Digital Signal Processing (DSP)

• Digital Signal Processing (DSP) involves using digital processors for digital conditioning of signals.
• Signal conditioning steps: sensing, variable conversion, signal conditioning, transmission, and recording.
• Signals convert from analog to digital format after signal conditioning.
• After the signal is transmitted to the controller, it is recorded/stored.
• Before being sent to the actuator, the signal converts back to analog for smooth processes and interaction with the actuator.

Major Signal Conditioning Functions

• Signals are filtered to remove unwanted frequencies.
• AC power lines transmit electricity at 50 to 60 cycles per second.
• Isolation transmits the signal through a non-physical connection.
• Magnetic and optical isolation depend on the form the signal is converted to, to determine the mode of transmission.
• Magnetic isolation converts signals into a magnetic signal for transmission over a magnetic field.
• Amplification improves the signal strength.
• PC data acquisition hardware converts analog signals to digital signals.
• Transducers preserve the original information of a signal before conversion.

Minor Signal Conditioning Functions

• Transducer excitation is used for passive sensors that rely on their measurand for power, not an external source.
• Linearization makes the sensor output and the measurand have a linear relationship using algorithms and math.
• Cold junction compensation removes small voltage errors from the presence of the terminal block at the cold junction.
• Thermocouples are temperature sensors that output voltages and use temperature as the measurand.
• Multiplexing transmits different signals from different sensors through the same physical connection.
  • Benefit: Reduces cost.
  • Drawbacks: Slows down transmission and complicates processes.