The model number on the Tektronix MDO3104 oscilloscope denotes that it is a 3000-Series Mixed-Domain Oscilloscope. The mixed domain moniker means it is capable of displaying a waveform simultaneously in the time domain and in the frequency domain. The time domain is more familiar, the way we envision a sine wave when amplitude is plotted in Cartesian co-ordinates against the Y-axis, usually displayed in volts, or multiples or decimal parts thereof, such as millivolts or microvolts. Time in seconds in milliseconds is plotted against the X-axis.
Returning to the oscilloscope model number, 1 denotes that there is one AFG output channel. Four denotes that there are four analog channels.
The MDO models should not be confused with the MSO models. These are mixed-signal instruments, which can display two separate signals, as when one channel is connected to an analog or digital output. This is convenient for troubleshooting to see if intermittent signal anomalies are caused by power-supply pauses.
Key features of MDO3000 Series Oscilloscopes include that they are all mixed-domain instruments. In addition to the FFT mode described above, they have a built-in spectrum analyzer, arbitrary function generator with 13 available waveforms, logic analyzer, protocol analyzer, digital voltmeter and frequency counter. Additionally:
Dedicated RF input channel for frequency-domain measurements
Four or two analog channels for time-domain measurement
Models available with bandwidths from 100 MHz to 1 GHz
Sample rates of 2.5 GS/sec on all analog channels (5 GS/sec on one or two channels for the MDO3104 and MDO3102)
10 M points of record length on all channels
Maximum waveform capture rate: >280,000 waveforms/sec with Fastacq, 50,000 waveforms/sec with normal operation
Advanced triggering and analysis: I2C, SPI, USB 2.0, CAN, LIN, FlexRay, RS-232, RS-422, RS-485, UART, I2S, Left Justified, Right Justified, TDM, MIL-STD-1553 with appropriate module and Parallel Transmission
Power Analysis and Limit and Mask Testing application modules (optional)
Digital Voltmeter free with registration
Optional accessories include:
Selection of available probes
An oscilloscope probe cannot be used until it has been compensated to match the signal path (individual analog channel) with which it is to be used. The compensation process is necessary for all non-Tektronix oscilloscope models. It essentially involves sensing a square wave, available from terminals on the front panel, observing it on the oscilloscope screen and adjusting a screw on the probe body until the square wave has nice square corners. This takes place for each probe-channel combination and then the probes are numbered or color-coded so that you will always know which probe is to be used for each channel.
The Tektronix MDO3000 Series probe compensation process is automated and versatile. To this end, the system has a memory and all probes can be compensated for all channels so you never have to worry about color-coding or getting the right combination. Here’s how it’s done:
Plug a TPP 1000 probe into the desired channel and connect the probe with a hook tip to the square-wave terminals on the front panel, observing polarity. Be sure the front panel button associated with the channel is On. Notice that in the lower menu the oscilloscope has automatically set the probe termination values.
Press More repeatedly to select Probe Setup from the resulting pop-up menu. Notice the compensation process starts as Default. Press Compensate Probe and follow the instructions on the display. Each compensation generates values for the specific probe-channel combination. Don’t forget to number or color-code each probe. If you want to compensate a probe for an additional channel, you must run a new set of compensation steps. Each channel can store values for 10 individual probes. If you try to compensate an 11th probe on a channel, the oscilloscope will delete the values for the least recently used probe and add the values for the new probe. A factory calibration will delete all stored compensation values.
A probe-related source of distortion not involving probe compensation, is the length of the ground-return lead, which introduces unwanted inductance into the circuit.
Obviously, you cannot set the oscilloscope on top of a circuit board under investigation. That being said, the ground return lead should be as short as possible.
Two of the most-used buttons on the front panel of a modern digital oscilloscope are Default Setup and Autoset. Default Setup is indispensable when, after power-cycling briefly or shutting down for an extended interval and turning it back on, some of the previous settings persist. They can be inconvenient, especially for new users who will have difficulty finding the location of the setting or when accessing an unfamiliar waveform such as Haversine. Or it can be troublesome if the oscilloscope is in a bandwidth-limited mode. The simple solution is to press Default Setup at the bottom of the front panel.
Users of old analog oscilloscopes had a similar problem. When accessing a new waveform, frequently it would appear as a disorganized jumble of curves with no sign of triggering. The user would have to adjust amplitude, frequency and phase and get them all to coincide before getting a meaningful waveform. Today, we just press Autoset at the top. A clear, triggered waveform is displayed and subsequent waveforms with the same parameters are correctly shown.
The instrument’s capability can be extended by means of optional applications. Two application modules can be installed simultaneously They can be inserted into the slots having a window at the upper right of the front panel. Behind the slot that is visible, there is a hidden slot. It can be used by installing a module with the label facing to the back.
Two licenses associated with certain modules can be installed simultaneously. This allows the user to move the module between instruments or to move the license from a module to an oscilloscope, so it can be stored separately. Also, two or more applications can be used simultaneously in the oscilloscope. The procedure to transfer a license from module to oscilloscope or from oscilloscope to module is:
1. Power down the oscilloscope. Insert the application module into the instrument. Turn the power in the oscilloscope back On.
2. Press Utility at the bottom of the front panel. Press Utility Page on the lower menu and Options in the lower menu and press License Type in the side menu so that Modules is selected. Press the button next to the license that is to be transferred.
3. Turn Off the power and remove the physical application module. Refer to the installation manual accompanying the application module for instructions on installing the module.
4. If a license is transferred from a module to an oscilloscope, it will not work in another oscilloscope unless the license is transferred back from the oscilloscope to the module.
The user manual that comes with the oscilloscope contains instructions for signal path compensation, required for ambient temperature changes, and for firmware upgrades., which are simpler than you may think. They are a possible solution if the oscilloscope freezes on the opening page. Firmware upgrades are available at the Tektronix website.