Moku:Go Waveform Generator User Manual
Moku:Go's Waveform Generator is designed to generate common signals with high accuracy and configurability across two independent output channels. The outputs are precisely adjustable for frequency, phase, and amplitude. Furthermore, the outputs can be modulated with various internally generated or external signals, and feature flexible, programmable triggers.
Version: V21-0323
Website: www.liquidinstruments.com
User Interface
The user interface provides controls for configuring the waveform generator. Key elements are identified by numbers in diagrams:
| ID | Description | ID | Description |
|---|---|---|---|
| 1 | Main menu | 7 | Configure displayed parameter (Out 1) |
| 2 | Configure frequency / period | 8 | Configure displayed parameter (Out 2) |
| 3 | Configure waveform offset | 9 | Configure ramp symmetry |
| 4 | Enable / disable output | 10 | Switch between frequency and period |
| 5 | Waveform shape | 11 | Switch between frequency and period |
| 6 | Configure modulation |
The main menu is accessed by pressing the ☰ icon on the top-left corner.
Sync phase and copy settings between channels can be accessed via a right-click (secondary click) menu on the main user interface. Settings on one output can be instantly applied to the other output using "copy setting". The phase between two channels can be aligned using "sync phase".
Main Menu
The main menu provides the following options:
| Options | Shortcuts | Description |
|---|---|---|
Save/recall settings:
|
Ctrl+S Ctrl+O |
Save the current instrument settings. Load last saved instrument settings. Show the current instrument settings. |
| Reset instrument | Ctrl+R | Reset the instrument to its default state. |
| Power supply | Access power supply control window.* | |
| File manager | Open file manager tool. | |
| File converter | Open file converter tool. | |
Help
|
Ctrl+H F1 |
Access Liquid Instruments website. Show Moku:Go app shortcuts list. Access instrument manual. Report bug to Liquid Instruments. Show app version, check update, or license information. |
* Power supply is available on Moku:Go M1 and M2 models. Detailed information about power supply can be found in the Moku:Go power supply manual.
Output Configuration
Enable / Disable Outputs
A visual indicator shows the state of the output channel: a grey circle indicates the output channel is disabled (click to enable), and a green circle indicates the output channel is enabled (click to disable).
Note on Impedance
Moku:Go's outputs have an impedance of 200 Ω. Voltages supplied to a 50 Ω load will be reduced and are not recommended.
Waveform Types
Each channel can be set to generate one of five predefined waveforms: Sine, Square, Ramp, Pulse, and DC.
Sine, Square, and Ramp waveforms can be configured for Frequency, Amplitude, Offset, and Phase.
Waveform Details
Sine Wave
The Sine wave is the simplest dynamic signal, featuring extremely low harmonic distortion and approximating a pure single frequency. It can be modulated by all available modulation types and serves as the basis for the "Internal" modulation source.
| ID | Description | ID | Description |
|---|---|---|---|
| 1 | Amplitude (High Level) | 3 | Offset (Low Level) |
| 2 | Signal Frequency (Period) | 4 | Phase |
Parameter settings can be changed by clicking the parameter pill or bar. The parameter bar may display different representations of parameters, shown in brackets.
Square Wave
The Square wave is a low-jitter waveform with a variable duty cycle and high slew rates, enabled by the Moku's high analog bandwidth for sharp rise and fall times. For applications requiring slew-rate limits or variable duty cycle, refer to the Pulse Wave.
| ID | Description | ID | Description |
|---|---|---|---|
| 1 | Amplitude (High Level) | 4 | Phase |
| 2 | Signal Frequency (Period) | 5 | Duty Cycle* |
| 3 | Offset (Low Level) |
Parameter settings can be changed by clicking the parameter pill or bar. The parameter bar may display different representations of parameters, shown in brackets.
* Above 2.5 MHz, the duty cycle range is limited between 32% to 68%.
Ramp Wave
The Ramp wave consists of linear ramps from a low level to a high level and back. Symmetry refers to the ratio between the time spent on the rising edge and the overall period. For configurable dwell times at high or low levels with common rise and fall times, the Pulse Wave with large edge times can be used.
| ID | Description | ID | Description |
|---|---|---|---|
| 1 | Amplitude (High Level) | 4 | Phase |
| 2 | Signal Frequency (Period) | 5 | Symmetry |
| 3 | Offset (Low Level) |
Parameter settings can be changed by clicking the parameter pill or bar. The parameter bar may display different representations of parameters, shown in brackets.
Pulse Wave
The Pulse wave is similar to the Square wave but features configurable edge times (rise and fall time). The trade-off is slightly worse edge jitter behavior at high frequencies compared to the Square wave.
| ID | Description | ID | Description |
|---|---|---|---|
| 1 | Amplitude (High Level) | 4 | Phase |
| 2 | Signal Frequency (Period) | 5 | Pulse Width |
| 3 | Offset (Low Level) | 6 | Edge time |
Parameter settings can be changed by clicking the parameter pill or bar. The parameter bar may display different representations of parameters, shown in brackets.
DC Wave
Provides a high-precision, fixed reference voltage at the output.
| ID | Description |
|---|---|
| 1 | DC level |
Parameter settings can be changed by clicking the parameter pill or bar to change the DC level.
Modulation Types
Moku's Waveform Generator supports various modulations, available on all waveforms except DC. Ramp waveforms can only be amplitude modulated, while other waveforms support Amplitude, Frequency, or Phase modulation, and can be continuous or triggered in burst or sweep modes.
Amplitude Modulation
Amplitude modulation changes the amplitude of the generated signal proportionally to the modulation input. The "modulation depth" defines this proportion.
| ID | Parameter | Description |
|---|---|---|
| 1 | Frequency | Only for "Internal" modulation; the frequency of the sine wave used for modulation. |
| 2 | AM Depth | Fractional depth of modulation. 100% depth reduces the signal amplitude to zero for a full-range negative modulation signal. |
| 3 | Modulation Source | The modulation source can be a Moku input, the other Moku output, or an internally-generated sine wave. |
Frequency Modulation
Frequency modulation changes the frequency of the generated signal proportionally to the modulation input. The "modulation depth" defines this change.
| ID | Parameter | Description |
|---|---|---|
| 1 | Frequency | Only for "Internal" modulation; the frequency of the sine wave used for modulation. |
| 2 | FM Deviation | Full-range frequency deviation. A full-range input signal will vary the output frequency by this amount. |
| 3 | Modulation Source | The modulation source can be a Moku input, the other Moku output, or an internally-generated sine wave. |
Phase Modulation
Phase modulation changes the phase of the generated signal proportionally to the modulation input. The "modulation depth" defines this change.
| ID | Parameter | Description |
|---|---|---|
| 1 | Frequency | Only for "Internal" modulation; the frequency of the sine wave used for modulation. |
| 2 | Depth | Full-range phase deviation. A full-range input signal will vary the output phase by this amount. |
| 3 | Modulation Source | The modulation source can be a Moku input, the other Moku output, or an internally-generated sine wave. |
Triggered Modulation Modes
Sine, Square, and Pulse waves can be triggered from an external source. The behavior upon receipt of the trigger signal varies according to the trigger mode.
Burst Mode
In burst mode, a trigger event causes the output to begin generating its configured waveform. Burst mode requires specifying a sub-mode for generation timing.
| ID | Parameter | Description |
|---|---|---|
| 1 | Cycle count | N - Cycle mode only. The number of cycles to generate before re-arming. |
| 2 | Burst period | Total period of time for the burst. |
| 3 | Trigger source | One of: Internal (automatic rate), External (rear-panel trigger input), Input (associated input channel), Output (opposite output channel). |
| 4 | Mode | One of: Gated (generate while trigger is high), Start (generate indefinitely after trigger), N Cycle (generate specified cycles then re-arm). |
Sweep Mode
Sweep mode provides frequency modulation with a sawtooth that starts on the trigger event. Waveform generation begins at the Start frequency and sweeps to the End frequency over a specified duration.
Sweep mode has three configurable parameters:
- Start Frequency: Initial frequency of the output waveform upon trigger detection. The waveform's frequency is entirely defined by the sweep parameters.
- End Frequency: Final frequency of the output waveform after the trigger.
- Duration: The time taken to sweep from Start to End frequency. After completion, the sweep circuit re-arms for a new trigger input.
The Trigger Source can be Internal, External, Input, or Output, similar to Burst Mode.
Power Supply
The Moku:Go Power Supply is available on M1 (2-channel) and M2 (4-channel) models. The control window is accessible via the main menu.
The power supply operates in two modes: Constant Voltage (CV) or Constant Current (CC). Users set current and voltage limits. The supply operates at the set current or voltage, whichever limit is reached first. Voltage-limited operation is CV mode; current-limited operation is CC mode.
| ID | Function | Description |
|---|---|---|
| 1 | Channel name | Identifies the power supply being controlled. |
| 2 | Channel range | Indicates the voltage/current range of the channel. |
| 3 | Set value | Click blue numbers to set voltage and current limits. |
| 4 | Readback numbers | Displays actual voltage and current supplied to the load. |
| 5 | Mode indicator | Indicates if the power supply is in CV (green) or CC (red) mode. |
| 6 | On/Off Toggle | Click to turn the power supply on and off. |
Instrument Reference
Waveform Types
The Moku:Lab's waveform generator can produce five different signals with optional modulation:
- Sine Wave: Simplest signal, low harmonic distortion, approximates pure frequency. Can be modulated by all types and serves as the "Internal" modulation source.
- Square Wave: Low-jitter, variable duty cycle, high slew rates due to high analog bandwidth. For slew-rate limits or variable duty cycle, see Pulse Wave.
- Ramp Wave: Linear ramps from low to high and back. Symmetry is the ratio of rising edge time to the overall period. Pulse Wave with large edge times can be used for configurable dwell times.
- Pulse Wave: Similar to Square wave but with configurable edge times. Trade-off is slightly worse edge jitter behavior at high frequencies.
- DC: Provides a high-precision, fixed reference voltage.
Waveform Parameters
- Amplitude: Specified as Peak-to-Peak (high level minus low level). Can be toggled between Peak-to-Peak and High/Low level specification. Applicable to Sine, Square, Ramp, Pulse.
- Frequency: Specified in Hertz or period in seconds. Applicable to Sine, Square, Ramp, Pulse.
- Offset: Average value of the waveform over time. Alternative representation is Low Level. Applicable to Sine, Square, Ramp, Pulse.
- Phase: Defines waveform phase relative to Moku's internal reference. Can be synced to the other output channel. Applicable to Sine, Square, Ramp, Pulse.
- Symmetry: Ratio (percent) of rising edge time to the overall period. Ramp wave becomes sawtooth at 0% and 100% symmetry. Applicable to Ramp.
- Pulse Width: Positive width of the pulse. Edge Time is split between Pulse Width and the rest of the cycle, preserving duty cycle. Applicable to Pulse.
- Edge Time: Time taken for transition from low to high level. Limits slew rate. Split equally between high and low time, preserving duty cycle. Applicable to Pulse.
- Duty Cycle: Percentage of the period the signal is active. Similar to pulse width, but edge time is not factored in due to fast rise/fall times. Applicable to Square.
- DC Level: Fixed voltage to output. Applicable to DC.
Note: Minimum rise and fall time is 2ns, meaning 0% or 100% symmetry may not be perfectly achievable.
Modulation Types and Trigger Modes
Modulation Sources
Each modulation type can be driven by one of three sources:
- Internal: Driven by an internally-generated sine wave of configurable frequency and full-range amplitude.
- Input: Driven by the corresponding analog input (e.g., Output 1 by Input 1). Depth is specified per volt on the input.
- Output: Driven by the opposite analog output (e.g., Output 1 by Output 2). Allows for doubly-modulating signals.
Trigger Sources
Burst and Sweep modes depend on trigger event detection. Three possible sources exist:
- Internal: Trigger event generated automatically at a specified rate.
- External: Rising edge on the back-panel External Trigger Input. Refer to Moku:Lab Technical Specifications for details.
- Input: Rising edge on the corresponding Analog input past a specified voltage (Output 1 from Input 1, Output 2 from Input 2).
- Output: Rising edge on the opposite Analog output past a specified voltage.
Modulation Details
Amplitude Modulation
Changes signal amplitude proportionally to the modulation input, defined by modulation depth.
Frequency Modulation
Changes signal frequency proportionally to the modulation input, defined by modulation depth (Hertz or Hertz per Volt).
Phase Modulation
Changes signal phase proportionally to the modulation input, defined by modulation depth (Degrees or Degrees per Volt).
Burst Mode
Trigger event initiates waveform generation. Sub-modes define termination:
- N-Cycle: Stops after specified cycles, then re-arms.
- Gated: Continues generation while the trigger signal is high (level-triggered).
- Start: Begins generation on trigger and continues indefinitely.
Sweep Mode
Frequency modulation using a sawtooth that starts on trigger. Generation begins at Start Frequency and sweeps to End Frequency over a specified Duration.
- Start Frequency: Initial frequency upon trigger.
- End Frequency: Final frequency after the trigger.
- Duration: Time taken for the sweep.
The waveform's frequency parameters are entirely defined by the sweep.
General Information
Ensure Moku:Go is fully updated. For the latest information, visit www.liquidinstruments.com.
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