize with one another. Thus, photoelectrons are emitted according to the quantity of light which is made incident on the photoelectric surface 14. Accordingly, the light from the light source 12 is increased in intensity to emit photoelectrons from the photoelectric surface 14 by a sufficient amount, and a large current is obtained in a short time.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an electrical waveform measuring device for observing electrical signals.

[Conventional technology]

In an oscilloscope for observing electrical signals,
Conventionally, a thermionic source is used to heat the cathode. [Problem to be Solved by the Invention 1] As mentioned above, since the oscilloscope uses a thermionic source, the instantaneous amount of current is small, and when the oscilloscope is operated at high speed, there is a problem that the brightness on the fluorescent screen is insufficient. be. Conventionally, this problem has been solved by inserting a microchannel plate just in front of the phosphor screen to multiply the electrons, but this has the problem of complicating the structure and operation. This invention was made in view of the above-mentioned conventional problems, and includes an electron source, a deflection electrode that deflects electrons from the electron source,
An object of the present invention is to provide an electrical waveform measuring device including a phosphor screen that can obtain sufficient brightness on the phosphor screen.

[Means for Solving the Problems] The present invention provides an electrical waveform measuring device using a CR for an oscilloscope, which includes an electron source, a deflection electrode for deflecting electrons from the electron source, and a signal output section. The above object is achieved by constructing the electron source from a photocathode that emits photoelectrons when irradiated with a light source. Further, the above object is achieved by turning on and off the light source in synchronization with the sweep voltage at the deflection electrode. Further, an electron source is constituted by a photocathode in the streak tube and an optical a device for irradiating the same, and an electrical signal to be measured is applied to one set of deflection electrodes among the two sets of deflection electrodes of the streak tube. The above object is achieved by providing a circuit to apply a sweep voltage to each of the other sets of deflection electrodes. Further, the above object is achieved by turning on and off the light source in synchronization with the sweep voltage. Further, the above object is achieved by making at least one set of the two sets of deflection electrodes a traveling wave type deflection electrode. Furthermore, the light source device can be freely switched between an irradiation light source that irradiates the photocathode as an electron source and a light source of the light to be measured,
Further, the above object is achieved by causing the circuit to switch and apply an electrical signal to be measured and a streak deflection voltage to the deflection electrode in synchronization with switching of the light source. Further, a memory for storing the output for the signal under test and the output for the light to be measured, and a display means for correcting and displaying a timing difference and a time axis scale between the electrical signal output and the optical signal output based on the memory. The above problem is achieved by providing the following. [Function] In this invention, the electron source in the CRT for an oscilloscope is composed of a light source and a photocathode that emits photoelectrons when irradiated by the light source.
By increasing the intensity of the light from the light source, a sufficient amount of photoelectrons can be emitted from the photocathode, and the brightness of the phosphor screen can be increased without providing a microchannel plate. Further, in the second invention, an electron source is configured from a photocathode in a streak tube and a light source device for irradiating the photocathode, and an electric signal to be measured is applied to one set of deflection electrodes of the streak tube, and an electric signal to be measured is applied to one set of deflection electrodes of the streak tube. Since a sweep voltage was applied to each electrode, the electrical waveform could be measured using a streak tube. Furthermore, by switching the deflection voltage applied to the deflection electrode, optical signals can also be measured as a normal streak tube.

Example 1 An example of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, which shows an electrical waveform measuring device 11 (
(whole illustration omitted), an electron source 16 is constituted by a light source 12 and a photocathode 14 that emits photoelectrons when irradiated with the light source. Reference numeral 18 in FIG. 1 denotes a glass face plate on which the photocathode 14 is formed, 20 an electron lens forming an electron gun together with the photocathode 14, 22 a vertical deflection plate, 24 a horizontal deflection plate, 26 a fluorescent screen, 28 is a trigger generation circuit, 29 is an amplifier, 30 is a laser diode drive circuit, 31 is an electrical signal source to be measured,
32 indicates a deflection circuit, respectively. The light source 12 is a short pulse light laser diode,
It is controlled via a laser diode drive circuit 30 based on a trigger signal from a trigger generation circuit 28. Also, based on the trigger signal output from the generation circuit 28, the timing of the sweep voltage applied from the deflection circuit 32 to the horizontal deflection plate 24 and the voltage from the electrical signal source 31 to be measured amplified by the amplification 33 are determined. The timing of application to the vertical deflection plate 22 and the light source 12 are all configured to be synchronized. Next, the operation of the first embodiment will be explained. In the CRTIO for an oscilloscope, when the electron source 16 is configured from the light source 12 and the photocathode 14 as described above,
Basically, photoelectrons are emitted from the photocathode 14 depending on m of light incident on the photocathode 14. Therefore, by increasing the intensity of the light from the light ti, 12, a sufficient amount of photoelectrons can be emitted from the photocathode 14. Therefore, there is no need to provide a microchannel plate to multiply the amount of photoelectrons incident on the phosphor screen 26, as in conventional oscilloscope CRTs. Further, if a short pulse light source is used as the light source 12 as in the first embodiment, a particularly large current can be obtained in a short period of time during high-speed sweeping. Usually short pulse light has a very high peak power compared to OC light, and furthermore, the photocathode 14 has a very fast response characteristic of 1 oors or less.
A large current can be obtained in a short period of time by injecting the above-mentioned short pulse light having a high peak power into 4. Such an instantaneous large current cannot be obtained with a thermionic source in a conventional CRT for an oscilloscope. Furthermore, in the above embodiment, since the light source 12 is constituted by a short-pulse laser diode driven by the laser diode drive circuit 30, it can be easily modulated by an electric signal from the laser diode drive circuit 30, and the light source 12 can be easily modulated by an electric signal from the laser diode drive circuit 30.・By turning off, blanking is possible, and it can be easily applied to high repetition operations. Although the first embodiment described above uses a short pulse laser diode as the light source 12, a mode-locked YA laser diode is used as the light source 12.
Other types of pulsed lasers such as G lasers or regular DC light sources may also be used. Furthermore, although the first embodiment uses the phosphor screen 26 as the signal output section, other signal output sections such as an electronically implanted CCD or the like may be used instead. Next, a second embodiment of the present invention shown in FIG. 2 will be described. In this second embodiment, the present invention is applied to a streak camera to construct an electrical waveform measuring device 33 that also serves as a streak camera. That is, an electron source 40 is constituted by the photocathode 36 in the streak tube 34 and the optical device 38 that irradiates it, and the electrical signal to be measured is applied to the vertical deflection plate 42 of the two sets of deflection electrodes of the streak tube 34. A circuit 46 for applying a sweep voltage to the other horizontal deflection plate 44 is provided. The streak tube 34 includes, in order from the photocathode 36 side, an electron lens 48, the vertical deflection plate 42, the horizontal deflection plate 44,
Microchannel plate (hereinafter referred to as MCP) 50
and a fluorescent screen 52 which is an output surface. An output optical system 54, a TV camera 56, and a computer 58 for processing and storing output signals of the TV camera 56 are arranged for the phosphor screen 52. The light source device @38 includes an input optical system 59, a slit 60, and an incident light switching device 6 arranged in this order from the photocathode 36 side.
2. It is composed of a short pulse light laser diode 64 and a laser diode drive circuit 66 for driving the short pulse light laser diode 64. The incident light switching device 62, as shown in FIG.
A beam splitter 62A disposed on the optical path from the short pulse laser diode 64 to the photocathode 36, a shutter 628 disposed between the beam splitter 62A and the short pulse laser diode 64, and a beam splitter 62A. A shutter 620 is arranged on the optical path to allow the light to be measured to enter from the side. The circuit 46 includes an amplifier 46A for amplifying the electrical signal to be measured from the electrical signal source 70 to be measured;
Trigger generation circuit 46E that generates a trigger signal from the output of 6A and outputs it to the laser diode drive circuit 66 and deflection circuit 46B, and a deflection circuit 46 that outputs a deflection voltage based on the trigger signal from this trigger generation circuit 46E.
B, the shift voltage generation circuit 46C, and the amplifier 46A are connected to the electrical signal source to be measured 70 or the streak trigger circuit 72h1.
and correspondingly, the vertical deflection plate 42 is selectively connected to the amplifier 46A and the deflection circuit 46B, and at the same time, the horizontal deflection plate 44 is connected to the deflection circuit 46B.
B and a switching circuit 46D for selectively connecting to the shift voltage generating circuit 46C. This FJJ replacement circuit 46D also includes the signal source under test 70.
When measuring the electrical signal to be measured, the shutter 62G in the incident light switching device is closed and the shutter 62B is opened, and conversely, when used as a streak camera, the shutter 620 is switched.
62B is opened and 62B is closed. Next, the operation of the second embodiment will be explained. First, when measuring an electrical signal, the switching circuit 46D switches the amplifier 46A to the electrical signal source 70 to be measured, the vertical deflection plate 42 to the amplifier 46A, and the horizontal deflection plate 44 to the deflection circuit 46B. 62G
Close the shutter 62G, open the laser diode 6
4 is switched so that the short pulse light from 4 is incident on the streak tube 34. In this way, the electrical signal from the electrical signal source to be measured 70 is amplified by the amplifier 46A, and then the vertical deflection plate 42
At the same time, a sweep voltage from the deflection circuit 46B is applied to the horizontal deflection plate 44 from the amplifier 46A via the trigger generation circuit 46E. At this time, when the short pulse light laser diode 64 is excited by the laser diode drive circuit 66 in synchronization with the trigger signal from the trigger generation circuit 46E, the short pulse light laser diode 64 emits light only when necessary. The short pulse light is transmitted through the shutter 62B and the beam splitter 6.
2A, the photocathode 3 via the slit 60 and the input optical system 59.
6, where photoelectrons are generated. These photoelectrons are accelerated and focused by the electron lens 48, and then pass through the vertical deflection plate 42 and the horizontal deflection plate 44 to the MCP 50.
The signal is multiplied by the phosphor screen 52, which is the output screen, and output as a waveform. Through the above operations, photoelectrons vertically deflected according to the electrical signal to be measured pass through the MCP 50 and form an output waveform on the phosphor screen 52, which is input to the computer via the TV camera 56, where it is processed and stored. will be done. Next, the case of measuring an optical signal will be explained. In this case, the switching circuit 46D shifts the amplifier 46A to the streak trigger circuit 72, the vertical deflection plate 42 to the deflection circuit 46B, and the horizontal deflection plate 44 to the voltage generation circuit 46.
At the same time, the shutter 62B is closed and the shutter 620 is opened in the incident light switching device 62. Therefore, the light to be measured passes through the shutter 6201, the beam splitter 62A1, the slit 60, and the input optical system 58, and enters the photocathode 36, where photoelectrons are generated. These photoelectrons are accelerated and focused by the electron lens 48, and then pass through the vertical deflection plate 42 and the horizontal deflection plate 44 to the MCP 50.
The same voltage as in a normal streak tube is applied to the vertical and horizontal deflection plates 42 and 44 which form a streak image on the phosphor screen 52 which is the output surface. That is, the trigger signal from the streak trigger circuit 72 is
It is input to the trigger generation circuit 46E via the amplifier 46A,
Based on the trigger signal from the trigger generation circuit 46E, a streak sweep voltage is applied from the deflection circuit 46B to the vertical deflection plate 42, and at the same time, a shift voltage is applied from the shift voltage generation circuit 46C to the horizontal deflection plate 44. A streak image obtained by sweeping the fluorescent screen 52 through the above-described operation is read out by the TV camera 56, subjected to signal processing in the computer 58, and stored. Here, if the timing difference between the light to be measured and the streak trigger signal and the timing difference between the electrical signal to be measured and the streak trigger signal are detected in advance, the relationship between the light to be measured and the electrical signal to be measured on the time axis can be detected. By correcting this using the computer 58, the respective output images of the light to be measured and the electrical signal to be measured can be output on the same screen. This makes it possible to measure the correlation between electrical waveforms and light with unprecedentedly high time resolution. Furthermore, when measuring an electrical signal, if the short pulse light laser diode 64 is excited by the laser diode drive circuit 66 as described above in synchronization with the signal from the trigger generation circuit 46E, the laser light can be efficiently emitted only when necessary. Not only can it be obtained, but blanking is also possible without special sweeps. In the above embodiment, a short pulse laser diode 64 is used as a light source when measuring electrical signals, but the present invention is not limited to this.
Other pulse lasers such as a G laser or a DC light source may also be used. Furthermore, the incident light switching device 62 is not limited to the embodiment shown in FIG. 3, and may have other configurations. Further, in the above embodiment, the electrical signal to be measured is applied to the vertical deflection plate 42, which has a numerically high deflection sensitivity, but it may be applied to the horizontal deflection plate 44. Further, in the above embodiment, the MCP 50 is arranged in front of the phosphor screen 52 which is the output source, but the MCP 50 does not necessarily need to be provided. Further, the phosphor screen 52 may be combined with an image intensifier, or an electronically implanted COD or the like may be placed in place of the phosphor screen 52. Further, in the above embodiment, the deflection plate is a normal deflection plate, but it can be replaced with a meander-type traveling wave deflection plate 74A as shown in FIG. 4, or a shielding spiral as shown in FIG. It is also possible to use a type traveling wave deflection plate 74B, a parallel spiral type traveling wave deflection plate 74C as shown in FIG. 6, and a lumped constant type traveling wave deflection plate 74D as shown in FIG. When a traveling wave type deflection plate is used in this way, the band of the deflection plate is greatly improved. Therefore, if the deflection electrode to which the deflection voltage is applied has a traveling waveform, a high-speed deflection voltage can be applied, and higher-speed sweeping becomes possible. Furthermore, when measuring an electrical signal, if the deflection electrode to which this signal is applied is of a traveling wave type, the electrical signal can be measured in a higher band. [Effects of the Invention] Since the present invention is configured as described above, it has an excellent effect in that sufficient brightness can be obtained on the output surface without using an MCP or the like. In addition, it has the excellent effect of being able to measure optical signals as well as electrical signals using the same device as a streak tube.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view including a partial circuit diagram showing a first embodiment of an electrical waveform measuring device according to the present invention, and FIG. 2 is a schematic cross-sectional view including a partial circuit diagram showing a second embodiment of the present invention. 3 is an enlarged block diagram showing the incident light switching device in the second embodiment, and FIGS. 4 to 6 are plan views and sectional views showing modifications of the deflection plate in the same embodiment. , FIG. 7 is a plan view of the same. 10...CRT for oscilloscope. 11.33... Electric waveform measuring device, 12... Light source, 14.36... Photocathode, 16.40... Electron source, 22.42... Vertical deflection plate, 24.44...・Horizontal deflection plate, 26.52... Fluorescent screen, 31.70... Electric signal source to be measured, 32... Deflection circuit, 34... Streak tube, 38... Light source device, 46... -Circuit, 46A...Amplifier, 46B...Deflection circuit, 46C...Shift voltage generation circuit, 46D...Switching circuit, 58...Computer, 62...Incoming light switching device, 64...・Short pulse light laser diode, Fig. 72... Streak trigger circuit, 74A to 74D... Traveling wave type deflection plate.

Claims (7)

[Claims] (1) An electron source, a deflection electrode that deflects electrons from the electron source,
and an electrical waveform measuring device using a CRT for an oscilloscope having a signal output section, characterized in that the electron source is constituted by a light source and a photocathode that emits photoelectrons when irradiated by the light source. Electric waveform measurement device. (2) The electrical waveform measuring device according to claim 1, wherein the light source is turned on and off in synchronization with a sweep voltage at the deflection electrode. (3) An electron source is constructed from a photocathode in a streak tube and a light source device that irradiates the photocathode, and an electrical signal to be measured is applied to one set of deflection electrodes among the two sets of deflection electrodes of the streak tube. An electrical waveform measuring device comprising a circuit for applying a sweep voltage to each set of deflection electrodes. (4) The electrical waveform measuring device according to claim 3, wherein the light source is turned on and off in synchronization with the sweep voltage. (5) The electrical waveform measuring device according to claim 3 or 4, wherein at least one set of the two sets of deflection electrodes is a traveling wave type deflection electrode. (6) In claim 3, 4 or 5, the light source device:
The light source can be freely switched between an irradiation light source that irradiates the photocathode as an electron source and a light source that emits the light to be measured, and the circuit is configured to apply the light to be measured to the deflection electrode in synchronization with the switching of the light source. An electrical waveform measuring device characterized in that an electrical signal and a streak deflection voltage are switched and applied. (7) In claim 6, a memory that stores an output for the signal under test and an output for the light under test;
An electrical waveform measuring device comprising display means for correcting and displaying the timing difference and time axis scale between the electrical signal output and the optical signal output based on the information stored in the memory.