- What is a Function Generator?
- Key Functions
- What Is It Used For?
- Main Interface
- How to Use
- Output Channels
- Function Generator Settings
- Waveform Settings
- Additional Controls
- Summary of Operation
What is a Function Generator?
A function generator is an instrument that creates electrical waveforms of different shapes, frequencies, and amplitudes. By configuring parameters like frequency, amplitude, offset, and waveform type, you can inject test signals into circuits for analysis or troubleshooting.
Key Functions
- Waveform Generation: Outputs common shapes such as sine, square, triangle, sawtooth, DC, and PWM.
- Adjustable Parameters: Control frequency, amplitude, DC offset, phase, and duty cycle.
- Advanced Modes: Sweep and burst modes allow you to scan through a range of frequencies or generate pulsed bursts of signals.
- Trigger Options: Internal or external triggers can be used to synchronize signal generation with other devices or events.
What Is It Used For?
- Circuit Testing: Inject known signals into a circuit to observe its response and identify faults.
- Filter and Amplifier Characterization: Sweep across frequencies to evaluate how filters or amplifiers behave over a range.
- Educational Demonstrations: Teach signal properties, wave shaping, and system responses in lab settings.
- Microcontroller or Sensor Simulation: Emulate sensor outputs or clock signals for prototyping and debugging embedded systems.
Main Interface
The main interface for the function generator in the Red Pitaya environment is typically located on the right side of the Oscilloscope & Signal Generator application. It is divided into logical sections, each controlling different aspects of the output signal.
How to Use
- Select a Channel: Click OUT1 or OUT2 to open its settings panel.
- Enable Output: Toggle ON to start sending the configured signal to the output connector.
- Preview Signal: Check or uncheck SHOW to see a rough preview of the waveform within the interface.
Output Channels
Each Red Pitaya board supports up to two independent function generator channels: OUT1 and OUT2.
Key Elements:
- ON: Toggles the channel output on or off.
- SHOW: Displays a software preview of the waveform (not necessarily phase-aligned with the physical output).
- Channel Selection: Clicking on OUT1 or OUT2 (rather than the gear icon) highlights that channel for editing.
Function Generator Settings
Waveform Settings
These settings determine the shape and core characteristics of the signal produced on the selected channel.
Key Parameters:
- Type: Choose from predefined waveforms (SINE, SQUARE, TRIANGLE, SAWU, SAWD, DC, DC_NEG, PWM) or custom waveforms loaded via the ARB Manager.
- Frequency (Hz): The repetition rate of the waveform.
- Amplitude (V): The one-way amplitude (relative to ground). For example, an amplitude of 1 V on a sine wave spans -1 V to +1 V if offset is zero.
- Offset (V): Adds a DC shift to the waveform (e.g., shifting a sine wave up or down).
- Phase (deg): Adjusts the initial phase angle of the waveform.
- Duty Cycle (%): Defines the “on” time versus total cycle time for PWM or square waves.
- Rise Time / Fall Time (µs): Controls how quickly the signal transitions from low to high and vice versa, affecting edge sharpness.
How to Use
- Select Waveform Type: Click the Type dropdown and choose the desired shape (e.g., SINE, SQUARE, etc.).
- Set Frequency & Amplitude: Enter numeric values or use the up/down arrows to dial in your signal parameters.
- Offset & Phase: If your application requires a specific DC bias or phase alignment, set these fields accordingly.
- PWM / Square Wave Settings: For pulse-type signals, adjust the Duty Cycle and Rise/Fall Time to shape the edges and on/off ratios.
Additional Controls
Advanced signal features allow you to configure sweeps, bursts, and triggering options for more specialized testing scenarios.
Key Features:
- SWEEP MODE: Varies the frequency (or other parameters) from a start to an end value over a set duration. Ideal for analyzing circuit response over a range of frequencies.
- BURST MODE: Outputs a specific number of cycles or pulses in a single burst, then stops until re-triggered.
- Trigger:
- Internal: Uses the generator’s internal clock to trigger the signal.
- External: Waits for an external signal or event to initiate waveform output.
- TRIG GEN: Manually triggers the function generator, useful when Burst or certain Sweep modes are enabled.
How to Use
- Configure SWEEP: Click SWEEP MODE, set start/stop frequencies and sweep duration or type (linear/logarithmic).
- Set BURST Parameters: Specify the number of cycles, burst period, or other relevant details in BURST MODE.
- Choose Trigger Source: Switch between Internal or External trigger depending on your test setup.
- Manual Trigger: Use TRIG GEN if you want to force the generator to start immediately, bypassing waiting conditions.
Summary of Operation
- Select Output Channel: Click OUT1 or OUT2, toggle ON, and choose SHOW if you need a preview.
- Define Waveform Parameters: Set Type, Frequency, Amplitude, Offset, and any additional properties like Phase or Duty Cycle.
- Use Advanced Features: Enable SWEEP or BURST modes for dynamic or pulsed signal generation, and configure triggers as needed.
- Output & Observe: Once you’ve set all parameters, the function generator will continuously output your configured waveform until turned off or reconfigured.