HP54600A oscilloscope

This oscilloscope is an earlier version of the oscilloscope used in the basic laboratory. Reviewing of this oscilloscope will happen during the basic laboratory education. Here we will deal only with the special access modes, the reading of the content of the screen, the FFT module, and with masking necessary for the examination of signal shapes.

Accessing the oscilloscope to remote-fed symmetric signal cables

It causes difficulties to access oscilloscopes to remote-fed symmetric interface cables, because oscilloscopes have asymmetric inputs. Principally we can ground down one of the branches of the symmetric pair of cables, but this grounding can spoil the perplexity protection of the interface in many cases, and thus we will see the perplexity power instead of the signal. We can short-circuit the remote-fed circuit with the grounding, stopping the operation of the terminal tool connected to the interface.
Examining a symmetric interface cable we can connect the oscilloscope in two ways:

• using two vertical inputs in differential mode
• - using a symmetry-making measuring transformator (in the laboratory we apply this solution in most of the cases). Symmetry-making transformator measuring heads have direct current scaling, and 0 or 20 dB of attenuation! Circuit diagram of the measuring heads can be seen on the following figure:

  

  There is a separated measuring head for measures of voice frequency (0.2...20 kHz) and higher frequency (0.2...2 MHz)!!! There is a measuring head, which is connected to the T2-R2 points of the RJ-11 connector (4-wire transmission).

Capturing the screen of HP54600A

• Open the MS Word report file, and then click on the table to the "Oscilloscope HP54600? icon. Agilent 54600 icon will indicate the connection between the oscilloscope and the computer.
• If we click to the camera of the Agilent 54600 icon, then the figure of the oscilloscope will be copied into the report file, to the place marked by the cursor.
• We can fix the copied figure with the right mouse button/format picture/layout/in line with text command in the report.

Displaying of quasi-periodic, non-periodic signals:

We record one part of the signal in the memory of the oscilloscope. Steps of this process:

• Trigger/Mode/Single
• Vertical/Volts/Div, Horizontal/Time/Div
• Trigger/Source, Trigger/Level
• Storage/Run
• Measure/Cursors

Displaying of spectrum of examined signal. Usage of FFT module:

We should use for displaying of spectrum of the examined signal the mathematical operation-making module of the oscilloscope.
Steps of this procedure:

• Connect the tested signal to channel 1 on the oscilloscope.
• Trigger/Mode/Single
• Vertical/1/Volts/Div, Horizontal/Time/Div
  (We have verify, whether in the channel used for the measurement is overrun, or not!)
• Trigger/Source=1, Trigger/Level
• Vertical/1/Off - switching off the displaying of signal's time function.
• Vertical/+/- - activation of mathematical operation module of the oscilloscope
  _{There are two mathematical operation modules built into the oscilloscope (Function 1, Function 2), which can be switched on and off separately.. FFT can be generated only with the module Function 2!!}
• Switching on the Function 2, we must set in the menu of the operation module:
  • Operand: 1 - the channel, where we connected the tested signal.
  • Operation: FFT
  • Sampling frequency: It can be set not in the menu, but, with the Vertical/Time/Div switch. When switching over the switch, value of the sampling frequency will appear for a short time on the screen. Executing the setting we must take care of keeping the sampling theorem!
  • Units/div, Ref Levl - vertical picture size and position. Values can be set by turning the button ordered to the Measure button group.
  • FFT menu:
    • Cent Freq, Freq Span - set of the horizontal position, and size of picture of the spectrum. Values can be set by turning the button ordered to the Measure button group.
    • Window: Hanning window is recommended.
• Storage/Run - start of the capturing, displaying the registrated data
• Measure/Cursors - evaluation of registrated data, measuring

Loading masks used for examining the signal shapes

We can activate masks used for examining the signal shapes with the SEQUENCE MENU menu element, which can be found in the menu point under the SETUP button. After activating this menu element, the latest used mask will be drawn to the screen. Masks stored in the memory of the instrument can be identified with a serial number. Evaluation can be executed by turning the button besides the SETUP button. Mask can be switched off the the help of the STOP SEQUENCING menu element.