A Digital signal is a time- and value-discrete signal that transmits information in the form of clearly defined states. Unlike analog signals, which can take on continuous values, a digital signal switches between fixed levels and typically represents information as binary states.
In practice, digital signals are often described by two signal states:
- Low (0)
- High (1)
These states are typically represented by different voltage levels. Depending on the technology used, the levels can range, for example, from 0 V to 5 V, 24 V, or other voltage ranges.
In measurement and automation technology, digital signals usually take the form of square-wave signals or near-square-wave signals. The information they contain can be encoded in various ways:
- About the current signal level (high or low)
- About the duration of a pulse
- About the time intervals between signal edges
- About the Frequency of a Periodic Signal
- About Pulse Sequences or Counting Pulses
Digital signals are frequently used in modern measurement and data acquisition systems to record switching states, meter readings, rotational speeds, or position information. They enable robust and interference-free transmission of information and are easy to process and analyze.
Typical sources of digital signals:
- Proximity Switch
- Limit Switch
- Light Barriers
- Incremental encoder
- Rotational Speed and Frequency Sensors
- PLCs
- Relay and Switching Contacts
Applications in measurement and testing technology:
- Recording of Switching States
- Counting Pulses and Events
- Rotational Speed and Frequency Measurements
- Position and Displacement Measurement
- Trigger and Synchronization Signals
- Machine and Equipment Monitoring
Advantages of digital signals:
- High resistance to interference
- Unambiguous Signal States
- Easy Further Processing
- Reliable transmission over long distances
- Ideal for automation and monitoring tasks
Digital signals form a central foundation of modern measurement, testing, and automation systems and enable the reliable acquisition and processing of states, events, and process information.