Dynamic time/voltage test system

Claim 2

A test system for a unit under test adapted for operation in combination with a repetitive pulse waveform source providing a sync pulse and a reference pulse to the system, and a stimuli pulse to the unit under test and in response thereto an output waveshape to the system; said system adapted for measuring the voltage level of the output waveshape at a specific time with respect to a reference point in time when said system operates in a voltage mode and the time required with respect to a reference point in time for the output waveshape to reach a specific voltage level when said system operates in a time mode; said system also being adapted to be automatically operated by programmable control means, said system comprising: a time window delay circuit responsive to said sync pulse source providing at its output a triggering pulse; a first source of reference potential whose output is connected to said time window delay circuit for controlling the time delay of said time window delay circuit; pulse-shaping means responsive to the triggering pulse of said time window delay circuit for establishing a time window starting with said reference point in time and a time period during which a measurement on an output waveshape can be made; generator means for producing a strobe pulse; delay means connected between said pulse shaper and said strobe generator to control the time of occurrence of said strobe pulse within said time window; a voltage sampler including a tunnel diode discriminator for measuring the amplitude of said output waveshape at the time said strobe pulse occurs, means for applying a bias signal to said discriminator, means for applying said strobe pulse to said discriminator, means for applying said output waveshape to said discriminator, means for applying said reference pulse to said discriminator, and a feedback loop; a second source of reference potential whose output establishes the time selected for a voltage measurement when said system operates in a voltage mode and the voltage selected for a time measurement when said system operates in a time mode; means for routing said second reference potentiaL source to said strobe delay means when said system operates in a voltage mode and to said bias signal application means when said system operates in a time mode; means for connecting said feedback loop to said bias application means when said system is operating in a voltage mode and to said strobe delay means when said system is operating in a time mode, the voltage in said feedback loop being proportional to the measurement desired, when at strobe occurrence the sum of strobe, output waveshape and bias signals equals the threshold level of said tunnel diode.

Claim 3

The invention defined by claim 1 including a countdown circuit having an input adapted for connection to the sync pulse source and an output connected to said time window delay circuit, said countdown circuit providing output pulses whose frequency is no greater than a prescribed maximum and to assure synchronization of said test system with said reference pulse and said output waveshape.

Claim 4

The invention defined by claim 2 including a third source of reference potential for preconditioning said voltage sampler close to its expected output and means for applying said preconditioning voltage to said feedback loop prior to sampling of said output waveshape.

Claim 5

The invention defined by claim 2 including means for sweeping said strobe pulse through said time window and means for maintaining in said feedback loop a voltage proportional to the maximum amplitude excursion of said output waveshape achieved during said voltage sweep.

Claim 6

The invention defined by claim 2 including means for operating said system in an oscilloscope mode, said oscilloscope mode means comprising means for attenuating the sawtooth output of an oscilloscope, said attenuated output being applied to sweep said strobe pulse through said time window in synchronization with the time base of said oscilloscope, and means for monitoring the output of said voltage sampler in the voltage mode with the vertical amplifier of said oscilloscope.

Claim 7

The invention defined by claim 1 including means for generating a calibration stimuli and a calibration signal whose relative time occurrences are fixed, and switch means for applying said triggering pulse to said strobe delay means and said output waveshape to said voltage sampler when said test system operates in a normal mode, and for applying said calibration stimuli to said strobe delay means in place of said triggering pulse and said calibration signal to said voltage sampler in place of said output waveshape when said system operates in a calibration mode to thereby detect time and voltage offsets occurring during normal operation of said test system.

Claim 8

The invention defined by claim 6 including means for reading said time offset, storing said time offset in digital form, generating an analog time offset correction voltage and applying said time offset correction voltage to said strobe delay means during normal operation of said test system.

Claim 9

The invention defined by claim 6 including means for reading said voltage offset, storing said voltage offset in digital form, generating an analog voltage offset correction voltage and applying said voltage offset correction voltage to said voltage sampler during normal operation of said test system.

Claim 10

The invention defined by claim 1 including means for generating a calibration stimuli and a calibration signal whose relative time occurrences are fixed, means for checking the time to voltage relationship of said strobe delay means, said checking means including a plurality of different delay standards and a plurality of relays for switching said delay standards in connection with said voltage sampler, and switch means for applying said triggering pulse to said strobe delay means and said output waveshape to said voltage sampler when said test system operates in a normal mode, and for applying said calibration stimuli to said strobe delay means in place of said triggering pulse and said calibration signal to said checking means in place oF said output waveshape when said system operates in a calibration mode.

Claim 11

A test system for a unit under test adapted for operation in combination with a repetitive pulse waveform source providing a sync pulse and a reference pulse to the system, and a stimuli pulse to the unit under test and in response thereto an output waveshape to the system; said system adapted for making multiple voltage level measurements on the output waveshape at specific times with respect to a reference point in time when said system operates in a voltage mode and the times required with respect to a reference point in time for the output waveshape to reach specific voltage levels when said system operates in a time mode; said system also being adapted to be automatically operated by programmable control means, said system comprising: a time window delay circuit responsive to said sync pulse source providing at its output a triggering pulse; a primary source of reference potential whose output is connected to said time window delay circuit for controlling the time delay of said time window delay circuit; pulse-shaping means responsive to the triggering pulse of said time window delay circuit for establishing a time window starting with said reference point in time and a time period during which measurements on an output waveshape can be made; first and second generator means for producing a first and second strobe pulse; first and second delay means connected between said pulse shaper and said first and second strobe generator to control the time of occurrence of said first and second strobe pulses within said time window; means for splitting said output waveshape; first and second voltage samplers, each including a tunnel diode discriminator for measuring the amplitude of said output waveshape at the time said strobe pulse occurs, means for applying a bias signal to said discriminator, means for applying said strobe pulse to said discriminator, means for applying said split output waveshape to said discriminator, means for applying said reference pulse to said discriminator, and a feedback loop; first and second secondary sources of reference potential whose output establishes the time selected for a voltage measurement when said system operates in a voltage mode and the voltage selected for a time measurement when said system operates in a time mode; means for routing said first and second secondary reference potentials to said first and second strobe delay means, respectively, when said system operates in a voltage mode and to said first and second bias signal application means when said system operates in a time mode; means for connecting said first and second feedback loop to said first and second bias application means, respectively, when said system is operating in a voltage mode, and to said first and second strobe delay means when said system is operating in a time mode, the voltage in said feedback loop being proportional to the measurement desired, when at strobe occurrence the sum of strobe, output waveshape and bias signals equals the threshold level of said tunnel diode; filtering means connected to said first and second feedback loops for reading the measurements made by said first and second voltage samplers; and, means for subtracting the measurements made by said first and second voltage samplers.

Claim 12

A test system for a unit under test adapted for operation in combination with a repetitive pulse waveform source providing a sync pulse and a reference pulse to the system, and a stimuli pulse to the unit under test and in response thereto an output waveshape to the system; said system adapted for making multiple voltage level measurements on the output waveshape at specific times with respect to a reference point in time when said system operates in a voltage mode and the times required with respect to a reference point in time for the output waveshape to reach specific voltage levels when said system operates in a time mode; said system also being adapted to be automatically operated by programmable control means, said system comprising: a time window delay circuit responsive to said sync pulse source providing at its output a triggering pulse; a primary source of reference potential whose output is connected to said time window delay circuit for controlling the time delay of said time window delay circuit; pulse-shaping means responsive to the triggering pulse of said time window delay circuit for establishing a time window starting with said reference point in time and a time period during which measurements on an output waveshape can be made; first and second generator means for producing a first and second strobe pulse; first and second delay means connected between said pulse shaper and said first and second strobe generator to control the time of occurrence of said first and second strobe pulses within said time window; means for splitting said output waveshape; first and second voltage samplers, each including a tunnel diode discriminator for measuring the amplitude of said output waveshape at the time said strobe pulse occurs, means for applying a bias signal to said discriminator, means for applying said strobe pulse to said discriminator, means for applying said split output waveshape to said discriminator, means for applying said reference pulse to said discriminator, and a feedback loop; first and second secondary sources of reference potential whose output establishes the time selected for a voltage measurement when said system operates in a voltage mode and the voltage selected for a time measurement when said system operates in a time mode; means for routing said first and second secondary reference potentials to said first and second strobe delay means, respectively, when said system operates in a voltage mode and to said first and second bias signal application means when said system operates in a time mode; means for connecting said first and second feedback loop to said first and second bias application means, respectively, when said system is operating in a voltage mode, and to said first and second strobe delay means when said system is operating in a time mode, the voltage in said feedback loop being proportional to the measurement desired, when at strobe occurrence the sum of strobe, output waveshape and bias signals equals the threshold level of said tunnel diode; filtering means connected to said first and second feedback loops for reading the measurements made by said first and second voltage samplers; and, means for subtracting the measurements made by said first and second voltage samplers.

Claim 13

The invention defined by claim 10 including a countdown circuit 71 having an input adapted for connection to the sync pulse source and an output connected to said time window delay circuit, said countdown circuit providing output pulses whose frequency is no greater than a prescribed maximum and to assure synchronization of said test system with said reference pulse and said output waveshape.

Claim 14

The invention defined by claim 11 including first and second tertiary sources of reference potential for preconditioning said first and second voltage samplers, respectively, close to their expected output and means for applying said preconditioning voltages to said first and second feedback loops, respectively, prior to sampling of said output waveshape.

Claim 15

The invention defined by claim 11 including first and second means for sweeping said first and second strobe pulses through said time window and means for maintaining in said first and second feedback loops a voltage proportional to the maximum amplitude excursion of said output waveshape achieved during said voltage sweep.

Claim 16

The invention defined by claim 10 including means for generating a calibration stimuli and a calibration signal whose relative time occurrences are fixed, and switch means for applying said triggering pulse to said first and second strobe delay means and said output waveshape to said first and second voltage samplers, respectively, when said test system operates in a normal mode, and for applying said calibration stimuli to said first and second strobe delay means in place of said triggering pulse and said calibration signal to said first and second voltage samplers in place of said split output waveshape when said system operates in a calibration mode to thereby detect time and voltage offsets occurring during normal operation of said test system.

Claim 17

The invention defined by claim 14 including means for reading said offset, storing said offset in digital form, generating an analog offset correction voltage and applying said offset correction voltage to said voltage sampler during normal operation of said test system.