US2896086A - Attenuator network - Google Patents
Attenuator network Download PDFInfo
- Publication number
- US2896086A US2896086A US669149A US66914957A US2896086A US 2896086 A US2896086 A US 2896086A US 669149 A US669149 A US 669149A US 66914957 A US66914957 A US 66914957A US 2896086 A US2896086 A US 2896086A
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- Prior art keywords
- attenuator
- network
- resistance
- light
- grid
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/24—Frequency- independent attenuators
- H03H7/27—Frequency- independent attenuators comprising a photo-electric element
Definitions
- This invention relates generally to an attenuator network and more particularly to a photoresistive attenuator network.
- Attenuator networks are employed to introduce a known amount of loss when working with resistive impedances.
- attenuator networks have input and output impedances which are suitably matched to the associated source and load irnpedances It is a general object of the present invention to provide an attenuator in which the attenuation and impedance may be optically controlled.
- the photoconductive material forms the resistive elements of the attenuator network.
- Light serves to vary the resistance of portions of the photoresistive material to give the desired attenuation and terminating impedances.
- Figure 1 is a plan view of a suitable gridnetwork
- Figure 2 is a sectional view taken along the line 22 of Figure 1;
- Figure 3 is a plan view showing a light pattern striking the photoconductive material
- Figure 4 shows an attenuator in which the light is controlled by means of a filter
- Figure 5 shows a plan view of a graded light filter which may be used in Figure 4;
- Figure 6 shows an attenuator which is controlled by means of a light cam
- Figure 7 shows an attenuator which is controlled by the illumination from a pair of lights
- Figure 8 shows an attenuator in which the illumination is controlled by mechanical movement of the network
- Figure 9 is an equivalent circuit diagram of an attenuator constructed in accordance with Figures 1 and 2.
- the grid network 10 shown in Figure 1 comprises independent conductive grids 11, 12, 13 and 14 which are covered with a layer of photoconductive material, to be presently described.
- the grid 13 is interlaced with the grid 11 to form one of the optically controlled photoresistive elements of the attenuator
- the grid 12 is interlaced with the grid 13 to form another optically controlled photoresistive element
- the grid 14 is interlaced with the grid 13 to form a third photoresistive element.
- the photoresistive elements, as illustrated, are connected to form an unbalanced T attenuator.
- An equivalent circuit is shown in Figure 9 wherein the resistors 16, 17 and 18 represent the photoresistive elements which form the T network.
- Each of the photoresistive elements is indicated as being variable, corresponding to the optical variation of resistance.
- the grid network is covered with a layer of photoresistive material 15 (Figure 2) whereby adjacent grids are interconnected through the material.
- the photoresistive material may be in the form of a powder which is dispersed in a binder and applied to the surface to form a relatively thin film.
- the powder may be dispersed in a carrier and applied to the grid network and the assembly is placed in an oven and baked at a relatively high temperature to form a sintered photoconductive layer.
- the shaded area 19 represents a light beam which is impinging upon the photoconductive layer 15.
- the resistance of the layer interconnecting the grids 13 and 14 is lowered.
- the resistance 18 represents the resistance between these grids.
- the resistance 18 is considerably lowered whereby maximum attenuation is obtained in the attenuator.
- the shunt resistance 18 is raised and the series resistances 16 and 17 are lowered.
- the shunt resistance is at its maximum and the series resistances 16 and 17 are at a minimum.
- the attenuation introduced by the attenuator is at a minimum.
- the geometry of the light pattern and the grid can be varied as desired to give the desired variation in resistance between the various elements to thereby control the input and output impedance as well as the attenuation introduced.
- a light filter 21 is interposed between the light source 22 and the attenuating network 23.
- the illumination on various portions of the photoresistive material may be altered to control the resistance between the related grid elements.
- the filter 21 may be graded as shown in Figure 5 whereby a de-- sired variation of resistance with movement of the filter may be obtained.
- FIG 6 another means is shown for controlling the light incident upon the photoconductive material.
- An opaque shutter 2-6 having an optical cam 27 is moved as indicated by the arrow 28 between the light source and the material.
- an opaque bafile 29 is interposed between a pair of lights 31 and 32 which may be independently controlled.
- the intensity of the lights 31 and 32 the attenuation and impedance of the attenuator network may be controlled.
- the attenuation may be controlled by moving the attenuator network.
- the network is pivoted about the point 33.
- the illumination may be electronically controlled by controlling the motion of the filter or shutter.
- one or more lights may be arranged whereby the attenuation can be controlled by controlling the power supplied to the light, as illustrated in Figure 7.
- an attenuator in which the resistance elements are optically controlled.
- the attenuation may be electronically controlled by electronically controlling the motion of the filter or shutter, or by controlling the intensity of the lights.
- the resistance may be mechanically controlled by moving the various elements as desired.
- the resistance arms of the attenuator network may be varied in accordance with any desired function by suitably, contouring the light cam, grading the filter or choosing the shape of the light beam.
- a network comprising an interlaced grid network of conductive material, photoconductive material serv-g ing to interconnect the grids'of said network, said gridl network comprising four separate grids so disposed as to. form together with said photoconductive.material the resistive elements of a T-network, a light source, and means for controlling the light incident upon said photo-l conductive material whereby the attenuation and impedance level may be controlled as desired.
Description
July 21, 1959 WUNDERMAN 2,896,086
ATTENUATOR NETWORK FiledJuly 1, 1957 F 1 l3 E LIGHT DEAM nor/av F l E E INVENTOR.
/rw/'n Wunaerman l /5 ATTOR/VE Y5 United States Patent Ofiice 2,896,086 Patented July 21, 1 959 ATIENUATOR NETWORK Irwin Wunderman, Mountain View, Calif., assignor to Hewlett-Packard Company, Palo Alto, Calili, a corporation of California Application July 1, 1957, Serial No. 669,149
Claims. (Cl. 250-211) This invention relates generally to an attenuator network and more particularly to a photoresistive attenuator network.
As is well known, attenuator networks are employed to introduce a known amount of loss when working with resistive impedances. In general, attenuator networks have input and output impedances which are suitably matched to the associated source and load irnpedances It is a general object of the present invention to provide an attenuator in which the attenuation and impedance may be optically controlled.
It is another object of the present invention to provide an attenuator network which includes a conductive grid network having a predetermined configuration which is covered by photoconductive material. The photoconductive material forms the resistive elements of the attenuator network. Light serves to vary the resistance of portions of the photoresistive material to give the desired attenuation and terminating impedances.
These and other objects of the invention will become more clearly apparent from the following description when taken in conjunction with the accompanying drawmg.
Referring to the drawing:
Figure 1 is a plan view of a suitable gridnetwork;
Figure 2 is a sectional view taken along the line 22 of Figure 1;
Figure 3 is a plan view showing a light pattern striking the photoconductive material;
Figure 4 shows an attenuator in which the light is controlled by means of a filter;
Figure 5 shows a plan view of a graded light filter which may be used in Figure 4;
Figure 6 shows an attenuator which is controlled by means of a light cam;
Figure 7 shows an attenuator which is controlled by the illumination from a pair of lights;
Figure 8 shows an attenuator in which the illumination is controlled by mechanical movement of the network; and
Figure 9 is an equivalent circuit diagram of an attenuator constructed in accordance with Figures 1 and 2.
The grid network 10 shown in Figure 1 comprises independent conductive grids 11, 12, 13 and 14 which are covered with a layer of photoconductive material, to be presently described. The grid 13 is interlaced with the grid 11 to form one of the optically controlled photoresistive elements of the attenuator, the grid 12 is interlaced with the grid 13 to form another optically controlled photoresistive element, and the grid 14 is interlaced with the grid 13 to form a third photoresistive element. The photoresistive elements, as illustrated, are connected to form an unbalanced T attenuator. An equivalent circuit is shown in Figure 9 wherein the resistors 16, 17 and 18 represent the photoresistive elements which form the T network. Each of the photoresistive elements is indicated as being variable, corresponding to the optical variation of resistance.
The grid network is covered with a layer of photoresistive material 15 (Figure 2) whereby adjacent grids are interconnected through the material. When the photoresistive material is dark, the resistance between grid elements is relatively high. With increasing illumination, the resistance is lowered an amount corresponding to the intensity and area of the illumination. The photoresistive material may be in the form of a powder which is dispersed in a binder and applied to the surface to form a relatively thin film. Alternatively, the powder may be dispersed in a carrier and applied to the grid network and the assembly is placed in an oven and baked at a relatively high temperature to form a sintered photoconductive layer.
Referring to Figure 3, the shaded area 19 represents a light beam which is impinging upon the photoconductive layer 15. The resistance of the layer interconnecting the grids 13 and 14 is lowered. The resistance 18 represents the resistance between these grids. Thus, with the light as shown, the resistance 18 is considerably lowered whereby maximum attenuation is obtained in the attenuator. As the light beam is moved to the left, the shunt resistance 18 is raised and the series resistances 16 and 17 are lowered. With the light illuminating the photoconductive material interconnecting the grids 11, 12 and 13, the shunt resistance is at its maximum and the series resistances 16 and 17 are at a minimum.. The attenuation introduced by the attenuator is at a minimum.
The geometry of the light pattern and the grid can be varied as desired to give the desired variation in resistance between the various elements to thereby control the input and output impedance as well as the attenuation introduced.
Referring to Figure 4, an alternative means for controlling the attenuation is shown. A light filter 21 is interposed between the light source 22 and the attenuating network 23. By moving the filter as indicated by the arrow 24, the illumination on various portions of the photoresistive material may be altered to control the resistance between the related grid elements. The filter 21 may be graded as shown in Figure 5 whereby a de-- sired variation of resistance with movement of the filter may be obtained.
In Figure 6 another means is shown for controlling the light incident upon the photoconductive material. An opaque shutter 2-6 having an optical cam 27 is moved as indicated by the arrow 28 between the light source and the material. In Figure 7 an opaque bafile 29 is interposed between a pair of lights 31 and 32 which may be independently controlled. By controlling the intensity of the lights 31 and 32, the attenuation and impedance of the attenuator network may be controlled. The attenuation may be controlled by moving the attenuator network. Thus, in Figure 8 the network is pivoted about the point 33.
The illumination may be electronically controlled by controlling the motion of the filter or shutter. Alternatively, one or more lights may be arranged whereby the attenuation can be controlled by controlling the power supplied to the light, as illustrated in Figure 7.
It is, of course, apparent that although a three terminal attenuator network has been described that other attenuator networks with more or less terminals may be constructed in accordance with the teaching of the invention.
It is seen that an attenuator is provided in which the resistance elements are optically controlled. The attenuation may be electronically controlled by electronically controlling the motion of the filter or shutter, or by controlling the intensity of the lights. The resistance may be mechanically controlled by moving the various elements as desired. The resistance arms of the attenuator network may be varied in accordance with any desired function by suitably, contouring the light cam, grading the filter or choosing the shape of the light beam.
I claim: I
1. A network comprising an interlaced grid network of conductive material, photoconductive material serv-g ing to interconnect the grids'of said network, said gridl network comprising four separate grids so disposed as to. form together with said photoconductive.material the resistive elements of a T-network, a light source, and means for controlling the light incident upon said photo-l conductive material whereby the attenuation and impedance level may be controlled as desired.
2. An attenuator network as in claim 1 wherein saidlight source emits a beam of predetermined pattern, and means are included for moving said beam relative to the interlaced grid network; V
3. An attenuator network as in claim 1 wherein said References Cited in the file of this patent UNITED STATES PATENTS 1,937,796 Smith et al. Dec. 5, 1933 2,643,297 Goldstein et al. June 23, 1953 2,674,154 Crandell Apr. 6, 1954 2,700,318 Snyder Jan. 25, 1955 2,768,310 Kazan et a1 Oct. 23, 1956 2,836,766 Halstead May 27, ,1958 2,856,589 Kazan Oct, 14,, 1958
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US669149A US2896086A (en) | 1957-07-01 | 1957-07-01 | Attenuator network |
Applications Claiming Priority (1)
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US669149A US2896086A (en) | 1957-07-01 | 1957-07-01 | Attenuator network |
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Cited By (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3072795A (en) * | 1961-05-12 | 1963-01-08 | Altec Lansing Corp | Remote volume control |
US3087069A (en) * | 1959-08-12 | 1963-04-23 | Giannini Controls Corp | Radiation-controlled variable resistance |
US3093741A (en) * | 1960-09-02 | 1963-06-11 | Meyer John Stirling | Photovoltaic device for translating signals |
US3121795A (en) * | 1961-05-05 | 1964-02-18 | Ncr Co | Photovoltaic apparatus for measuring displacement of an element |
US3128386A (en) * | 1959-09-22 | 1964-04-07 | Harold K Hughes | Radiation sensitive low-torque transducer |
US3134907A (en) * | 1960-02-08 | 1964-05-26 | Gen Dynamics Corp | Character generator |
US3146352A (en) * | 1962-05-18 | 1964-08-25 | Ncr Co | Electro-optical multivibrator using electroluminescent and photoconductive elements |
US3159750A (en) * | 1962-10-01 | 1964-12-01 | Eugene I Kazan | Photoelectric pressure transducer |
US3171034A (en) * | 1961-12-21 | 1965-02-23 | Tomasulo Walter | Electro-optical control |
US3192393A (en) * | 1962-01-17 | 1965-06-29 | Gen Precision Inc | Optical phase sensitive incremental encoder |
US3193686A (en) * | 1963-05-07 | 1965-07-06 | Western Electric Co | Photosensitive detectors and methods utilizing photosensitive detectors for positioning articles |
US3194967A (en) * | 1960-02-26 | 1965-07-13 | Ass Elect Ind | Variable electrical impedances |
US3196278A (en) * | 1961-09-12 | 1965-07-20 | Cutler Hammer Inc | Area type photo-electric control device |
US3202827A (en) * | 1961-06-29 | 1965-08-24 | Cummins Chicago Corp | Photocell for detecting limited moving shadow areas |
US3222601A (en) * | 1962-07-10 | 1965-12-07 | Martin Marietta Corp | Antenna beam scanner |
US3223846A (en) * | 1962-01-02 | 1965-12-14 | Giannini Controls Corp | Photosensitive optical fluid stream direction indicator |
US3225206A (en) * | 1962-03-14 | 1965-12-21 | Borg Warner | Photosensitive inspection apparatus for filamentary material |
US3258601A (en) * | 1966-06-28 | Photosensitive variable resistance device | ||
DE1238224B (en) * | 1962-03-14 | 1967-04-06 | Borg Warner | Device for testing the thickness of thread-like material |
US3639769A (en) * | 1969-04-10 | 1972-02-01 | William D Clark | Photoconductive potentiometer using variable transmittance control strips |
US3761718A (en) * | 1972-09-07 | 1973-09-25 | Honeywell Inc | Detector apparatus using semiconductor laminae |
US3806895A (en) * | 1971-09-16 | 1974-04-23 | Nippon Musical Instruments Mfg | Photoconductive memory device |
US3868658A (en) * | 1971-09-27 | 1975-02-25 | Siemens Ag | Device for optical superheterodyne information reading |
US4114035A (en) * | 1976-01-30 | 1978-09-12 | Rca Corporation | Position encoder employing charge transfer circuit |
US4260256A (en) * | 1978-11-17 | 1981-04-07 | Eastman Kodak Company | Apparatus for measuring illuminance |
US5315104A (en) * | 1990-05-01 | 1994-05-24 | Bt&D Technologies | Photodiode photodetector with adjustable active area |
US5376785A (en) * | 1992-10-02 | 1994-12-27 | Chin; Philip K. | Optical displacement sensor utilizing optical diffusion |
US5703357A (en) * | 1993-09-27 | 1997-12-30 | Shih; Ishiang | Methods for wavelength discrimination of monochromatic light beams |
US5999271A (en) * | 1998-06-01 | 1999-12-07 | Shih; Ishiang | Methods and devices to determine the wavelength of a laser beam |
US6573488B1 (en) * | 1998-10-13 | 2003-06-03 | Hamamatsu Photonics K.K. | Semiconductor position sensitive detector |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1937796A (en) * | 1931-01-23 | 1933-12-05 | Int Communications Lab Inc | Attenuating and selecting circuts |
US2643297A (en) * | 1948-12-03 | 1953-06-23 | Fed Telecomm Lab Inc | Gas discharge transmission arrangement |
US2674154A (en) * | 1949-05-21 | 1954-04-06 | Photo Res Corp | Photometric device |
US2700318A (en) * | 1951-10-03 | 1955-01-25 | Snyder James | Gun muzzle blast azimuth indicator |
US2768310A (en) * | 1954-12-28 | 1956-10-23 | Rca Corp | Distributed gap electroluminescent device |
US2836766A (en) * | 1956-05-15 | 1958-05-27 | Gen Electric | Electroluminescent devices and circuits |
US2856589A (en) * | 1954-04-20 | 1958-10-14 | Rca Corp | Light-controlled waveguide attenuator |
-
1957
- 1957-07-01 US US669149A patent/US2896086A/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1937796A (en) * | 1931-01-23 | 1933-12-05 | Int Communications Lab Inc | Attenuating and selecting circuts |
US2643297A (en) * | 1948-12-03 | 1953-06-23 | Fed Telecomm Lab Inc | Gas discharge transmission arrangement |
US2674154A (en) * | 1949-05-21 | 1954-04-06 | Photo Res Corp | Photometric device |
US2700318A (en) * | 1951-10-03 | 1955-01-25 | Snyder James | Gun muzzle blast azimuth indicator |
US2856589A (en) * | 1954-04-20 | 1958-10-14 | Rca Corp | Light-controlled waveguide attenuator |
US2768310A (en) * | 1954-12-28 | 1956-10-23 | Rca Corp | Distributed gap electroluminescent device |
US2836766A (en) * | 1956-05-15 | 1958-05-27 | Gen Electric | Electroluminescent devices and circuits |
Cited By (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3258601A (en) * | 1966-06-28 | Photosensitive variable resistance device | ||
US3087069A (en) * | 1959-08-12 | 1963-04-23 | Giannini Controls Corp | Radiation-controlled variable resistance |
US3128386A (en) * | 1959-09-22 | 1964-04-07 | Harold K Hughes | Radiation sensitive low-torque transducer |
US3134907A (en) * | 1960-02-08 | 1964-05-26 | Gen Dynamics Corp | Character generator |
US3194967A (en) * | 1960-02-26 | 1965-07-13 | Ass Elect Ind | Variable electrical impedances |
US3093741A (en) * | 1960-09-02 | 1963-06-11 | Meyer John Stirling | Photovoltaic device for translating signals |
US3121795A (en) * | 1961-05-05 | 1964-02-18 | Ncr Co | Photovoltaic apparatus for measuring displacement of an element |
US3072795A (en) * | 1961-05-12 | 1963-01-08 | Altec Lansing Corp | Remote volume control |
US3202827A (en) * | 1961-06-29 | 1965-08-24 | Cummins Chicago Corp | Photocell for detecting limited moving shadow areas |
US3196278A (en) * | 1961-09-12 | 1965-07-20 | Cutler Hammer Inc | Area type photo-electric control device |
US3171034A (en) * | 1961-12-21 | 1965-02-23 | Tomasulo Walter | Electro-optical control |
US3223846A (en) * | 1962-01-02 | 1965-12-14 | Giannini Controls Corp | Photosensitive optical fluid stream direction indicator |
US3192393A (en) * | 1962-01-17 | 1965-06-29 | Gen Precision Inc | Optical phase sensitive incremental encoder |
DE1238224B (en) * | 1962-03-14 | 1967-04-06 | Borg Warner | Device for testing the thickness of thread-like material |
US3225206A (en) * | 1962-03-14 | 1965-12-21 | Borg Warner | Photosensitive inspection apparatus for filamentary material |
US3146352A (en) * | 1962-05-18 | 1964-08-25 | Ncr Co | Electro-optical multivibrator using electroluminescent and photoconductive elements |
US3222601A (en) * | 1962-07-10 | 1965-12-07 | Martin Marietta Corp | Antenna beam scanner |
US3159750A (en) * | 1962-10-01 | 1964-12-01 | Eugene I Kazan | Photoelectric pressure transducer |
US3193686A (en) * | 1963-05-07 | 1965-07-06 | Western Electric Co | Photosensitive detectors and methods utilizing photosensitive detectors for positioning articles |
US3639769A (en) * | 1969-04-10 | 1972-02-01 | William D Clark | Photoconductive potentiometer using variable transmittance control strips |
US3806895A (en) * | 1971-09-16 | 1974-04-23 | Nippon Musical Instruments Mfg | Photoconductive memory device |
US3868658A (en) * | 1971-09-27 | 1975-02-25 | Siemens Ag | Device for optical superheterodyne information reading |
US3761718A (en) * | 1972-09-07 | 1973-09-25 | Honeywell Inc | Detector apparatus using semiconductor laminae |
US4114035A (en) * | 1976-01-30 | 1978-09-12 | Rca Corporation | Position encoder employing charge transfer circuit |
US4260256A (en) * | 1978-11-17 | 1981-04-07 | Eastman Kodak Company | Apparatus for measuring illuminance |
US5315104A (en) * | 1990-05-01 | 1994-05-24 | Bt&D Technologies | Photodiode photodetector with adjustable active area |
US5376785A (en) * | 1992-10-02 | 1994-12-27 | Chin; Philip K. | Optical displacement sensor utilizing optical diffusion |
US5703357A (en) * | 1993-09-27 | 1997-12-30 | Shih; Ishiang | Methods for wavelength discrimination of monochromatic light beams |
US5999271A (en) * | 1998-06-01 | 1999-12-07 | Shih; Ishiang | Methods and devices to determine the wavelength of a laser beam |
US6573488B1 (en) * | 1998-10-13 | 2003-06-03 | Hamamatsu Photonics K.K. | Semiconductor position sensitive detector |
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