LIQUID INSTRUMENTS Moku:Go Waveform Generator User Manual
- June 5, 2024
- Liquid instruments
Table of Contents
LIQUID INSTRUMENTS Moku:Go Waveform Generator
User Interface
- Main menu
- Configure displayed parameter (Out 1)
- Configure frequency / period
- Configure displayed parameter (Out 2)
- Configure waveform offset
- Configure ramp symmetry
- Enable / disable output
- Switch between frequency and period
- Waveform shape
- Switch between frequency and period
- Configure modulation
Sync phase with copy settings between channels can be accessed by right click (secondary click) menu on the main user interface. The settings on one output can be instantly applied to the other output with copy setting. And the phase between two channels can be aligned with sync phase.
Main Menu
The main menu can be accessed by pressing the icon on the top-left corner.
This menu provides the following options:
| Options | Shortcuts | Description |
|---|---|---|
| Save/recall settings: | ||
| · Save instrument state | Ctrl+S | Save the current instrument |
settings.
· Load instrument state| Ctrl+O| Load last saved instrument
settings.
· Show current sate| | Show the current instrument settings.
Reset instrument| Ctrl+R| Reset the instrument to itss default state.
Power supply| | Access power supply control window.*
File manager| | Open file manager tool.
File converter| | Open file converter tool.
Help| |
· Liquid Instruments website| | Access Liquid Instruments
website.
· Shortcuts list| Ctrl+H| Show Moku:Go app shortcuts list.
· Manual| F1| Access instrument manual.
· Report an issue| | Report bug to Liquid Instruments.
· About| | 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 Moku:Go power supply manual.
Output Configuration
Enable / Disable Outputs
- shows the output channel is disabled, click to enable
- shows the output channel is enabled, click to disable
Note on impedance
Moku:Go’s outputs have an impedance of 200 Ω. As such, voltages supplied to a
50 Ω load will be reduced and not recommended.
Waveform types
Each channel can be set to generate one of five predefined
waveforms.
Each of Sine, Square and Ramp can be configured for Frequency, Amplitude, Offset and Phase.
Sine Wave
| ID | Description | ID | Description |
|---|---|---|---|
| 1 | Amplitude (High Level) | 3 | Offset (Low Level) |
| 2 | Signal Frequency (Period) | 4 | Phase |
Click Parameter Settings pill or bar to change. Parameter bar can show different representations of many parameters; these alternative representations are shown in brackets.
Square Wave
| ID | Description | ID | Description |
|---|---|---|---|
| 1 | Amplitude (High Level) | 4 | Phase |
| 2 | Signal Frequency (Period) | 5 | Duty Cycle* |
| 3 | Offset (Low Level) |
Click Parameter Settings pill or bar to change. Parameter bar can show different representations of many parameters; these alternative representations are shown in brackets.
Ramp Wave
| ID | Description | ID | Description |
|---|---|---|---|
| 1 | Amplitude (High Level) | 4 | Phase |
| 2 | Signal Frequency (Period) | 5 | Symmetry |
| 3 | Offset (Low Level) |
Click Parameter Settings pill or bar to change. Parameter bar can show different representations of many parameters; these alternative representations are shown in brackets.
Pulse Wave
Click Parameter Settings pill or bar to change. Parameter bar can show different representations of many parameters; these alternative representations are shown in brackets.
DC 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 |
Click Parameter Settings pill or bar to change the DC level.
Modulation types
Moku’s Waveform Generator supports a variety of modulations. Modulation is
available on all waveforms except DC. Ramp waveforms can only be amplitude
modulated; but all other waveforms can be Amplitude, Frequency or Phase
modulated and can be continuous or triggered in burst or sweep modes.
Amplitude modulation
| ID | Parameter | Description |
|---|---|---|
| 1 | Frequency | Only for “Internal” modulation; the frequency of the sine |
wave being used for modulation.
2| AM Depth| Fractional depth of modulation. 100% depth will reduce 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 a “internal”, an internally-generated sinewave.
Frequency modulation
| ID | Parameter | Description |
|---|---|---|
| 1 | Frequency | Only for “Internal” modulation; the frequency of the sine |
wave being 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 a “internal”, an internally-generated sinewave.
Phase modulation
| ID | Parameter | Description |
|---|---|---|
| 1 | Frequency | Only for “Internal” modulation; the frequency of the sine |
wave being 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 a “internal”, an internally-generated sinewave.
Triggered modulation modes
Sine, Square and Pulse waves can be triggered from an external source. The
behaviour upon receipt of the trigger signal varies according to the trigger
mode.
Burst
| 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: Trigger automatically at the defined rate
External: Trigger event on from rear-panel external trigger input Input: Trigger from associated input channel, at given voltage Output: Trigger from opposite output channel, at given voltage
4| Mode| One of:
Gated: Continue to generate the output signal while ever the trigger event is asserted (level-triggered)
Start: Begin generation of the waveform on trigger, continue indefinitely.
N Cycle: Upon receipt of trigger signal, generate this many cycles of the waveform then re-arm.
Sweep
Sweep modulation acts like frequency modulation with a sawtooth, where the sawtooth starts on the trigger event.
| ID | Parameter | Description |
|---|---|---|
| 1 | Start Frequency | Waveform frequency at the trigger event (sweep |
start)
2| End Frequency| Waveform frequency at the sweep end
3| Trigger Source| One of:
Internal: Trigger automatically at the defined rate
External: Trigger event on from rear-panel external trigger input Input: Trigger from associated input channel, at given voltage Output: Trigger from opposite output channel, at given voltage
4| Sweep Time| Time between sweep start and end
Power Supply
Moku:Go Power supply is available on M1 and M2 models. M1 features a 2-channel
power supply, while M2 features a 4-channel power supply. The power supply
control window can be accessed in all instruments under the main menu.The
power supply operates in two modes: constant voltage (CV) or constant current
(CC) mode. For each channel, the user can set a current and voltage limit for
the output. Once a load is connected, the power supply operates either at the
set current or set voltage, whichever comes first. If the power supply is
voltage limited, it operates in the CV mode. If the power supply is current
limited, it operates in the 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 the blue numbers to set the voltage and current |
limit.
4| Readback numbers| Voltage and current readback from the power supply,
the actual voltage and current being supplied to the external 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 is programmed to generate one of five
different signals, each with optional modulation.
Sine Wave
The Sine wave is the simplest dynamic signal in the Moku. It features
extremely low harmonic distortion; it’s very close to a pure single frequency.
The Sine wave can be modulated by all available modulation types. Moreover, it
forms the basis of the “Internal” selectable modulation source, providing a
modulating waveform regardless of whether either channel of the Moku is
currently outputting a Sine wave.
Square Wave
The Square wave is a low-jitter waveform with a variable duty cycle and high
slew rates. The high analogue bandwidth of the Moku gives very sharp rise and
fall times, highly desirable in many applications. If you require slew-rate
limits or variable duty cycle in your application, see Pulse Wave below.
Ramp Wave
The Ramp wave consists of linear ramps from low level to high and back again.
The ratio between the time spent rising and the overall period is referred to
as the symmetry. If you require configurable dwell times at the high or low
levels but common rise and fall times, you may use the Pulse Wave with large
edge times.
Pulse Wave
The Pulse wave is like the Square wave but has configurable edge times (rise
and fall time). The trade-off is that at high frequency, Pulse has slightly
worse edge jitter behaviour compared to the Square wave.
DC
Provides a high precision, fixed reference voltage at the output.
Waveform Parameters
Amplitude
Applicable To: Sine, Square, Ramp, Pulse Amplitude is specified as a Peak-to-
Peak value; that is, the high level minus the low level. If you wish to
specify the high and low levels explicitly, tap the Amplitude pill then the
Toggle Arrows in the parameter bar; or just tap the Amplitude label in the
Settings Drawer to toggle between the two representations.
Frequency
Applicable To: Sine, Square, Ramp, Pulse Specified in Hertz. Can also be
represented as period in seconds by tapping the Frequency label in the
Settings Drawer, or the Toggle Arrows in the parameter bar.
Offset
Applicable To: Sine, Square, Ramp, Pulse Average value of the Sine wave over
time. The alternative representation of this parameter is Low Level, which
combined with High Level also specifies Amplitude.
Phase
Applicable To: Sine, Square, Ramp, PulseDefines the phase of the waveform with
respect to the Moku’s internal reference. By tapping the “Sync Phase” button
in the Settings Drawer, this phase also becomes relative to the other output
channel.
Symmetry
Applicable To: RampRatio, in percent, between the time spent on the rising
edge and the overall period. In the limit of 0% and 100% symmetry, the ramp
wave becomes a sawtooth (zero1 rise and fall times respectively).
Pulse Width
Applicable To: PulsePositive width of the pulse. Any specified Edge Time is
split equally between the Pulse Width and the rest of the cycle; that is, duty
cycle is preserved when altering Edge Time.
Applicable To: Pulse
Time taken to transition from low level to high and vice-versa. This limits
the slew rate of the signal which can be advantageous in some applications.
Edge Time is split between high and low time equally, preserving duty cycle.
Duty Cycle
Applicable To: Square
The percentage of one period that the signal is active, or non-zero. This is
similar to pulse width except that the edge time is not factored into the duty
cycle due to the fast rise and fall times.
DC Level
Applicable To: DC Fixed voltage to output.
Modulation Types and Trigger Modes
Modulation Sources
Each modulation type can be driven by one of three sources.
Internal
Modulation is driven by an internally-generated sine wave of configurable
frequency. The amplitude of this wave is “full range”, in that it will
modulate to the depth specified when configuring the modulation type.
Input
Modulation for a given channel is driven by the corresponding analogue input
(i.e. Output 1 can only be modulated from Input 1, Output 2 from Input 2). The
depth is specified per volt on the input.
Output
Modulation for a given channel is driven by the opposite analogue output (i.e.
Output 1 is modulated by the waveform on Output 2 and vice-versa). This allows
the user to doubly-modulate a signal by modulating a signal on one channel,
then using that signal to modulate the opposite channel. This can be useful
for example when you wish to generate an “ideal” modulated signal on one
channel, but then perturb the phase, frequency or amplitude in order to test a
system’s response.
Trigger Sources
Burst and Sweep modes depend on the detection of a trigger event. There are
three possible sources for this event.
Internal
The trigger event is generated automatically at a given rate (specified
period).
External
A rising edge on the back-panel External Trigger Input is used as the trigger
source. For trigger level and precision characteristics, refer to the Moku:Lab
Technical Specifications available at
www.liquidinstruments.com.
Input
The corresponding Analogue input is monitored for a rising edge past the
specified voltage. Output 1 can only be triggered from Input 1; Output 2 from
Input 2.
Output
The opposite Analogue output is monitored for a rising edge past the specified
voltage. Combined with the fact that that opposite output can in turn be
modulated from a variety of sources, this provides extremely flexible control
of the trigger period (included for example changing period based on an
external voltage).
Amplitude Modulation
Applicable To: Sine, Square, Ramp, Pulse Amplitude modulation will change the
amplitude of the generated signal proportionally to the modulation input. The
actual proportion changed is called the modulation depth, the units of which
depend on the modulation source (see discussion of sources above).
Frequency Modulation
Applicable To: Sine, Square, Pulse Frequency modulation will change the
frequency of the generated signal proportionally to the modulation input. The
change in frequency caused by a given input is called the modulation depth and
has units of Hertz or Hertz per Volt depending on the modulation source used.
Phase Modulation
Applicable To: Sine, Square, Pulse Phase modulation will change the phase of
the generated signal proportionally to the modulation input. The change in
frequency caused by a given input is called the modulation depth and has units
of Degrees or Degrees per Volt depending on the modulation source used.
Burst Mode
Applicable To: Sine, Square, Pulse In burst mode, a trigger event causes the
given output to begin generating its configured waveform. Burst requires you
to specify a sub-mode that defines if or when the generation ends. N-Cycle:
The waveform will stop being generated after the specified number of cycles,
at which time is will re-arm and become ready to receive a new trigger. Gated:
The waveform will continue to be generated while-ever the trigger signal is
high (level-triggered). Start: The waveform generation begins on a trigger
signal but will continue indefinitely.
Sweep Mode
Applicable To: Sine, Square, Pulse Sweep mode provides a frequency modulation
of the input waveform, where the modulation waveform is a ramp wave that
begins generation on the detection of a trigger signal. That is, when a
trigger is detected, waveform generation will begin at the Start frequency and
sweep (or “chirp”) to the End frequency over a given duration.
Sweep mode has three configurable parameters:
Start Frequency: Initial frequency of the output waveform, immediately on
detection of a trigger. Note that in sweep mode, the waveform itself cannot
have a frequency set independently; its frequency parameters are completely
defined by the sweep.
End Frequency:
Final frequency of the output waveform, duration sections after the trigger
has been detected.
Duration:
The time taken to sweep from Start to End frequency. Upon completion of the
sweep, the sweep circuit will re-arm and be ready to receive a new trigger
input.
References
Read User Manual Online (PDF format)
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