Handheld Oscilloscope Measures Sinusoidal Signals

In this setup, Oscium’s iMSO-104 oscilloscope is measuring the output of a signal generator (sig gen) and using an iPad2 for displaying the waveform. The measurement uses iMSO-104’s single analog input channel. The handheld oscilloscope’s probe is connected directly to the output of the sig gen as a high impedance load. This equipment setup is commonly used for calibrating the measurement instrument against a known reference signal. For this photograph, the sig gen is configured for a 200 Hz sine wave.

Signal Source and Measurement Instrument

Oscilloscopes plot voltage as a function as time. Like traditional “big-box” instruments, Oscium’s oscilloscope has variable resolution and precision parameters that users can tailor to each application. Expanding or decreasing the time scale, the horizontal axis, has a proportional effect on the measurement resolution and precision. To capture a few cycles of a periodic function on the oscilloscope’s screen, the time scale must be expanded or decreased at the cost of precision at each individual point. This tradeoff is the equivalent of “zooming in” to see the waveform with maximum precision or “zooming out” to view the periodic nature of the signal over time.

Using a Sig Gen as a Reference Source for Equipment Compensation

As previously mentioned, signal generators are typically used as a “source” to create the stimulus signal(s) for a circuit, but for troubleshooting and debugging, sig gens provide the necessary reference signals for instrument ccompensation. In fact, the first step into investigating a circuit’s operation is compensating the measurement instruments against a reference signal to account for losses and other characteristics of the test setup. Configure the sig gen to produce an output that is close to the expected output characteristics of the device under test, and then set the oscilloscope’s setup parameters appropriate to the measurement. The iMSO App allows users to save multiple instrument states for recall while testing. This time saving feature allows a user to configure iMSO-104 for a specific measurement using a reference signal, and then recall those saved instrument parameters when testing the actual circuit.