Waveform comparison and display system using cathode ray tube

Claim 2

A waveform comparison and display system using a cathode ray tube comprising, input terminal means for receiving an input signal; digital memory means connected to said input to terminal means for sequentially storing levels of said input signal in digital quantities and for reading out the stored contents under control of clock pulses to provide an analog readout signal; switch means connected to said input terminal means and said digital memory means for switching said input signal and said analog readout signal at a high speed; display means connected to said switch means for displaying the switched two waveforms on the cathode ray tube; control means connected to said digital memory means and said display means for controlling the storing operation of said digital memory means and the sweep operation of said display means by a trigger signal synchronized with said input signal and for start-stop controlling the generation of said clock pulses in synchronism with the sweep operation of said display means, so that the switched two waveforms are displayed on the screen of said cathode ray tube in such a manner that the two waveforms are stationary with respect to each other.

Claim 3

A waveform comparison and display system using a cathode ray tube according to claim 1, further including means for synchronizing said switching of said switch means with said clock pulses.

Claim 4

In an oscilloscope having a cathode ray tube for visually displaying a pattern, the combination comprising: input means for receiving an input signal; controlled digital memory means responsive to clock pulses for storing a sequence of digital values representative of an input signal applied to said input means and for reading out an analog signal having values equal to the sequence of stored digital values under control of the clock pulses; vertical control means for controlling the vertical dimensions of the cathode ray tube pattern in response to signals applied to said vertical control means; switching means connected to said input means and said controlled digital memory means for alternately applying the input signal and the signal read-out from said digital memory means at a frequency substantially higher than a horizontal sweep frequency at which said cathode ray tube is operated to simultaneously display the waveform of the input signal and the waveform of the signal read out from the controlled digital memory means in a chopped mode; triggered horizontal sweep control means for controlling the horizontal sweep of the cathode ray tube; triggering means connected to said input means for triggering operation of said triggered horizontal sweep control means in response to said input signal; and clock pulse generating means responsive to operation of said triggered horizontal sweep control means for generating and applying the clock pulses to said controlled digital memory means only during a horizontal sweep period of said triggered horizontal sweep control means to display the waveform of the signal read out from said controlled digital memory means stationary with respect to the displayed input signal waveform.

Claim 5

In an oscilloscope having a cathode ray tube for visually displaying a pattern, the combination comprising: input means for receiving an input signal; controlled digital memory means responsive to clock pulses for storing a sequence of digital values representative of an input signal applied to said input means and for reading out an analog signal having values equal to the sequence of stored digital values under control of the clock pulses; vertical control means for controlling the vertical dimensions of the cathode ray tube pattern in response to signals applied to said vertical control means; switching means connected to said input means and said controlled digital memory means for alternately applying the input signal and the signal read-out from said digital memory means at a frequency substantially higher than a horizontal sweep frequency at which said cathode ray tube is operated to simultaneously display the waveform of the input signal and the waveform of the signal read out from the controlled digital memory means in a chopped mode; triggered horizontal sweep control means for controlling the horizontal sweep of the cathode ray tube; triggering means connected to said input means for triggering operation of said triggered horizontal sweep control means in response to said input signal; and clock pulse generating means responsive to operation of said triggered horizontal sweep control means for generating and applying the clock pulses to said controlled digital memory means only during a horizontal sweep period of said triggered horizontal sweep control means to display the waveform of the signal read out from said controlled digital memory means stationary with respect to the displayed input signal waveform.

Claim 6

In an oscilloscope according to claim 3, wherein said controlled digital memory means is comprised of: an analog-to-digital converter connected to said input means for developing a sequence of digital valued signals representative of the values of the input signal; a digital memory for storing and for reading out the sequence of digital valued signals developed by said analog-to-digital converter; a digital-to-analog converter connected to said digital memory and said switching means for converting the sequence of digital valued signals read out from said digital memory into an analog signal having values equal to the sequence of digital valued signals and for applying the analog signal to said switching means; and control means responsive to the operation of said triggered horizontal sweep control means and responsive to the clock pulses for applying the output from said analog-to-digital converter to said digital memory to store said digital values in said digital memory and for applying the clock pulses to said digital memory to read out the stored digital values during and in synchronism with the operation of said triggered horizontal sweep control means.

Claim 7

In an oscilloscope according to claim 3, wherein said switching means is responsive to an external signal for switching in response to the external signal; and further comprising means for applying the clock pulses to said switching means to operate said switching means in response to the clock pulses.