US2854572A

US2854572A - Gate using variable cathode follower impedance for shorting or passing cathode-fed impulses

Info

Publication number: US2854572A
Application number: US429353A
Authority: US
Inventors: Robert M Strassner; Everett G Shover
Original assignee: Consolidated Electrodynamics Corp
Current assignee: Consolidated Electrodynamics Corp
Priority date: 1954-05-12
Filing date: 1954-05-12
Publication date: 1958-09-30
Anticipated expiration: 1975-09-30

Description

p 1958 R. M. STRASSNER ET AL GATE. USING VARIABLE CATHODE F OLLOWER IMPEDANCE FOR SHORTING OR PASSING CATHODE-FED IMPULSES Filed May 12, 1954 IOK IOK BIA SING MEANS NEGATIVE PULSE SOURCE fIQ FIG. 2. (b)

INVENTORS. ROBERT M. STRASSNER EVERETT 6. SHOVER KBW A T TORNE V United States Patent F GATE USING VARIABLE (IATHODE FOLLOWER IMPEDANCE FOR SHORTING R PASING CATHODE ED IMPUIQES Robert M. Strassner, (Zhicago, 111., and Everett G. Shover, Arcadia, Qalif, assignors, by mesne assignments, to Consolidated Electrodynamics Corporation, Pasadena, Calif., a corporation of California Application May 12, 1954, Serial No. 429,353

4 Claims. (Cl. 250-27) The present invention relates to signal transfer circuits and more particularly to circuits for selectively passing electrical impulses to an output circuit.

In electrical systems such as digital computing apparatus, a binary counter for counting a selected number of electrical pulses is frequently employed. Where four bistable circuits are employed as a binary counter the total number of permutations in the conditions of conduction of the bi-stable circuits equals 16. For some applications, however, it is desirable to limit the maximum count to a lesser number, say 10 counts. This may be accomplished by inhibiting the passage of counting impulses to selected ones of the bi-stable circuits so that one or more of the possible permutations is omitted.

In accordance with our invention we have provided an improved and simplified circuit for controlling the passage of electrical impulses to an output circuit, which may comprise a selected one of the bi-stable circuits in a binary counter.

In one embodiment, our invention includes an electron tube having a cathode, a primary anode, a control electrode, and two auxiliary electrodes adjacent to the cathode. By connecting a cathode resistor between the cathode and a reference potential, a back voltage is provided at the cathode by the passage of current between the cathode and the primary anode which tends to diminish current flow between the cathode and the auxiliary anodes. A source of negative pulses is coupled across the cathode resistor, an output circuit is connected to the auxiliary anodes, and a biasing means is coupled to the control electrode.

A better understanding of the operation and advantages of our invention may be had upon a reading of the following detailed description when taken in connection with the drawings, in which:

Fig. 1 is a combination block and schematic diagram of one embodiment of our invention; and

Fig. 2 is a graphical representation of certain of the electrical signals appearing in the embodiment of Fig. 1.

Referring in detail to Fig. 1, a signal transfer circuit is shown which includes an electron tube 3 having a primary anode, a control electrode, a cathode, and two auxiliary anodes 5 and 7. Several commercial electron tubes, which are readily available, include all of these electrodes. Ordinarily the auxiliary anodes are employed as second detectors and automatic volume control indicators in superheterodyne radios. The auxiliary anodes 5 and 7 share the cathode of the electron tube 3 with the primary anode.

A cathode impedance, such as a resistor 9, is connected between the cathode and a reference potential. The anode of the electron tube 3 may be energized by means of a terminal 11 which is adapted to be connected to a suitable source of positive potential (not shown). Biasing means 13, which is connected to the control electrode of the electron tube 3, provides a control potential for varying the flow of current between the cathode and the anode, and hence the voltage appearing across the cathode re- 2,854,572 Patented Sept. 30,1958

current flow between the cathode and the auxiliary anodes 5 and 7. On the other hand, if the voltage across the cathode resistor 9 is relatively small, the negative pulses from the negative pulse source 15 drive'the cathode negative with respect to the auxiliary anodes 5 and 7, thereby causing conduction and a negative pulse to pass to the output circuitry connected to the auxiliary anodes.

The relationship of the electrical signals involved is shown in Fig. 2 wherein Fig. 2(a) illustrates the signal provided by the inhibiting means 13in two conditions of operation. When the signal from the biasing means 13 is low, as indicated at 17, the negative pulses from the negative pulse source 15, as illustrated in Fig. 2(b), are passed to the output circuitry associated with the auxiliary anodes 5 and 7 as shown in Fig. 2(a).

On the other hand, when the signal provided by the biasing means 13 is high, as illustrated in Fig. 2(a) at 19,

the negative pulses provided by the negative pulse source 15, as illustrated in Fig. 2(b), do not appear at the auxiliary anodes 5 and 7 as illustrated in Fig. 2(c).

The particular output circuitry associated with the auxiliary anodes 5 and 7 of the illustrative embodiment of Fig. l is a conventional bi-stable circuit including two

cross-coupled electron tubes

21 and 23. The circuit is arranged so that a negative pulse applied to the control electrode of that electron tube of the bi-stable circuit which is conducting, will tend to decrease conduction therein, thereby resulting in an increase in potential at the anode, which in turn is coupled to the control electrode of the other of the cross-coupled electron tubes, so as to tend to increase conduction therein. This action is cumulative until the initially conducting electron tube becomes substantially cut oil, while the initially nonconducting electron tube becomes conducting. V

In a binary counter having a plurality of bi-stable circuits, the signal transfer circuit, including the electron tube 3, may be used to form what is sometimes termed a permuted binary counter. In a permuted binary counter, the maximum number of stable conditions of a. plurality of bi-stable circuits is decreased so that the counter may be adapted to count in a desired number system. For example, as noted above, four bi-stable circuits may be employed to count to 16, but Where the decimal system of notation is adhered to, and the decimal digits are coded in binary form, it is frequently desirable to count from 0 to 9 only. By including the signal transfer circuit of our invention in such a binary counter, any selected one of the bi-stable circuits may be inhibited from responding to counting pulses by applying a signal from another of the bi-stable circuits to the control electrode of the signal transfer electron tube 3. By this means, the condition of conduction of one of the bi-stable circuits determines Whether the selected bi-stable circuit will respond to incoming pulses.

Although the signal transfer circuit of our invention is shown in connection with a bi-stable circuit which may be used as a portion of a permuted binary counter, the signal transfer circuit is not limited thereto, since it may be employed to pass selectively, electrical pulses to an output circuit Wherever such is required. In addition, the electron tube types, the resistance values, and the power supply voltages given in Fig. 1 are exemplary only, being indicative of one embodiment of the invention which has operated satisfactorily. In Fig. 1 the values of the re- 3 sistancesare in ohms where K=1000 and the potential values are in volts.

We claim: 1. A signal transfer circuit for. selectively passing negative. pulses. to an output circuitiincluding in combination,.

an. electron tube. inchlding atleast a. cathode, a primary anode, a control electrode and one auxiliary anode located adjacent thev cathode, a cathode resistor connected between the cathode and a reference potential, means energizing, the primary anode of. the electron tube to provide. a current flow between the cathode and the primary anode, an output circuit. coupled to the. auxiliary anode, av source of negative pulses coupled across the cathode resistor, and. means coupled to the control electrode for biasing. the electron, tube: to providev a voltage across the cathode resistor of a polarity tending'to diminish conduction between the cathode and the auxiliary anode, whereby negative pulses from; the source of. negative pulses are inhibited from passing tothe output circuit.

2. A signal transfer circuit including in combination, an electron tube having atleast a. cathode, anode and control electrode, a diode sharing the cathode of the electron tube, an output circuit coupled serially with the diode, acathode impedance coupled between; the cathode and a reference potential, means: energizing the electron. tube to induce a current flow between. the cathode; and the anode, asource of negative pulses coupled across the cathode impedance, means biasing; the control electrode. of the electron tube to allow the. negative pulses to pass through the diode to the output circuit during one. condition of operation, and means,- biasing; the'control electrode of the electron, tube to inhibit, the. passage of negative pulses through the diode to the output circuit in another condition of operation. 7

3. In apparatus including a, binary counter having two stable conditions of operatiomthe combination of a pair of cross-coupled. electron tubes connected so that one of: the. electron tubes is conducting while the other electron tube is substantially cut off, a signal: transfer circuit ineluding. an electron tube having at. least a cathode, a

at primary anode, a control electrode and a pair of auxiliary anodes positioned adjacent the cathode, means coupling the auxiliary anodes to the cross-coupled electron tubes, a cathode resistor connected between the cathode and a reference potential, means energizing the primary anode positively with respect to the cathode, a source of negative pulses connected across the cathode resistor, means biasing the control electrode of the electron tube to permit negative pulses from the negative pulse source to be applied tothe cross-coupled electron tubes via the cathode and auxiliary anodes during one condition of operation, and said latter means biasing the control electrode of the electron tube to provide a voltage across the cathode resistor which tends to diminish current flow between the cathode and auxiliary anodes whereby negative pulses from the negative pulse source are inhibited from passing to the cross-coupled electron tubes via the cathode and auxiliary anodes in another condition of operationv 4, A signal transfer circuit including in combination, an electron tube having at least a cathode, anode, control electrode and auxiliary anode located adjacent the cathode, circuit means for supplying an operating potential to said anode, a cathode resistance connecting said cathode to a commonreference potential, a source of negative pulses. coupled across said cathode resistance, and a source of inhibiting signals coupled to said control electrode, said tube being responsive to said inhibiting signals to control the conduction between the cathode and auxiliary anode in response to said negative pulses.

References Cited in the file of this patent UNITED STATES PATENTS 2,466,959 Moore Apr. 12, 1949 2,478,683 Bliss Aug. 9, 1949 2,483,823 George Oct. 4, 1949 2,535,377 Titterton Dec. 26, 1950 2,566,933 Dickinson Sept. 4, 1951 2,622,193 Clayden Dec. 16, 1952 2,698,382 Uglow Dec. 28, 1954