Agilent Technologies 22A, 24A, 41A, 42A, 54621A, 54621D FFT Operation

5-27

Making Measurements

FFT Measurement

FFT Operation

1Press the Math key, press the FFT softkey, then press the Settings softkey

to display the FFT menu.

Source selects the source for the FFT. The source can be any analog cha nnel,

or math functions 1 + 2, 1 – 2, and 1 * 2.

Span set s th e o ve ral l w id th of the FFT sp ec tr um t ha t y ou s ee on th e di sp la y ( lef t

graticule to right graticule). Divide span by 10 to calculate the number of Hertz

per divisi on. It i s possibl e to set S pan abov e the max imum ava ilable f requenc y,

in which ca se the d isplayed spectru m will no t take up the whol e screen . Press

the Span softkey, then turn the Entry knob to set the desired frequency span of

the display.

Center sets the FFT spectrum frequency represented at the center graticule on

the d is pl ay. It i s p os si ble to se t t he C en te r t o va lu es be low ha lf th e sp an or ab ove

the maximum available frequency, in which case the displayed spectrum will

not take up the whole screen. Press the Center softkey, then turn the Entry

knob to set the desired center frequency of the display.

Preset sets the frequency Span and Center to valu es that will cause the entire

available spectrum to be displayed. The maximum available frequency is half

the effective FFT sample rate, which is a function of the time per division setting.

The current FFT sample rate is displayed above the softkeys.

Source

select Frequency

Span Return to

previous menu

Center

frequency Preset Span

and Center

frequencies

Vertical and

Window FFT

controls

Contents

Main The Oscilloscopes at a Glance In This Book Page Contents 3 Triggering the Oscilloscope Selecting Trigger Modes and Conditions 3-3 Trigger Types 3-11 The Trigger Out connector 3-52 4 MegaZoom Concepts and Oscilloscope Operation MegaZoom Concepts 4-3 Run/Stop/Single/Infinite Persistence Operation 4-25 Configuring the Mixed-Signal Oscilloscope 4-32 Using Labels on the Mixed-Signal Oscilloscope 4-42 Page Page Page Page Getting Started MegaZoom Technology Operates with Untriggered Data Page Setting up the Oscilloscope To inspect package contents Page 1-7 Getting Started To inspect package contents s To inspect options and accessories 1-9 Getting Started To inspect options and accessories Table 1-2 Accessories available Page To clean the oscilloscope To adjust the handle To power-on the oscilloscope To adjust the waveform intensity To connect the oscilloscope analog probes To compensate your analog probe To use the digital probes (mixed-signal oscilloscope only) Page Page Page To connect a printer To connect an RS-232 cable To verify basic oscilloscope operation Page P r e s s t h e oscilloscope softkey menus. Using Quick Help Selecting a language for Quick Help when the oscilloscope starts up Selecting a language for Quick Help after you have been operating the oscilloscope Loading an updated language file from floppy disk Page Page Front-Panel Overview Important Oscilloscope Considerations Page Page Page 2-7 54620/40-series Oscilloscope Front Panels 54620/40-series Oscilloscope Front Panels Figure 2-1 2-8 54620/40-series Oscilloscope Front Panels Figure 2-2 2-9 54620/40-series Oscilloscope Front Panels Figure 2-3 Front-Panel Operation Interpreting the display To use analog channels to view a signal To use digital channels to view a signal To display signals automatically using Autoscale To configure the instrument quickly, press the Autoscale key. To apply the default factory configuration To set the instrument to the factory-default configuration, press the To adjust analog channel vertical scaling and position 1 Center the signal on the display using the position knob. To set the vertical expand reference for the analog signal To set analog channel probe attenuation factor To display and rearrange the digital channels To operate the time base controls P r e s s t h e Turn the delay time knob ( ) and notice that its value is displayed in the status line. To start and stop an acquisition To make a single acquisition To use delayed sweep 2Press 3Press the To make cursor measurements 2Press the To make automatic measurements To modify the display grid To print the display Page Triggering the Oscilloscope Selecting Trigger Modes and Conditions To select the Mode and Coupling menu To select a trigger mode: Normal, Auto, Auto Level 1P r e s s t h e 2Press the Page To select trigger Coupling To select Noise Reject and HF Reject To set holdoff Page External Trigger Input 1P r e s s t h e 2P r e s s t h e Trigger Types To use Edge triggering 1P r e s s t h e the Edge trigger menu. 3 Select 1, 2, Ext, or Line as the trigger source. Page To use Pulse Width triggering 1P r e s s t h e display the Pulse Width trigger menu. 2Press the oscilloscopes) to select a channel source for the trigger. 4 Press the qualifier softkey (< > ><) to select the time qualifier. Page To use Pattern triggering 1P r e s s t h e the Pattern trigger menu. Page To use CAN triggering 2P r e s s t h e 3P r e s s t h e 4P r e s s t h e 5P r e s s t h e signal line. To use Duration triggering 4P r e s s t h e pattern. 5 Select a qualifier time set softkey ( set the duration qualifier time. To use I2C triggering 4P r e s s t h e conditions: Page 5 If you have set the oscilloscope to trigger on an EEPROM Data Read condition: Condition Page To use Sequence triggering Page Define the Find: stage 1P r e s s t h e Define the Trigger on: stage Define the optional Reset on: stage Page To use SPI triggering Set up the number of bits in the serial data string and set values for those data bits Resetting all bits in the serial data string to one value. Assign source channels to the clock, data, and frame signals Page Page To use TV triggering 5P r e s s t h e Page To trigger on a specific line of video Page To trigger on all TV line sync pulses To trigger on a specific field of the video signal To trigger on all fields of the video signal To trigger on odd or even fields Page To use USB triggering 2Press the probed. Page The Trigger Out connector Page Page MegaZoom Concepts Deep Memory Oscilloscope Responsiveness Display Update Rate To setup the Analog channels 1P r e s s t h e oscilloscopes) of the front panel to display the channel 1 menu. 2P r e s s t h e 3P r e s s t h e 4P r e s s t h e 5P r e s s t h e 6P r e s s t h e 7P r e s s t h e To setup the Horizontal time base 1P r e s s t h e 2P r e s s t h e 4P r e s s t h e 5 Note the setting of the Time Ref (time reference) softkey. 6 Turn the delay knob ( ) and notice that its value is displayed in the status line. Page Page Page Acquisition Modes P r e s s t h e Page Page Page Display modes P r e s s t h e Page Pan and Zoom To pan and zoom a waveform Run/Stop/Single/Infinite Persistence Operation Acquiring Data Memory Depth/Record Length To run and stop an acquisition To begin an acquisition, press Run/Stop (key is illuminated green when running). To stop an acquisition in process, press Run/Stop (key is illuminated red when stopped). To take a single trace P r e s s t h e To capture a single event 1 Connect a signal to the oscilloscope. 2 Set up the trigger. 3P r e s s t h e To use infinite persistence To use infinite persistence to store multiple repetitive events To clear the waveform display P r e s s t h e Configuring the Mixed-Signal Oscilloscope To display digital channels using Autoscale Interpreting the digital waveform display To display and rearrange the digital channels To turn individual channels on and off To force all channels on or all channels off To change the display size of the digital channels To change the logic threshold for digital channels Using Digital Channels to Probe Circuits Page Page Page Page To turn the label display on or off To assign a predefined label to a channel To define a new label Page To reset the label library to the factory default 1P r e s s t h e 2P r e s s t h e Saving and Recalling Traces and Setups To Autosave traces and setups To save traces and setups to internal memory or to overwrite an existing floppy disk file To save traces and setups to a new file on the floppy disk To recall traces and setups Saving (printing) screen images to floppy disk Recalling the factory default setup Page Making Measurements Capturing Data To use delayed sweep 2Press the 3Press the Page To reduce the random noise on a signal Page 3 Use averaging to reduce noise on the displayed waveform. Page To capture glitches or narrow pulses with peak detect and infinite persistence 2 To find the glitch, press the Acquire key, then, press the Peak Det softkey. 3P r e s s t h e 4 Characterize the glitch with delayed sweep. To use the Roll horizontal mode P r e s s t h e To use the XY horizontal mode Page 6 Move the Y1 and Y2 cursors to the intersection of the signal and the Y axis. 7 Calculate the phase difference using the formula below. Page Math Functions Math Scale and Offset 1P r e s s t h e (units/division) or offset (units) for the selected math function. 2P r e s s t h e change the offset value for your math function. Multiply Subtract Differentiate Page Integrate Page FFT Measurement Page FFT Operation 1P r e s s t h e to display the FFT menu. 2 Press the More FFT softkey to display additional FFT settings. 3 To make cursors measurements, press the softkey to Math. 4 To make other measurements, press the Quick Meas key and set the Page Cursor Measurements To make cursor measurements 2Press the 3P r e s s t h e which the Y cursors will indicate measurements. 4 Select the X and Y softkeys to make a measurement. Page Page Page Automatic Measurements Making automatic measurements Making time measurements automatically Measurement definitions Page Page Making Delay and Phase Measurements P r e s s t h e delay measurement. P r e s s t h e for the phase measurement. Making voltage measurements automatically Page Page Making overshoot and preshoot measurements Page Page Page Utilities To configure Quick Help languages Page To update your instrument to the latest application software To configure a printer 1P r e s s t h e configuration menu. 2Press the 3P r e s s t h e Page To use the floppy disk 3 To delete a file from the floppy disk, press the Delete File softkey. To set up the I/O port to use a controller 1P r e s s t h e GPIB. 2P r e s s t h e 3P r e s s t h e Page To set the clock To set up the screen saver 1P r e s s t h e softkey to display the screen saver menu. 2Press the Page To perform service functions P r e s s t h e menu. P r e s s Page To set other options Page Page 7-3 Agilent 54620-series Performance Characteristics Acquisition: Analog Channels Acquisition: Digital Channels (on 54621D and 54622D only) 7-4 Vertical System: Analog Channels 7-5 Vertical System: Analog Channels (continued) Vertical System: Digital Channels (54621D and 54622D only) 7-6 Horizontal 7-7 Trigger System Page 7-9 Display System Measurement Features Page Page Page 7-13 Agilent 54640-series Performance Characteristics Acquisition: Analog Channels Acquisition: Digital Channels (on 54641D and 54642D only) 7-14 Vertical System: Analog Channels 7-15 Vertical System: Analog Channels (continued) > Vertical System: Digital Channels (54641D and 54642D only) 7-16 Horizontal 7-17 Trigger System Page 7-19 Display System Measurement Features Page Page Page Index Index-1 Index-2 Index-3 Index-4 DECLARATION OF CONFORMITY Product Regulations DECLARATION OF CONFORMITY Product Regulations Safety Notices ! Notices