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Oscilloscopes

The oscilloscopes supported by IC-CAP are:

    • HP 54120T Series Digitizing Oscilloscopes
    • HP 54510 Digitizing Oscilloscope
    • Agilent Infiniium Oscilloscope
    • HP 54750 Series Digitizing Oscilloscopes

HP 54120T Series Digitizing Oscilloscopes

The HP 54120 Series of digitizing oscilloscopes measure time-domain responses, including TDR (time-domain reflectometry).

    • HP 54121T measures signals from DC through 20 GHz.
    • HP 54122T (does not have a step generator and cannot perform TDR measurements) provides programmable input attenuation. Bandwidth is reduced to 12.4 GHz due to the input attenuators.
    • HP 54123T operates up to 34 GHz; it operates up to 20 GHz on channel 1 (the channel on which the step generator is available).

IC-CAP assigns the following names to the units:

CHn    Channel Unit n (1, 2, 3, and 4)

A Setup configured for measurements using an HP 54120 Series is in the model file 54120.demo.mdl. See Appendix G, "54120 Demo" for additional information about this demonstration file. These files also include examples using an HP 54120 Series oscilloscope with an HP 8130 pulse generator and provides hints for obtaining good alignment between measured and simulated waveforms when a pulse generator is used.

The following instrument capabilities are supported by IC-CAP:

    • Time-domain measurements nested within DC bias settings provided by DC SMUs.
    • 4-channel concurrent data acquisition.
    • Offset, range, and probe attenuation adjustment for each channel. HP 54122T includes options to set internal attenuation for each channel (refer to Table 33).
    • Averaging of between 1 and 2048 waveform acquisitions on each channel.
    • Automatic Pulse Parameter Measurements, such as risetime and peak-to-peak voltage. These are requested in Outputs of Mode T. For help on the available choices, click the middle mouse button over the Pulse Param field and see the Status window.
    • Square-wave generation (except HP 54122T) on CH1, the left-most connector on the test set. Frequency can be adjusted from 15.3 Hz to 500 kHz. To activate the step generator, the Setup should include an Input with Mode V and Type TDR. In the absence of a type TDR Input, the step generator is not activated.

The instruments do not support some of the fields present in a TDR Input. For example, it is not possible for the instrument to offer other than a 50-ohm source impedance. The one field that is of consequence to oscilloscope measurements is Period. IC-CAP directs the instrument to use the closest value supported.

The other TDR Input fields are ignored during measurement, and the following hardware-imposed values of the instrument's step function apply:

    • Initial value of 0V
    • Pulsed value of 200 mV into 50 ohms; 400 mV into an open-circuit
    • Delay of approximately 17 nsec
    • Risetime of approximately 40 psec
    • Pulse width equal to about 50 percent of the specified period
    • Source impedance of 50 ohms
    • Time-Domain Reflectometry (except HP 54122T). When a type TDR Input is present in the Setup, the reflected signal is available on the unit designated CH1.

To make a time-domain measurement, a Setup must have these inputs and outputs:

    • An Input with Mode T and Type LIN. Here, the values of Start, Stop, and Number of Points govern the time axis of the measurement. Start and Stop values define the time viewing window, and are relative to the trigger event used by the oscilloscope.
    • Optionally, an Input of Mode V and Type TDR or PULSE. The Period field in this Input controls the rate of the oscilloscope's internal square-wave generator. If Period is set to 0, or if this Input is absent from the Setup, the oscilloscope's internal square-wave generator is not activated for the measurement. In this case, a trigger signal must be provided on the oscilloscope's trigger input.
If the Input's Unit field is set to ground, IC-CAP ignores the Input during the measurement. In this manner, measurements can be performed using a pulse generator controlled by its front panel. If the Input's Unit field is set to the pulse unit of a supported pulse generator (for example, PULSE1 for an HP 8130 generator), then IC-CAP will control the pulse generator to provide stimulus to the DUT and oscilloscope.

Refer to the HP 8130 Pulse Generator documentation provided with IC-CAP.

    • To capture a waveform from any of the instrument's 4 channels requires an Output of Mode V. The Output Editor permits you to specify from which channel a waveform is desired. Define an Output for each channel of interest.
    • To obtain automatically extracted pulse parameters at any of the 4 channels requires an Output of Mode T.
The following pulse parameters can be requested: DUTYCYCLE, FALLTIME, FREQ, OVERSHOOT, PERIOD, PRESHOOT, RISETIME, VPP, VRMS, +WIDTH, and -WIDTH. Consult the instrument's Front Panel Operation Reference for definitions of these parameters or information on the process by which the instrument computes them.

By defining multiple Outputs for a scope channel, it is possible to obtain both the full time-domain waveform and any number of automatically extracted pulse parameters for that channel, all in the same measurement. This can be done with any or all of the 4 channels within the same measurement.

The following table describes the HP 54120 series options and their default values, where applicable.

Table 33 HP 54120 Series Options 
Option
Description
Hold Time
 Time, in seconds, prior to performing time-domain measurement. Can be used to permit additional DC stabilization when a time-domain sweep is nested within DC steps provided by a DC bias unit. Default = 0
Averages
 Number of averages. Maximum = 2048. Default = 1
CH1 Offset†
 DC offset value of Channel 1 in volts. Does not directly affect waveforms returned from the oscilloscope. However, an improper setting can cause the instrument to fail when measuring pulse parameters, such as RISETIME. Set to a value close to the middle of the expected range of the output voltage waveform to maximize the instrument's ability to achieve high resolution without experiencing clipping. Valid range is ± 500mV · (CH1 Probe Attn) · (CH1 Internal Attn).
Default = 200.0mV
CH1 Probe Attn†
 Set to 10 if the channel 1 probe provides a divide by 10 functionality (20dB). Specifying the attenuation of the probe permits the oscilloscope to generate data in which the probe attenuation is corrected out. Values between 1 and 1000 are accepted. Default = 1.0
CH1 Internal Attn†
 HP 54122T only. This option causes IC-CAP to control attenuators inside the 54122 test set. The attenuators have limited power-handling ability††. Measured voltages will take the attenuation setting into account. Values 1, 3, 10, and 30 are valid. Default = 1.0
CH1 Range†
 Set in excess of the maximum anticipated signal swing for this channel. Does not affect waveforms returned from the oscilloscope. However, an improper setting can cause the instrument to fail when measuring pulse parameters, such as RISETIME. Specify a Range value between
CH1 Range†
(cont'd)
 8mV · (CH1 Probe Attn) · (CH1 Internal Attn) and
640mV · (CH1 Probe Attn) · (CH1 Internal Attn).
Default = 640.0 mV

Notes:
†   Option table entries are also provided for Offset, Probe Attn, Internal Attn, and Range on channels CH2, CH3, and CH4.
††Changing the Probe Attn options for CH1-CH4 and the trigger input does not attenuate the input signals. It only changes the results reported by the instrument. To deliver signals exceeding 2V DC or 16 dBm AC peak, use an external attenuator.
    By using the internal attenuators of the HP 54122T (via the Internal Attn options), larger voltages can be accepted. Limitations on attenuator voltage and power handling are described in the Internal Atten documentation in the Channels Menu chapter of the HP 54122T Front Panel Reference.

Note


The external trigger is ignored if a TDR type Input is defined in the Setup. In the presence of a TDR type Input, the scope is triggered by its internal TDR step generator.

The TRG options listed in the following table apply when driving the trigger input of the oscilloscope with an external signal. This is typically done with the trigger output from a signal generator.

Table 34 Trigger Options for the HP 54120T Series 
Option
Description
TRG Probe Attn
 Set to 10 if the trigger probe is fitted with a 10X (20dB) divider. Values between 1 and 1000 are accepted. Default = 1.0
TRG Slope
 Specify triggering on a rising (+) or falling (-) edge. Default = +
TRG Level
 Voltage threshold at which triggering occurs. Valid range is
±1V · (TRG Probe Attn). Default = 100.0mV
Normalize TDR
 If Yes, TDR waveform data from CH1 is subject to the HP 54120 series reflection normalization process. This can substantially improve waveform integrity when cabling and test fixtures have impedance mismatches. Prior to using this option perform calibration of the network reflection path via the front panel Network page. Default = No
(This option is not supported by the HP 54122.)
Delay for Timeouts
 For long-running measurements (that use a high number of averages, for example) use this option to avoid measurement timeouts. Default=0
Init Command
 Command field to set the instrument to a mode not supported by the option table. This command is sent at the end of instrument initialization for each measurement. Normal C escape characters such as \n (new line) are available. Default = none

HP 54510 Digitizing Oscilloscope

The HP 54510 is a 1 giga-sample/second, 2-channel digitizing oscilloscope. The HP 54510 driver is an example of a driver created using the Open Measurement Interface. The driver's source code can be found in the files user_meas3.hxx and user_meas3.cxx in the directory $ICCAP_ROOT/src. For information, refer to Chapter 2, "Drivers."

IC-CAP assigns the following names to the units:

CHn    Channel Unit n (1 and 2)

The following instrument capabilities are supported by IC-CAP:

    • Time-domain measurements nested within DC bias settings provided by DC SMUs.
    • 2-channel concurrent data acquisition.
    • Offset, range, and probe attenuation adjustment for each channel. (Refer to Table 35.)
    • Averaging 1 to 2048 waveform acquisitions on each channel.
    • Automatic Pulse Parameter Measurements, such as risetime and peak-to-peak voltage. These are requested in Outputs of Mode T. For help on the available choices, click the middle mouse button over the Pulse Param field and see the Status window.

To make a time-domain measurement, a Setup must contain these Inputs and Outputs:

    • An Input with Mode T and Type LIN. Here, the values of Start, Stop, and Number of Points govern the time axis of the measurement. Start and Stop values define the time viewing window, and are relative to the trigger event used by the oscilloscope. The HP 54510 driver uses the repetitive sampling mode and therefore always measures 501 points. The timebase range is set to 500 × step size of the input sweep. The timebase requires a value in the sequence 1-2-5, that is, 1 nsec, 2 nsec, 5 nsec, 10 nsec, ... , 1 sec, 2 sec, or 5 sec. If the Input step size does not correspond to a valid timebase, the driver aborts the measurement and recommends new stop and step values for the input sweep.
    • Optionally, an Input of Mode V and Type PULSE. A trigger signal must be provided on the oscilloscope's trigger input. If the Input Unit field is set to ground, IC-CAP ignores the Input during the measurement. In this manner, you may perform measurements using a pulse generator controlled by its front panel. If the Input Unit field is set to the pulse unit of a supported pulse generator (for example, PULSE1 for an HP 8130 generator), then IC-CAP will control the pulse generator to provide stimulus to the DUT and oscilloscope. For more information, refer to HP 8130 Pulse Generator. Also refer to the documentation for the HP 54120 in the 54120.demo.mdl file as well as Appendix G, "54120 Demo."
    • To capture a waveform from either of the instrument's 2 channels requires an Output of Mode V. The Output Editor permits you to specify from which channel a waveform is desired. Define one such Output for each channel of interest.
    • To obtain automatically extracted pulse parameters at either of the 2 channels, the Setup must include an Output of Mode T.
The following pulse parameters can be requested: DUTYCYCLE, FALLTIME, FREQ, OVERSHOOT, PERIOD, PRESHOOT, RISETIME, VPP, VRMS, +WIDTH, and -WIDTH. Consult the instrument's Front Panel Operation Reference for definitions of these parameters, or information on the process by which the instrument computes them.

By defining multiple Outputs for a scope channel, both the full time-domain waveform and any number of automatically extracted pulse parameters for that channel can be obtained, all in the same measurement. This can be done with either or both of the channels in the same measurement.

The following table describes the HP 54510 options and default values, where applicable.

Table 35 HP 54510 Options 
Option
Description
Hold Time
 Time, in seconds, prior to performing time-domain measurement. Can be used to permit additional DC stabilization when a time-domain sweep is nested within DC steps provided by a DC bias unit. Default = 0.0
Averages
 Number of averages. Maximum = 2048. The HP 54510 rounds the number of averages to the nearest power of 2. If the value is exactly halfway between, it takes the higher value. Default = 1
CH1 Offset†
 DC offset value of Channel 1, in volts. This does not directly affect waveforms returned from the oscilloscope. However, an improper setting can cause the instrument to fail when measuring pulse parameters, such as RISETIME. Set this to a value close to the middle of the expected range of the output voltage waveform; this will maximize the instrument's ability to achieve high resolution without experiencing clipping. Valid range is ±250V • (CH1 Probe Attn). Default = 0.0
CH1 Probe Attn†, ††
 Set to 10 if the Channel 1 probe provides a divide by 10 functionality (20 dB) and 50 ohm input impedance is selected. Specifying the attenuation of the probe permits the oscilloscope to generate data in which the probe attenuation is corrected out. Values between 0.9 and 1000 are accepted.
Default = 1.0
CH1 Range†
 Set in excess of the maximum anticipated signal swing for this channel. This option does not affect waveforms returned from the oscilloscope. However, an improper setting can cause the instrument to fail when measuring pulse parameters, such as RISETIME. Default = 2.0

Notes:
†   Option table entries are also provided for Offset, Probe Attn, and Range for CH2.
††Changing Probe Attn options for CH1, CH2 and the External Trigger input does not attenuate the input signals. It only changes the results reported by the instrument. To deliver signals exceeding 5V rms (50 ohm) or 250V (1 Mohm), an external attenuator should be used.

Refer to the following table for oscilloscope trigger options. The TRG/TRIG options apply to the trigger input. This is typically done with the trigger output from a signal generator. When using the EXT TRIG channel, be sure the TRG Source option is set to "E" (External Trigger).

Note


Instrument settings not included in the Instrument Options folder, such as input impedance, can be set manually before executing Measure.

Table 36 Oscilloscope Trigger Options for the HP 54510 
Option
Description
EXT TRIG Attn
 Attenuation of the EXT TRIG channel. Set to 10 if the trigger probe is fitted with a 10X (20dB) divider and the EXT TRIG channel is set to 50 ohms. Values between 0.9 and 1000 are accepted. Default = 1.0
TRG Source
 Specify the trigger source channel: 1 (CH1), 2 (CH2) or
E (External Trigger). Default = E
TRG Slope
 Specify + (rising edge) or - (falling edge). Default = +
TRG Level
 Voltage threshold at which triggering occurs. Valid range is
±2V • (TRG Probe Attn) for the EXT TRIG channel and
±1.5 • (full scale from center of screen) for channels CH1 and CH2.
Default = 0.0
Delay for Timeouts
 For long-running measurements (that use a high number of averages, for example), use this option to avoid measurement timeouts.
Default = 0.0
Init Command
 Use to set the instrument to a mode not supported by the option table. This command is sent at the end of instrument initialization for each measurement. Normal C escape characters such as \n (new line) are available. Default = none

Agilent Infiniium Oscilloscope

The Agilent Infiniium scopes are available as 2 or 4-channel digitizing oscilloscopes. IC-CAP supports the following Infiniium scopes:

    • 54810A, 54815A, 54820A, 54825A 500 MHz bandwidth, 1 GSa/s sample rate and 32K of memory width.
    • 54835A, 1 GHz bandwidth, 4 GSa/s sample rate, 62K memory width.
    • 54845A, 1.5 GHz bandwidth, 8 GSa/s sample rate, 64K memory width.

The IC-CAP driver supports acquisition only from Channels 1 and 2.

IC-CAP assigns the following names to the units:

CHn    Channel Unit n (1 and 2)

The following instrument capabilities are supported by IC-CAP:

    • Time-domain measurements nested within DC bias settings provided by DC SMUs.
    • 2-channel concurrent data acquisition (Channel 1 and 2 only).
    • Offset, range, and probe attenuation adjustment for each channel. (Refer to Table 37.)
    • Averaging 1 to 2048 waveform acquisitions on each channel.
    • Automatic Pulse Parameter Measurements, such as risetime and peak-to-peak voltage. These are requested in Outputs of Mode T. For help on the available choices, click the middle mouse button over the Pulse Param field and see the Status window.

To make a time-domain measurement, a Setup must contain these Inputs and Outputs:

    • An Input with Mode T and Type LIN. Here, the values of Start, Stop, and Number of Points govern the time axis of the measurement. Start and Stop values define the time viewing window, and are relative to the trigger event used by the oscilloscope. The Infiniium acquisition range is given by the number of acquisition points multiplied by the sampling period (1/Acquisition Rate). Acquisition points and frequency are set in the instrument option table. If the time viewing window set by the Start and Stop values is wider than the acquisition range, the driver aborts the measurement. The Acquisition rate must be in the 1, 2.5, 5, 10 sequence, that is, 1MSa/s, 2.5 MSa/s, 5 MSa/s, etc. The maximum acquisition rate depends on the scope model. The acquisition mode may be Real or Equivalent Time. Real time mode usually is used for single events, such as transients, while equivalent time may be used for periodic signals.
    • Optionally, an Input of Mode V and Type PULSE. A trigger signal must be provided on the oscilloscope's trigger input. If the Input Unit field is set to ground, IC-CAP ignores the Input during the measurement. In this manner, you may perform measurements using a pulse generator controlled by its front panel. If the Input Unit field is set to the pulse unit of a supported pulse generator (for example, PULSE1 for an HP 8130 generator), then IC-CAP will control the pulse generator to provide stimulus to the DUT and oscilloscope. For more information, refer to HP 8130 Pulse Generator.
    • To capture a waveform from either of the instrument's 2 channels requires an Output of Mode V. The Output Editor permits you to specify from which channel a waveform is desired. Define one such Output for each channel of interest. When acquisition range and points differ from sweep time interval and points, the waveform is actually interpolated by the actual measured data. It is a good practice to use an acquisition range that is slightly greater than the time window, but not too much greater.
    • To obtain automatically extracted pulse parameters at either of the 2 channels, the Setup must include an Output of Mode T.

The following pulse parameters can be requested: DUTYCYCLE, FALLTIME, FREQ, OVERSHOOT, PERIOD, PRESHOOT, RISETIME, VPP, VRMS, +WIDTH, and -WIDTH. Consult the instrument's Front Panel Operation Reference for definitions of these parameters, or information on the process by which the instrument computes them.

By defining multiple Outputs for a scope channel, both the full time-domain waveform and any number of automatically extracted pulse parameters for that channel can be obtained, all in the same measurement. This can be done with either or both of the channels in the same measurement.

As shown in the following instrument options table, the trigger source may be set to Channel 1 or 2, or to EXT or AUX. The trigger sweep may be Auto, Triggered or Single. Trigger level and slope are also specified.

The following table describes the Infiniium options and default values, where applicable.

Table 37 Infiniium Options 
Option
Description
Hold Time
 Time, in seconds, prior to performing time-domain measurement. Can be used to permit additional DC stabilization when a time-domain sweep is nested within DC steps provided by a DC bias unit. Default = 0.0
Sample Rate
 The internal sample frequency. It must be in the 1, 2.5, 5, 10 sequence. In real-time mode the maximum sample rate is 1 GSa for the 54810A/15A, 2GSa for the 54820A/25A, 4 GSa for the 54835A and 8 GSa for the 54845A (2 channel mode). Default = 1 GSa.
Acquisition
Mode
 Can be real time (R) or equivalent time (E). Real time is used for single events such as transients while equivalent time may be used to increase the "equivalent" sampling rate when the waveform is periodical. Default = R.
Acquisition
Count
 Turns averaging on or off, and (when on) sets the number of averages. Allowed range is 1 through 4096. Use 1 to turn averaging off. Use 2 through 4096 to turn on averaging and set the count. Default = 1.
Acquisition
Points
 Number of acquired points at the sample rate. The acquisition range is defined as the acquisition period 1/(Sample rate) multiplied by the number of points. The number of points is limited by the memory depth: 32,768 points for the 54810A/15A/20A/25A and 65,536 points for the 54835A/45A.
CH1 Scale†
[V/div.]
 DC vertical sensitivity in Volts per division. When probe attenuation is 1 maximum sensitivity is 5 V/div. Minimum sensitivity is 1 mV/div for 54810A/15A/20A/25A and 2 mV/div for 54835A and 54845A. Default = 500 mV/div.
CH1 Offset†
[V]
 DC available offset. It depends on the scale. Maximum offset is ±250V when CHn Scale = 5 V/div.
CH1 Input†
 Channel input impedance: DC 50 ohm (DC50),1 Mohm (DC), AC. LFR1 and LFR2 are also possible when using the Agilent 1153A differential probe.
Default is DC.
CH1 Probe Attn†
††
 Set to 10 if the Channel 1 probe provides a divide-by-10 functionality (20 dB) and 50 ohm input impedance is selected. Specifying the attenuation of the probe permits the oscilloscope to generate data in which the probe attenuation is corrected out. Values between 0.9 and 1000 are accepted. Default = 10.0.
Trigger Input
Set trigger input source (1, 2, AUX or EXT). Default is 1 for Channel 1.
Trigger Sweep
 Set trigger sweep Modes to Auto (A), Triggered (T), or Single (S). Default is Auto (A).
Trigger Slope
 The only supported trigger mode is Edge. Trigger slope may be positive (+) or negative (-). Default is positive (+).
Trigger Level [V]
 Sets voltage level at which trigger occurs. Level range depends on sweep mode and scope type. Default is 500 mV.
Delay for Timeouts
 For long-running measurements, such as collecting a high number of averages, use this option to avoid measurement timeouts. Default = 0.0
Init Command
 Sets the instrument to a mode not supported by the option table. This command is sent at the end of instrument initialization for each measurement. Normal C escape characters such as \n (new line) are available. Default = none

Notes:
†   Option table entries are also provided for Scale, Offset, Input and Probe Attn, for CH2.
††Changing Probe Attn options for CH1, CH2 and the External Trigger input does not attenuate the input signals. It only changes the results reported by the instrument. To deliver signals exceeding 5V rms (50 ohm) or 250V (1 Mohm), an external attenuator should be used.

HP 54750 Series Digitizing Oscilloscopes

The IC-CAP driver for the HP 54750 supports the following plug-in modules:

    • HP 54753A. This module is a 2-channel vertical plug-in with a TDR step generator built into channel one. The bandwidth of the TDR/vertical channel is 18 GHz. The bandwidth of channel 2 is 20 GHz.
    • HP/Agilent 54754A. This module has 2 independent vertical channels and 2 independent step generators. The bandwidth of both channels is 18 GHz.
    • HP 54752A and HP 54752B. The 54752A has two 50 GHz bandwidth channels and 54752B provides a single cost-effective channel.
    • HP 54751A. This module has two 20 GHz bandwidth channels.

Since the instrument is configurable, the insertion of the instrument in the active instrument table must be done using rebuild active list. Plug-in modules must be placed starting from slot 1 without discontinuities. IC-CAP assigns the following names to the units:

    • TDRn for TDR channels
    • CHn for normal scope acquisition channels

Example files: A Setup configured for measurements using the HP 54750, is in the model file /examples/model_files/misc/hp54750.mdl.

The following instrument capabilities are supported by IC-CAP:

    • Time domain acquisition for each channel (TDR or CH).
    • Offset, Scale, and Probe Attenuation adjustment for each channel.
    • Averaging of between 1 and 4096 waveform acquisition.
    • Automatic Pulsed/Waveform parameter measurements for each TDR or CH type channel.
    • Trigger Probe Attenuation, Slope, Level, Mode as well as the trigger slot (2 or 4 in case 2 plug-ins are present) can be set in the instrument table.
    • Start time, Stop time, and number of points are set in the Input Time sweep.
    • Step generator on TDR channels. Frequency rate can be adjusted between 50 and 250 kHz. To activate the step generator the setup should include an Input with mode V and Type TDR. Note that only one TDR step generator can be active per setup (differential TDR is not supported). The period on the TDR input is used to calculate frequency for TDR/TDT measurements.
    • TDR normalized measurements are supported for each of the TDR channels. To acquire a normalized TDR response, perform either software or hardware calibration, then set Normalize to Y in the TDR channel and measure. To perform software TDR calibration, first set the normalization option to TDR, then run Calibrate and follow the steps.
    • TDT normalized measurements are supported for each plug-in. Plug-in channel 1 must be the TDR source, and channel 2 must be the TDT sink. To acquire a normalized TDT measurement on channel 2, perform either software or hardware TDT calibration, then set Normalize to Y on channel 2 (sink) and measure. To perform software TDT, set the normalization option to TDT, run Calibrate, and follow the steps.

You must be sure to insert the oscilloscope into IC-CAP's instrument table. Connect the instrument, switch it on, and perform Rebuild in the Hardware Setup. The HP 54750 should be now present in the Instrument List. Select HP 54750 in the list and select Configure. The units should reflect the hardware configuration and the plug-in type in the Unit Table. Here are examples of what should appear in the table:

    • If module HP/Agilent 54754 occupies slots 1 and 2, TDR1 and TDR2 units should appear in the Unit Table.
    • If module HP 54753 occupies slots 1 and 2, TDR1 and CH2 units should appear in the Unit Table.

To make time-domain measurements (acquisition only), a setup must contain these Inputs and Outputs:

    • An Input with Mode T, and Type LIN. Minimum start time is 20 nsec; max start time is 10 sec. The minimum time range is 100 psec while the maximum range is 10 sec. During acquisition (no internal TDR) the number of acquired points can be set to any number between 16 and 4096.
    • A trigger signal must be provided at the trigger input (slot 2 or 4) to acquire any waveform. Trigger Mode can be selected in the instrument option. Use trigger mode FREErun or TRIGgered for periodic waveforms. Use option TRIGgered when using external trigger for example for acquiring transients or when using external TDR step generator.
    • To capture a waveform, an Output of Mode V is required. Define an output for each channel of interest.
    • To obtain automatically-extracted pulse parameters, the setup must include an output of mode T that specifies the unit and the requested parameter. Examples of parameter values are VPP and VRMS.

To make TDR or TDT measurements, a setup must contain these Inputs and Outputs:

    • An Input with Mode T and Type LIN. Minimum start time is 20 nsec, max start time is 10 sec. The minimum time range is 100 psec while the maximum range is 10 sec. When the instrument's Normalize option is turned OFF, the number of acquired points can be set to any number between 16 and 4096. When the Normalize option is ON, the number of points can be set to any number between 16 and 4096 that is a multiple of 2, such as 512 or 1024.
    • An Input with Mode V and Sweep Type TDR. The unit is set to the TDR source channel. Only the value of the Period is used during measurement for setting the frequency of the internal step generator. Use a value between 50 Hz (20 msec) and 250 kHz (4 usec). The other fields, such as Delay and Width, are used only by the simulator. If an external TDR step generator is used, then Unit must be set to GND, and all parameters (including Period) are used only by the simulator.
    • To capture the output waveforms, insert 1 or 2 Outputs of mode V referring to the TDR source channel for TDR measurements, or to the sink channel for TDT measurements.
    • (Optional). To measure waveform parameters such as VPP and RISETIME, insert 1 or more Outputs of mode T.

TDR or TDT measurements can be done with or without normalization. Normalization establishes a reference plane different from the oscilloscope output. The reflection and ohm measurements are based on the actual measured step height. Also, from this information, the scope builds a filter, which can be applied to any reflected signal. The risetime of the filtered step can be selected. The filtered step removes any losses or discontinuities from the reference plane generated by the plug-in.

To measure without normalization, simply set the Normalize flag to N in the instrument options for any channel involved in the TDR or TDT measurement.

To make normalized TDR measurements, either hardware or software normalization must be performed prior to measurement. To perform software calibration, set the Normalization mode to TDR in the Instrument Option Table. Then run Calibrate. This routine will load current sweeps (start, stop and period) in the instruments and then will ask the operator to insert the calibration standards (short and load) at the reference plane.

Once the instrument has been successfully calibrated, set the Normalize flag of the TDR source channel to `Y' before running a measurement to acquire normalized data. Set the normalized response Unit to VOLT (default), REF or OHM in the Instrument Options Table. When setting response scale to VOLT, IC-CAP will acquire the actual normalized response. When the response scale is OHM, IC-CAP will acquire the normalized-to-50 ohm response. This is particularly useful when evaluating characteristic impedance of different line series. Setting the scale to REF will acquire the reflection due to a change of impedance. The normalized rise time can also be set in the instrument option table. The minimum settable rise time actually depends on the number of points. Generally speaking, increasing the number of points allows a smaller rise time and therefore improves the space resolution (minimum distance between 2 discontinuities to distinguish them in the space/time domain).

To make normalized TDT measurements, either hardware or software normalization must be performed prior to measurement. To perform software calibration, set Normalization mode to TDT in the Instrument Option Table. Then connect source and sink together (without DUT) and run Calibrate.

Once the instrument has been successfully calibrated, set the Normalize flag of the TDT sink channel to `Y' before running a measurement to acquire normalized data. Normalized Response unit can be set to VOLT (default) or GAIN. The normalize risetime can also be varied with the same limitation described above.

Differential TDR/TDT Capability

New addition to TDR driver: Differential TDR/TDT capabilities.

Two new entries have been added to the Agilent 54750 Instrument table:

Differential Mode

Set the instrument in differential mode.

Channel 1 and 2 are the TDR channels.

The differential stimulus on channel 1 and 2 can be Differential (DIFF) or Common (COMM).

Default is no differential stimulus (NONE).

Once the instrument has been calibrated in differential Response mode, the response reading can be set to Differential (DIFF) Mode or Common (COMM).

Note that this field is active only when the Normalize Flag of the response channels is set to yes.

Default is DIFF.

To make TDR differential measurements, place the Agilent 54754A plug-in in the first 2 instrument slots (channel 1 and 2).

In the IC-CAP measurement page insert 1 input of type TDR (Unit TDR1 or CH1).

Insert 1 input of Mode T (Type LIN) and set the time interval and the number of points.

Insert 2 outputs of Mode V monitoring channel 1 and 2.

In the 54750 Instrument Option Table, set the Differential Mode to DIFF or COMM.

To measure raw data simply set the Normalize flags of CH1 and CH2 to N and run the measurements.

To measure normalized data, perform the TDR normalization before running the measurements. Follow the instructions in the 54754 manual to calibrate in differential TDR mode.

Once the instrument has been successfully calibrated, set the Normalize Mode to TDR, set Differential Response Mode to DIFF or COMM. To measure the normalized response simply set the Normalize flag of channel 1 and 2 to yes.

Summary differential TDR

Differential Mode
Differential Response Mode
Response Mode
CH1
CH2
Raw
DIFF/COMM
 Not Relevant
 Nor relevant
 N
 N
Norm
DIFF/COMM
 DIFF/COMM
 TDR
 Y
 Y

To make TDT differential measurements place 1 Agilent 54754A plug-in in the first 2 instrument slots (channel 1 and 2) and second 54754 plug-in in the third and fourth slots. When measuring differential TDT, the driver assumes that Channel 1 and 2 supply the differential stimulus (input).

In the IC-CAP measurement setup page insert 1 input of type TDR (Unit TDR1 or CH1).

Insert 1 input of Mode T (Type LIN) and set the time interval and the number of points.

Insert 4 outputs of Mode V monitoring channel 1 to 4. In the 54750 Instrument Option Table, set the Differential Mode to DIFF or COMM.

To measure raw data simply set the Normalize Flags of CH1,CH2,CH3 and CH4 to N and run the measurements.

To measure normalized data, the user needs to perform the TDT normalization before running the measurements.

Follow the instructions in the 54754 manual on how to calibrate in differential TDT mode.

Once the instrument has been successfully calibrated, set the Normalize Mode to TDT, set Differential Response Mode to DIFF or COMM.

To measure the normalized response simply set the normalized flag of channels 3 and 4 to yes.

Summary differential TDT:

Differential Mode
Differential Response Mode
Response Mode
CH1
CH2
CH3
CH4
Raw
DIFF/COMM
 Not Relevant
 Not relevant
 N
 N
 N
 N
Norm
DIFF/COMM
 DIFF/COMM
 TDT
 N
 N
 Y
 Y

The following table describes the HP 54750 options and default values, where applicable.

Table 38 HP 54750 Options Table 
Option
Description
Hold Time
 Time, in seconds, prior to performing time-domain measurements. Default = 0
Averages
 Number of averages per sample. Min = 1 (off), Max = 4096. Default = 16
Normalization Mode
 Two modes supported for calibration and measurements: TDR or TDT.
Default = TDR
Normalized Response Unit
 Sets the type of unit for the acquired normalized response. Possible choices are VOLT, REF or OHM for TDR type measurements and VOLT or GAIN for TDT measurements. Default = VOLT
Normalized Response Risetime
 Set the risetime for the normalized response. Minimum risetime depends on number of points. In case specified rise time is greater than the minimum allowed for that number of points, IC-CAP will set the minimum possible value. Default = 40 psec
CHn Probe Attenuation
 Probe Input impedance is always 50 ohm. Specifying the attenuation of the probe permits the oscilloscope to generate data in which the probe attenuation is corrected out. For example, set it to 10 if the channel 1 probe provides a divide by 10 functionality. Values between 0.9 and 1000 are accepted.
Default = 1.0
CHn Offset
 DC offset value of Channel 1, in volts. This does not directly affect waveforms returned from the oscilloscope. However, an improper setting can cause the instrument to fail when measuring pulse parameters, such as RISETIME. Set this to a value close to the middle of the expected range of the output voltage waveform; this will maximize the instrument's ability to achieve high resolution without experiencing clipping. Valid range is ±250V. Default = 200.0 mV
CHn Scale
 Default = 100.0 mV/div.
CHn Normalize
 Normalization Flag. When set to `Y', IC-CAP acquires the normalized response with unit as specified in The Normalized Response Unit. Default = N
TRG Probe Attenuation
 Default = 1.0
TRG Slope
 Specifies triggering on a rising (+) or falling (-) edge. Default = +
TRG Level
 Voltage threshold at which triggering occurs. Range depends on attenuation. Default = 0.0 mV
TRG Slot
 Choose the input trigger channel. For example, when 54754 plug-in is present on slot 1 and 2, trigger will be on slot 2. When another TDR plug-in is present on slot 3 and 4, slot 4 is another possible choice for trigger. Default = 2
TRG Mode
 Used when acquiring a waveform not in TDR mode (internal trigger is used in that case). Possible choices are freerun (FREE) usually used for periodic waveform or triggered (TRIG) for transients. Default = FREE
Delay for timeout
 Increase this delay when acquiring a large number of points or averages. This gives more time for the instrument to digitize the waveform and save it into memory. Default = 3
Init Command
 Use to set the instrument to a mode not supported by the option table. This command is sent at the end of instrument initialization for each measurement. Normal C escape characters such as \n (new line) are available. Default = None

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