Mixed-signal oscilloscopes (MSOs)

Mixed signal oscilloscopes are standard oscilloscopes with added digital channel inputs.

Many PicoScopes have corresponding MSO versions which provide up to 16 digital channels in addition to the analog channels.

The digital channels are displayed individually and/or grouped together in a bus display, all time correlated with the analog channels around the same trigger point.

Digital channels

Each digital channel is displayed as a trace which can either be high or low depending on whether the voltage on that channel is above or below a set threshold.

The bus value can be displayed in hex, binary, decimal, or level for DAC testing.

Triggering

The digital channels are displayed around the same trigger point as the analog channels ensuring that the digital channels are time correlated with the analog channels. 

The trigger source can be any of the analog or digital channels.

Advanced digital triggering allows trigger conditions to be specified on multiple digital channels so that a given pattern can be isolated.

Serial protocol decoding

Serial bus decoders are standard with the PicoScope software, and can be applied to the digital channels in the same way as the analog channels.

In this example two serial buses are being decoded, an I2C bus using 2 digital channels and an SPI bus using 3 digital channels.

A 3 bit counter is also displayed.

Using the digital channels for the serial buses leaves the analog channels free to probe other signals on the device.

Timing resolution

Timing resolution is determined by the sample rate of the MSO. A rising or falling edge can only be detected and displayed once the signal has been sampled after crossing the threshold voltage set, and could have occurred at any point after the previous sample point.

Where timing resolution is important then the sample rate of the MSO needs to be considered accordingly.

Acquisition memory depth (Buffer memory) is also a key consideration here as more memory allows a higher sample rate over longer time windows.

To find the PicoScope MSOs, go to the Oscilloscope comparison chart and check the "Mixed signal oscilloscopes" box.