US3887842A

US3887842A - Electronmagnetic deflection display system including dual mode deflection amplifiers and output power limited power supplies

Info

Publication number: US3887842A
Application number: US374730A
Authority: US
Inventors: Jr Abner Owens; Donald Weinstein
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1973-06-28
Filing date: 1973-06-28
Publication date: 1975-06-03
Anticipated expiration: 1992-06-03

Abstract

An electromagnetic deflection display system for both random stroke and raster displays provides larger, faster and brighter displays with reduced power consumption and physical size. Dual mode deflection amplifiers having independent linear and slew characteristics provide reduced slewing time without any significant increase in power consumption and system power is limited to a predetermined average value to reduce system size and weight.

Description

United States Patent Owens, Jr. et a1.

Inventors: Abner Owens, .Ir., Pompton; Donald Weinstein, Fair Lawn, both of NJ.

The Bendix Corporation, Teterboro, NJ.

Filed: June 28, 1973 Appl. No.: 374,730

Assignee:

U.S. Cl 3lS/397; 315/399 Int. Cl I-IOIj 29/70; HOlj 29/76 Field of Search 315/27 TD, 27 R, 397, 399

June 3, 1975 3,801,858 4/1974 Grangaard et al 315/27 TD OTHER PUBLICATIONS Handbook of Operational Amplifier Applications 151 Ed, Arizona, Burr-Brown Research Corp., 1963, P. 53.

Primary Examiner-Maynard R. Wilbur Assistant Examiner-T. M. Blum Attorney, Agent, or Firm-Anthony F. Cuoco; S. H. I-lartz [57] ABSTRACT An electromagnetic deflection display system for both random stroke and raster displays provides larger, faster and brighter displays with reduced power consumption and physical size. Dual mode deflection amplifiers having independent linear and slew character istics provide reduced slewing time without any significant increase in power consumption and system power [56] Reierences Cited UNITED STATES PATENTS is limited to a predetermined average value to reduce 3.499979 3/1970 Fiorletta 315 27 TD System and 3,786,303 1/1974 Hilburn 315/27 TD 8 Claims, 8 Drawing Figures l 40 42 t /\/'Z/\, F/ l f 3 48 h-NVM B 52 l I 44 f 38 L/ 50 l r 36 i 4 PREAMP 1 26- l SWITCHING SHEET INCREASING DUTY CYCLE PERCENT PEAK OUTPUT POWER FIG. 7

WE JTFM JIIEI I975 IU-I 887 842 SHEET 4 MAX. FREQ. AND AMPLITUDE SATURATION SATURATION SLEW SLEW\ E M OUTPUT DUAL MODE AMPLIFIER NON -DUAL MODE AMPLIFIER WAVESHAPES WAVESHAPES FIG. 4A FIG. 4B

HTENTEUJUH ms 3,887,842

SHEET 6 E (FIG.2)

FIG. 5

A FOR +v l I if A FOR -v SUPPLY OUTPUT CURRENT OUTPUT CURRENT VS TIME-EXCEEDED RECYCLING TRIGGER PONT M 8' FOR +v A /PEAK POWER A' FOR v H H H H H A FOR -v 7 SUPPLY I I l OUTPUT CURRENT U 5 FOR +v A A A A A 8' FOR -v \I \n c FOR+VL COMPARATOR HYSTERES IS FIG. 6

ELECTRONMAGNETIC DEFLECTION DISPLAY SYSTEM INCLUDING DUAL MODE DEFLECTION AMPLIFIERS AND OUTPUT POWER LIMITED POWER SUPPLIES BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates generally to display systems and particularly to display systems with electromagnet ically deflected cathode ray tube random stroke and TV raster displays such as described and claimed in commonly assigned copending U.S. application Ser. No. 374,736, filed on June 28, l973'by Abner Owens, Jr. More particularly, this invention relates to systems of the type described including dual mode deflection amplifiers for reducing slewing time without significantly increasing power consumption and power supplies which are output power limited for reducing quiescent system power consumption as well as the size I and weight of the system such as described and claimed in commonly assigned copending U.S. application Ser. No. 374,735, filed on June 28, 1973 by Abner Owens, .Ir.

2. Description of the Prior Art Of major concern in electromagnetically deflected cathode ray tube (CRT) display systems is the significant increase in power consumption with larger, faster and brighter displays. These items become even more critical with the highly sophisticated airborne navigation displays required in modern, high speed aircraft, where size, weight and powper are at a premium.

The choice of deflection type for a given display system is a function of three major factors; (a) the CRT light output requirement, and hence the final CRT anode voltage, (b) the deflection angle, which is a function of the maximum available CRT length and packaging geometry, and (c) the maximum allowable power dissipation. The primary requirement for the deflection amplifiers for an electromagnetically deflected CRT is that of supplying accurately controlled currents to the deflection yokes. For apparatus which serves this purpose reference may be had to U.S. Pat. No. 3,426,245 issued Feb. 4, I969 to John F. Yurasek and Abner Ownes, Jr. for a High Speed Magnetic Deflection Amplifier, and assigned to The Bendix Corporation, assignee of the present invention.

An additional area of concern is the slew rate of the deflection amplifiers. Amplifier slew rate design criteria (which also affect peak power requirements) are dictated primarily by display content and format requirements and may be relaxed by minimizing the amount of information to be presented by the display at any one time. In this connection reference may be had to U.S. Pat. application Ser. No. 1 12,358 filed Feb. 9, 1971 by Abner Ownes, Jr. and Donald Weinstein for Means for Conserving Energy During Line Retrace of a Raster Type Display, and which application is assigned to The Bendix Corporation, assignee of the present invention.

The present invention describes a system including slewing means whereby power may be significantly reduced for any type of display i.e., periodic or aperiodic. The system includes fast slewing switching dual mode deflection amplifiers and output power limited power supplies to achieve the desired results with reduced power consumption and reduced weight and size.

SUMMARY OF THE INVENTION This invention contemplates an electromagnetic deflection display system wherein input signals from, for example, a symbol generator are applied to deflection amplifiers, and which amplifiers drive X and Y deflection yokes of a CRT. The deflection amplifiers are of the dual mode type having independent linear and slew modes of operation and with three distinct stages, i.e. a preamplifier stage, a fast slew switching stage and an output stage. The amplifiers are powered by power supplies which operate at predetermined duty cycles whereby the power to the system is at a predetermined average value. The system features larger, faster and brighter display presentations while achieving significant reduction in system power consumption and physical size.

The main object of this invention is to provide an electromagnetic deflection display system providing larger, faster and brighter displays with significant reductions in total system power consumption and physical size.

Another object of this invention is to provide an electromagnetic deflection display system of the type described for both random stroke writing and TV raster displays, and having dual mode deflection amplifiers and output power limited power supplies, with system power consumption and weight and size significantly reduced.

Another object of this invention is to provide a system of the type described including dual mode deflec tion switching amplifiers having independent linear and slew characteristics whereby the slewing time is reduced without a significant increase in power consumption.

Another object of this invention is to provide a system of the type described including power supplies where the power to the system is limited to a predetermined average value to reduce the quiescent power consumption of the system and significantly reduce systern, size and weight.

The foregoing and other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein several embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration purposes only and are not to be construed as defining the limits of the invention.

DESCRIPTION OF THE DRAWINGS FIG. I is a block diagram of an electromagnetic deflection display system according to the invention.

FIG. 2 is an electrical schematic diagram of the dual mode switching deflection amplifiers shown generally in FIG. 1.

FIG. 3 is an electrical schematic diagram showing a linear model of the amplifiers shown schematically in FIG. 2.

FIGS. 4A-4B are graphical representations showing waveforms at various points of dual mode (FIG. 2) and non-dual mode deflection amplifiers, respectfully.

FIG. 5 is an electrical schematic diagram of the output power limited linear and slew power supplies shown generally in FIG. 1.

3 fit... 6 is a graphical representation showing waveforms at various points of the power supply shown schematically in FIG. 5.

FIG. 7 is a graphical representation showing output power characteristics versus time of the power supply shown schematically in FIG. 5.

DESCRIPTION OF THE INVENTION With reference to FIG. 1, a symbol generator 2 provides X and Y and cathode ray tube (CRT) deflection signals and a Z bright-up signal. Symbol generator 2 is of the type described in copending U.S. application Ser. No. 152,927 filed on June I4, 1971 by Kenneth J. Kendall et al, and assigned to The Bendix Corporation. assignee of the present invention. It will suffice to say for purposes of the present invention that the X. Y and Z signals from symbol generator 2 are applied to the appropriate circuits of a CRT 4 for providing symbology on the face of the CRT in response to signals from an external source, and which symbology may be used for flight control purposes.

Signal X from symbol generator 2 is applied to a switching deflection amplifier 6 and signal Y from the symbol generator is applied to a similar switching deflection amplifier 8.

Switching deflection amplifiers

6 and 8 are of the type which will be hereinafter described with reference to FIG. 2. The switching amplifiers are powered by a linear power supply 10 providing voltages +V and V, and a similar slew power supply 12 providing voltages +V Power supplies 10 and 12 are of the type which will be hereinafter described with reference to FIG. 5.

The Z signal from symbol generator 2 is applied to a conventional type video bright-up amplifier 14. Amplifier 14 is powered by a conventional power supply 16.

Switching deflection amplifier 6 is connected to an X-axis deflection yoke 18 of CRT 4 and switching deflection amplifier 8 is connected to a Y-axis deflection yoke of the CRT. Video bright-up amplifier 14 is connected to an appropriate bright-up electrode 19 of CRT 4. CRT 4 is powered by a conventional high voltage power supply 13.

It will now be understood that the electromagnetic deflection system shown in FIG. 1 is effective for both random stroke writing and TV raster displays.

Amplifiers

6 and 8 are dual mode deflection amplifiers having independent linear and slew characteristics, whereby the slewing time may be significantly reduced as com pared to a non-dual arrangement. with no significant increase in power consumption as will be hereinafter explained. Power supplies 10 and 12 are of the type whereby the output power of the system is limited to a prescribed average value thus reducing system quiescent power consumption of the deflection system to significantly reduce the size and weight of the system as will also be hereinafter explained.

It will be understood that CRT display edge to edge slew time varies anywhere from 100 microseconds to l microsecond depending on (a) whether the display is random stroke writing/symbology or of the TV raster type and (b) the display content and format. The above. of course. implies nonstorage type displays with frame rates in the order of 50 Hz. to 60 Hz. In random stroke type displays, as display content increases so must the slew rate. In the TV raster type display. slewing is the flyback time. which increases with an increase in the number of TV lines per frame. In the dual mode deflection system of the present invention the slewing mode requirement is virtually independent of the linear mode requirement as will become evident.

Thus. with reference to FIG. 2 wherein an amplifier such as the

amplifier

6 and 8 will be described. the amplifier includes a preamp stage 22, a switching stage 26 and an output or emitter follower stage 28.

Preamp stage 22 includes a very wide band high gain operational amplifier 30 having an input terminal 32 at which an input signal A is received through a resistor 34 and a grounded input/output terminal 36. Amplifier 30 has an output terminal 38 at which a signal B is provided. A feedback loop including a resistor 40 and a serially connected variable capacitor 42 is connected to input terminal 32 and to output terminal 38 of amplifier 30.

Output terminal 38 of amplifier 30 is preamp stage 22 is connected to an input terminal 44 of a switching amplifier 46 in switching stage 26. Amplifier 46 includes a power terminal 48 connected to a slew power supply. such as the power supply 12, (FIG. 1) for receiving voltage -t-V t. and a power terminal 50 connected to power supply 10 for receiving voltage V Amplifier 46 includes an output terminal 52 at which a signal C is provided. Switching stage 26 includes

transistors

54 and 60.

Output stage 28 includes

transistors

56 and 58. The base element of

transistors

54 and 60 are connected intermediate output terminal 38 of amplifier 30 and input terminal 44 of amplifier 46. The base elements of

transistors

56 and 58 are connected to output terminal 52 of amplifier 46. The emitter element of transistor 54 is connected to power terminal 48 of amplifier 46 and the emitter element of transistor 60 is connected to power terminal 50 of amplifier 46. The collector elements of

transistors

54 and 56 are connected one to the other and the collector elements of

transistors

58 and 50 are connected one to the other. The emitter elements of

transistors

56 and 58 are connected one to the other and a signal D is provided at a point 62 intermediate said emitter elements.

Voltage +V from power supply 10 is applied through a steering diode 64 to the collector elements of

transistor

54 and 56 and voltage V from the power supply is applied through a steering diode 6 to a point 65 intermediate the collector elements of

transistors

58 and 60. A deflection yoke such as the deflection yoke 18, 20 (FIG. I) and shown for purposes of illustration as yoke 18 includes a coil 70, a resistor 71 and a current sampling resistor 72 connected in series. Coil is connected to point 62. A feedback resistor 74 is connected intermediate resistor 34 and input 32 of amplifier 30 and is connected to a point 76

intermediate resistors

71 and 72, and at which point 76 a signal E is provided. Waveforms for signals. A. B. C. D. and E are shown in the graphical illustration of figures 4A-4B, and which figures will be hereinafter referred to.

The band width of amplifier 30 is a function of overall display system requirements which may vary from 60 Hz. to It) MHz. The feedback loop including resistor 40 and capacitor 42 around amplifier 30 controls the response shape with respect to yoke shape while maintaining high DC feedback for position stability. This is accomplished by adjusting the RC time constant of the feedback loop to cause a zero to occur at the pole caused by the yoke time constant. Therefore. during the linear mode of operation the deflection amplifier is extremely stable since yoke 18, which is a linearpassive element, and not the amplifier, will cause a natural roll off of (DB per octave in the system. In the linear mode the maximum linear band width of amplifier 30 is essentially, a function of yoke inductance, the positive and negative power potentials and the input voltage amplitude.

With reference to FIG. 3 which is a linear model of the deflection amplifier shown in schematic form in FIG. 2, a relationship involving the pertinent parameters may be determined as follows:

Equation 1) may be normalized for more general use as follows:

where:

R /R,=closed loop again w0=input frequency w, =yoke time constant (-3DB point) From equation (2) it can be seen that with m m D/A is essentially equal to R1'4/R34 and the amplifier closed loop gain is in the order of from ()l to 0.5 for this type of amplifier.

It will now be understood that as input frequency (0) increases beyond (01 and holding A constant, D rises to the power of two. This is, of course, due to the induction reactance of yoke 18.

From FIG. 2 it can be seen that D is equivalent to the supply potentials :V Therefore, the maximum linear large signal bandwidth of the deflection amplifier is readily predictable, i.e. knowing the closed loop gain R2q/ 24, yoke time constant to, and setting A to maximum (usually i5 volts) with D= '"V, w may be determined. For maximum linear small signal bandwidth one would simply adjust A to the smallest excusion applicable to the specific system.

As the input frequency and amplitude go beyond the maximum linear large signal bandwidth limits, the deflection amplifier as shown in FIG. 2 is said to go into the slew or non-linear mode. While slewing, the output current waveform of the amplifier no longer represents the input voltage waveform, and the amplifier effec' tively becomes open loop and saturates.

FIG. 4A illustrates voltage waveforms within the dual mode deflection amplifier of the invention (FIG. 2) while FIG. 4B shows the waveforms of the same amplifier with the switching stage 26 removed. Thus, with the switching stage removed the slewing time is not independent of the linear mode of operation but is dependent on the potential iV as shown in FIG. 4B. If the linear signal bandwidth requirement is low, iv, will be relatively low and the slew time will be long which may not be desirable. Increasing :tV to decrease the slewing time will increase the large signal unnecessarily and, more significantly, increase the system power consumption.

A typical situation in which the aforementioned is obvious is in the horizontal sweep voltage of a TV raster display where the linear sweep time is about 85 percent longer than the slewing or flyback time. In the dual mode deflection amplifier of the present invention, the potential iv, is chosen for the maximum large signal bandwidth while the switched input potential :v which may be much higher than iV is selected for the slewing time requirements see (FIGS. 2 and 4A). Voltage tV is determined by the following equation.

L=yoke inductance 3;

I=yoke current maximum deflection, center to edge T=slew time required Referring to FIGS. 2 and 4A, the dual mode deflection amplifier such as the

amplifiers

6 and 8 of the invention operates as will be next described.

When input signal A exceeds the linear bandwidth and amplitude, the dual mode deflection amplifier effectively becomes open loop as heretofore explained. Preamp stage 22 then saturates going far beyond the design linear region to provide waveform B in FIG. 4A. This action also causes stage 26 to saturate to the high switching voltage iv, to provide waveform C. At the same time the output of the switching stage applies voltage iV to the bases of the

output stage transistors

56 and 58 and the preamp saturation causes

transistors

54 and 60 to saturate applyinig iV to the collectors of

transistors

56 and 58 respectively. As the collectors of

transistors

56 and 58 rise to

1V diodes

64 and 66 become reverse biased and disconnect the linear power supply iV The rise and fall time of waveform E shown in FIG. 43 decreases significantly to that shown in FIG. 4A. Using this technique, slew time may be reduced by a minimum of five times that of the non-dual approach without any increase in system power as will now be understood.

The electromagnetic deflection display system and the dual mode switching amplifier apparatus heretofore discussed offers a significant reduction in system power requirements. The power supply of the invention which will be next described operates at predetermined duty cycles and provides still further reductions in system power and physical size of the equipment involved.

The equipment involved will be described, for purposes of illustration, with reference to TV raster and random stroke writing type display systems such as used in aircraft head-up or head-down displays or simulators. It will be understood that these systems imply a non-storage type display with refresh rates in order of 60 Hz. Further, in analyzing these systems certain pre dictions can usually be made with respect to the display formats. With TV raster display there is, of course, the raster format which is accurately predictable at any instant i.e., the linear sweep in either the vertical or horizontal and the slew during the respective flybacks. The random stroke format is more difficult to predict except for the refresh rate. However, more often than not some generalities can be attributed to most random stroke displays other than the refresh rate. For exam ple, in a random stroke system the CRT electron beam will not stay positioned in one corner of the display for more than one millisecond. As a matter of fact, in most systems the CRT phosphor protection device will sense no motion within this one millisecond period which could present a display problem, and the CRT beam is turned off. Essentially, then, the length of time that the CRT electron is along the outer perimeter of the dis play surface will determine peak power duration for the random stroke system. The same analysis may be made for the TV raster mode of operation. Thus, it appears that since peak power is required only for short periods of maximum deflection, and the power requirements decrease to much lower than peak for a larger portion of the frame time, it is desirable to develop a power supply system to fulfill these requirements.

With this in mind, the power supply systems of the present invention have been designed with maximum output power equal to the average power requirements of the system. Thus, there is provided a significant reduction in quiescent power, heat generated, and system size and weight.

FIG. shows in substantial detail a power supply according to the invention such as the power supplies shown generally in FIG. 1 and designated by the

numbers

10 and 12, and wherein power supply 12 providing signal +V will be described for purposes of illustration, with another such power supply being required for providing signal -V An unregulated dc voltage source 80 shown in FIG. 5 provides a positive voltage which is applied to an input terminal 82 of a current amplifier 84, and provides a negative voltage which is applied to an input terminal 88 of a correction amplifier 90. Correction amplifier 90 has

other input terminals

92 and 94 and an output terminal 96 connected to a control terminal 98 of current amplifier 84. Current amplifier 84 has an output terminal 100 connected to a power source terminal 102 through a current sampling resistor 104.

Output terminal 100 of current amplifier 84 is connected to an input terminal 106 of an integrating amplifier 108. An input terminal 110 of amplifier 108 is connected to power output terminal 102. Amplifier 108 has an output terminal 112 connected to an input terminal 114 of a comparator amplifier 116. Comparator amplifier 116 has an output terminal 118 connected to input terminal 94 of correction amplifier 90.

Output terminal 100 of current amplifier 84 is connected to an input terminal 120 of a zero sensor 122 and another input terminal 124 of zero sensor 122 is connected to power output terminal 102. Zero sensor 120 has an output terminal 126 connected to a control terminal 117 of integrator 108.

A power supply return terminal 128 is connected to DC voltage source 86 and serially connected

resistors

130 and 132 are connected across

terminals

102 and 128. Input terminal 92 of correction amplifier 90 is connected at a point 134

intermediate resistors

130 and 132. Integrator 108, zero sensor 122 and comparator amplifier 116 are included in a power limit sensor generally by the number 136.

In operation, the voltage developed across current sampling resistor 104 is a function of the current flowing through the resistor. This voltage waveform is integrated by integrator 108 in power limit sensor 136,

whose maximum rate is a function of how long the CRT From the configuration shown in FIG. 5, it will be understood that power limit sensor 136 may be used as short circuit protection circuitry and the system will keep recycling on a short circuit.

Resistors

130 and 132 and correction amplifier provide a positive feedback network as is shown in the figure.

For a deflection system such as shown in FIG. I, there are four power supplies (two power supplies 10 and two power supplies 12) such as the power supply shown in FIG. 5, two for the linear mode and two for the slew mode. It will be understood that any number of power supplies, may be used as well, depending on the specific format of the display. The linear power supplies will always be of the type described with reference to FIG. 5. However, if there are not system slew requirements the slew power supplies are not necessary. Also, in some systems the only slew requirement is during the retrace or flyback of the horizontal sweep of the TV raster, and thus the slew mode is only required in the negative direction and a power supply providing voltage V is the only one necessary.

FIG. 6 illustrates waveforms for signals at various points of the power supply described with reference to FIG. 5, and which signals are designated in FIGs. 5 and 6 as A, B and C'. It should be noted from waveform A of FIG. 6, that relative average power is low and durations of peak power are relatively small. Some typical values of peak output ratios are; for iV about 30 per cent of peak and for iV about l6 percent of peak.

FIG. 7 is a graphical illustration showing the output power characteristics versus time of the power supply concept of the invention. The curve of FIG. 7 basically follows the square law; the plateau at percent power output is a function of the duty cycle of the system and as the duty cycle increases the curve moves in the direction of the arrow.

It will now be seen that the aforesaid objects of the invention have been satisfied. An electromagnetic deflection display system for both random stroke writing and TV raster displays including dual mode deflection amplifiers (linear and slew) and output power limited power supplies contribute to decreased power consumption and system weight and size. The dual mode deflection amplifiers have independent linear and slew characteristics to provide reduced slewing time with no significant increase in power consumption. The output power limited power supply system, in limiting system power to a predetermined average value, reduces the quiescent power consumption of the system and further reduces system size and weight.

Although but several embodiments of the invention have been illustrated and described in detail, it is to be expressely understood that the invention is not limited thereto. Various changes may also be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

1. For use with an electromagnetic deflection display system of the type including means for providing deflection signals, deflection display means and power supply means providing linear mode output power and slew mode output power for powering the deflection display means, deflection amplifier means comprising:

preamp means for receiving the deflection signals;

output means for applying output power to the deflection display means; and

1, wherein the switching means includes:

switching means connected to the preamp means, to nected to the power supply and the emitter element the power supply means and to the output means connected to the first power terminal; and initially operative in a linear mode for applying the second control device includes a transistor having the linear mode output power to the output means a base element connected to the amplifier means and responsive to a at O Cha g Of the fifle input terminal, emitter and collector elements consignals above a predetermined rate for switching to nected to the power supply and the emitter element a slew mode of Operation to pp y the Slew connected to the second power terminal; P" Power to the Output mean; and the third control device includes a base element conthe linear and Slew mode of Operation being p nected to the amplifier output terminal, a collector f each other for redufllhg Slew time without element connected to the collector element of the mcmaslhg Power C(msumphohfirst control transistor and an emitter element con- 2. Deflection amplifier means as described by claim nected to the deflection display means; and 1, wherein the preamp means includesi the fourth control device includes a base element a wide band high gain amplifier having an input connected to the amplifier means output terminal,

minal for receiving the deflection Signals and a collector element connected to the collector ele- 0MP! terminal connected to the switching means; ment of the second control transistor and an emitand ter element connected to the emitter element of ffiedback having a resistor and a i the third control transistor and to the deflection nected capacitor, and connected to the input and display means output 2O 6. Deflection amplifier means as described by claim 3. Deflection amplifier means as described by claim 5 wherein.

the power supply means provides slew mode power in one sense to the emitter element of the first transistor and slew mode power in the opposite sense to the emitter element of the second transistor; and the power supply means provides linear mode power in one sense to a point intermediate the collector elements of the first and third transistors and linear mode power in the opposite sense to a point intermediate the collector elements of the second and fourth transistors. 7. Deflection amplifier means as described by claim 6, including:

steering means connected to the power supply and to amplifier means having an input terminal connected to the preamp means, an output terminal connected to the output means and first and second power terminals;

first and second control devices connected to the amplifier means input terminal;

the first control devices connected to the power supply and to the first power terminal; and

the second control devices connected to the power supply and to the second input terminal.

4. Deflection amplifier means as described by claim 3, wherein the output means includes:

third and fourth control devices connected to the deflection display means and to the plifi means the point intermediate the collector elements of the output tel-mind; first and third control devices for applying the linthe third control device connected to the first control car mode Output Power in one Sense to Said P device and driven by the amplifier means for applyand ing output power to the deflection display means; 40 other Steering means connected t0 the P pp and to the point intermediate the collector eleand h f th control d i connected to h Second ments of the second and fourth control devices for control device and driven by the amplifier means pp yi g linear mode Output Po er in the Opposite for applying output power to the deflection display 561183 t0 aid point. means, 8. Deflection amplifier means as described by claim 5. Deflection amplifier means as described by claim 2, including: 4 h i feedback means including a resistor connected to the the first control device includes a transistor having a deflection display means and to the input terminal base element connected to the amplifier means of the wide band, high gain amplifier.

input terminal, emitter and collector elements con-

Claims

1. For use with an electromagnetic deflection display system of the type including means for providing deflection signals, deflection display means and power supply means providing linear mode output power and slew mode output power for powering the deflection display means, deflection amplifier means comprising: preamp means for receiving the deflection signals; output means for applying output power to the deflection display means; and switching means connected to the preamp means, to the power supply means and to the output means, and initially operative in a linear mode for applying the linear mode output power to the output means and responsive to a rate of change of the deflection signals above a predetermined rate for switching to a slew mode of operation to apply the slew mode output power to the output mean; and the linear and slew mode of operation being independent of each other for reducing slew time without increasing power consumption.

2. Deflection amplifier means as described by claim 1, wherein the preamp means includes: a wide band, high gain amplifier having an input terminal for receiving the deflection signals and an output terminal connected to the switching means; and feedback means having a resistor and a serially connected capacitor, and connected to the input and output terminals.

3. Deflection amplifier means as described by claim 1, wherein the switching means includes: amplifier means having an input terminal connected to the preamp means, an output terminal connected to the output means and first and second power terminals; first and second control devices connected to the amplifier means input terminal; the first control devices connected to the power supply and to the first power terminal; and the second control devices connected to the power supply and to the second input terminal.

4. Deflection amplifier means as described by claim 3, wherein the output means includes: third and fourth control devices connected to the deflection display means and to the amplifier means output terminal; the third control device connected to the first control device and driven by the amplifier means for applying output power to the deflection display means; and the fourth control device connected to the second control device and driven by the amplifier means for applying output power to the deflection display means.

5. Deflection amplifier means as described by claim 4, wherein: the first control device includes a transistor having a base element connected to the amplifier means input terminal, emitter and collector elements connected to the power supply and the emitter element connected to the first power terminal; the second control device includes a transistor having a base element connected to the amplifier means input terminal, emitter and collector elements connected to the power supply and the emitter element connected to the second power terminal; the third control device includes a base element connected to the amplifier output terminal, a collector element connected to the collector element of the first control transistor and an emitter element connected to the deflection display means; and the fourth control device includes a base element connected to the amplifier means output terminal, a collector element connected to the collector element of the second control transistor and an emitter element connected to the emitter element of the third control transistor and to the deflection display means.

6. Deflection amplifier means as described by claim 5, wherein: the power supply means provides slew mode power in one sense to the emitter element of the first transistor and slew mode power in the opposite sense to the emitter element of the second transistor; and the power supply means provides linear mode power in one sense to a point intermediate the collector elEments of the first and third transistors and linear mode power in the opposite sense to a point intermediate the collector elements of the second and fourth transistors.

7. Deflection amplifier means as described by claim 6, including: steering means connected to the power supply and to the point intermediate the collector elements of the first and third control devices for applying the linear mode output power in one sense to said point; and other steering means connected to the power supply and to the point intermediate the collector elements of the second and fourth control devices for applying linear mode output power in the opposite sense to said point.