Apparatus for eliminating flicker in a driven display

Claim 1

A system for displaying the number of pulses counted by a display-driving counter during a time interval of interest as an illuminated digital representation thereof, the display being characterized as providing said illuminated representation when electrically excited beyond a predetermined threshold level, the system comprising, means for exciting the display with a periodic electrical signal having a first portion of amplitude less than said threshold level and a time duration at least equal to said time interval of interest, said signal having a second portion succeeding said first portion of amplitude at least equal to said threshold level, and means including an integrating means coupled to the exciting means for supplying timing pulses to said counter only during said time duration, said integrating means being synchronized to said first portion of said periodic electrical signal so that said counter counts the number of pulses received in said time interval while said display is extinguished by said first portion of said electrical signal.

Claim 2

A system for displaying the number of pulses counted by a display-driving counter during a time interval of interest as an illuminated digital representation thereof, the display being characterized as providing said illuminated representation when electrically excited beyond a predetermined threshold level, the system comprising, means for exciting the display with a periodic electrical signal having a first portion of amplitude less than said threshold level and a time duration at least equal to said time interval of interest, said signal having a second portion succeeding said first portion of amplitude at least equal to said threshold level, and means including an integrating means coupled to the exciting means for supplying timing pulses to said counter only during said time duration, said integrating means being synchronized to said first portion of said periodic electrical signal so that said counter counts the number of pulses received in said time interval while said display is extinguished by said first portion of said electrical signal.

Claim 3

A system for synchronizing the excitation of a display to a display-driving apparatus comprising, a source of a time-varying signal having a waveform portion for exciting the display to provide the desired output, monostable means including a storage circuit and characterized as having stable and unstable states and wherein the time during which said monostable means remains in the unstable state is determined at least in part by the time required to charge said storage circuit to a predetermined level, said monostable means assuming a stable state when said predetermined level is attained, means for changing the state of said apparatus coupled to said monostable means and controlled thereby such that said apparatus changes state when said monostable means is in the stable state, means coupling said source of time-varying signal to said storage circuit for charging said storage circuit at a rate controlled at least in part by said time-varying signal, the charging of said storage circuit to said predetermined level occurring substantially at the termination of said waveform portion of said time-varying signal, and means for applying the time-varying signal to the display so that the display is excited when said monostable means is in said unstable state.

Claim 4

A system for synchronizing the excitation of a display to a display-driving apparatus comprising, a source of a time-varying signal having a waveform portion for exciting the display to provide the desired output, monostable means including a storage circuit and characterized as having stable and unstable states and wherein the time during which said monostable means remains in the unstable state is determined at least in part by the time required to charge said storage circuit to a predetermined level, said monostable means assuming a stable state when said predetermined level is attained, means for changing the state of said apparatus coupled to said monostable means and controlled thereby such that said apparatus changes state when said monostable means is in the stable state, means coupling said source of time-varying signal to said storage circuit for charging said storage circuit at a rate controlled at least in part by said time-varying signal, the charging of said storage circuit to said predetermined level occurring substantially at the termination of said waveform portion of said time-varying signal, and means for applying the time-varying signal to the display so that the display is excited when said monostable means is in said unstable state.

Claim 5

A system for synchronizing the excitation of a display to a display-driving couNter comprising, a source of a time-varying signal having a first portion for exciting the display and a second portion for extinguishing the display a monostable device characterized as having stable and unstable states and wherein the time during which the device remains in the unstable state is determined at least in part by the time required to charge a capacitor to a predetermined level, said device assuming a stable state said predetermined level is attained, a source of timing pulses coupled to said counter, said device being coupled to said source to control the application of pulses to said counter such that said pulses are applied to said counter only when said device is in the stable state, means coupling said source to said capacitor for charging said capacitor at rates controlled at least in part by said time-varying signal, so tat the charging of said capacitor to said predetermined level occurs substantially at the termination of said first portion of said time-varying signal, and means for applying the time-varying signal to the display so that the display is excited by said first portion thereof when said device is in said unstable state.

Claim 6

A system for synchronizing the excitation of a display to a display-driving couNter comprising, a source of a time-varying signal having a first portion for exciting the display and a second portion for extinguishing the display a monostable device characterized as having stable and unstable states and wherein the time during which the device remains in the unstable state is determined at least in part by the time required to charge a capacitor to a predetermined level, said device assuming a stable state said predetermined level is attained, a source of timing pulses coupled to said counter, said device being coupled to said source to control the application of pulses to said counter such that said pulses are applied to said counter only when said device is in the stable state, means coupling said source to said capacitor for charging said capacitor at rates controlled at least in part by said time-varying signal, so tat the charging of said capacitor to said predetermined level occurs substantially at the termination of said first portion of said time-varying signal, and means for applying the time-varying signal to the display so that the display is excited by said first portion thereof when said device is in said unstable state.

Claim 7

The system as claimed in clam 3 wherein said means for charging said capacitor includes a resistor and wherein said capacitor and resistor form an integrator for said time-varying signal.