Apparatus for producing continuous graphic displays from intermittantly sampled data

Apparatus for producing a graphic display of the variations in amplitude of a data signal, comprising

• first means connected to the source of the signal for deriving in successive periods two values, representing, respectively, the minimum value and the maximum value of said signal in each of said periods,
• said first means including means for producing and holding in each of said periods two output signals having respective values which represent, respectively, the minimum and the maximum excursions of the value of said data signal during that period, and
• second means connected to said first means for producing successive parallel line segments on a display medium during successive ones of said periods, each of said line segments being continuous and extending between two points, the positions of which represent, respectively, the minimum value and the maximum value of said signal derived during a previous one of said periods,
• said second means including
• generating means for producing a ramp signal the value of which sweeps progressively between first and second values once during each of said periods,
• comparing means connected to receive and to compare the value of said ramp signal, during each of said periods, and the value of each of said output signals as produced during a corresponding previous one of said periods, and to produce first and second logic signals at the respective times during each sweep of said ramp signal at which the value thereof achieves a predetermined relationship with the respective values of said two output signals, and
• circuit means including means connected to said comparing means and controlled by said logic signals to start the production of each of said line segments upon the production of said first logic signal during the corresponding one of said sweeps, and to stop the production of that line segment upon the production of said second logic signal during that sweep.

Apparatus for applying to a utilization device signals having values representing the minimum and the maximum excursions of the value of a data signal during each of consecutive ones of a series of periods, comprising

• switching means having alternate first and second states,
• means connected to said switching means to cause it to assume said first and second states alternately throughout respective consecutive ones of said periods,
• first and second measure and hold channels, each having an input arranged for connection to a source of a data signal and an output arranged for connection to a utilization device,
• means connecting said switching means to said channels to cause said first channel, when said switching means has said first state, and said second channel, when said switching means has said second state, to produce and hold first and second signals of respective values which represent the respective minimum and maximum values attained by said data signal during the corresponding ones of said periods, and concurrently to cause said second channel, when said switching means has said first state, and said first channel, when said switching means has said second state, to present in the corresponding one of said outputs said first and second signals of that channel from the immediately preceeding one of said periods, and thereafter to reset the values of the so-presented first and second signals to a datum value.