lockin module¶
Continuouswave generation and measurement.
Detailed information is provided in the documentation for each class.
Use the hardware in continuouswave mode. 

Specialpurpose version of 

Settings of a lockin input group. 

Settings of a lockin output group. 

Settings of a symmetric lockin group. 
Converter modes (reexported from hardware
module):
Converter sampling rates (reexported from hardware
module):
 class presto.lockin.AdcFSample(value)¶
Sampling rate setting for analogtodigital converters (ADC), i.e. input channels
See
AdcFSample
for full documentation
 class presto.lockin.DacFSample(value)¶
Sampling rate setting for digitaltoanalog converters (DAC), i.e. output channels
See
DacFSample
for full documentation
Lockin class¶
 class presto.lockin.Lockin(*, ext_ref_clk=False, force_reload=False, dry_run=False, address=None, port=None, adc_mode=AdcMode.Direct, adc_fsample=AdcFSample.G2, dac_mode=DacMode.Direct, dac_fsample=DacFSample.G4, force_config=False)¶
Use the hardware in continuouswave mode.
Warning
Create only one instance at a time. This class is designed to be instantiated with Python’s with statement, see Examples section.
 Parameters
ext_ref_clk (optional) – if
None
orFalse
use internal reference clock; ifTrue
use external reference clock (10 MHz); iffloat
orint
use external reference clock at ext_ref_clk Hzforce_reload (bool, optional) – if
True
reconfigure clock and reload firmware even if there’s no change from the previous settings.dry_run (bool, optional) – if
False
don’t connect to hardware, for testing only.address (str, optional) – IP address or hostname of the hardware. If
None
, use factory default “192.168.42.50”.port (int, optional) – port number of the server running on the hardware. If
None
, use factory default 7878.adc_mode (hardware.AdcMode or list, optional) – configure the inputs to sample in direct mode (default), or to use the digital mixers for downconversion. See Notes.
adc_fsample (hardware.AdcFSample or list, optional) – configure the inputs sampling rate (default 2 GS/s). See Notes.
dac_mode (hardware.DacMode or list, optional) – configure the outputs to work in direct mode (default), to use the digital mixers for upconversion. See Notes.
dac_fsample (hardware.DacFSample or list, optional) – configure the outputs sampling rate (default 4 GS/s). See Notes.
force_config (bool, optional) – if
True
skip checks on DacModes not recommended for high DAC sampling rates.
 Raises
ValueError – if adc_mode or dac_mode are not valid Converter modes; if adc_fsample or dac_fsample are not valid Converter rates.
Notes
In all the Examples, it is assumed that the imports
import numpy as np
andfrom presto import lockin
have been performed, and that this class has been instantiated in the formlck = lockin.Lockin()
, or, much much better, using thewith lockin.Lockin() as lck
construct as below.For valid values of adc_mode and dac_mode, see Converter modes. For valid values of adc_fsample and dac_fsample, see Converter rates. For advanced configuration, e.g. different converter rates on different ports, see Advanced tile configuration.
 VARIANT = 7¶
 add_input_group(port, nr_freq)¶
Create and return a new
input group
 Parameters
 Return type
 add_output_group(ports, nr_freq)¶
Create and return a new
output group
 Parameters
 Return type
 apply_settings()¶
Apply the settings to the hardware.
Notes
Prior to a call to this function, any change of settings has no effect on the hardware.
 check_current_consumption()¶
 close()¶
Gracely disconnect from the hardware.
Call this method if the class was instantiated without a with statement. This method is called automatically when exiting a
with
block and before the object is destructed.
 get_Tm()¶
Get measurement time.
The inverse of the measurement bandwidth.
 Returns
Tm – Measurement time in seconds.
 Return type
See also
 get_fs(which)¶
Get sampling frequency for which converter.
 Parameters
which (str) – “adc” for input and “dac” for output.
 Returns
fs
 Return type
 Raises
ValueError – if which is unknown.
 get_ns(which='adc')¶
Get number of samples per lockin window.
The sampling rate divided by the measurement bandwidth.
 Returns
ns
 Return type
 get_pixels(n, summed=False, fir_coeffs=None, nsum=250, quiet=False)¶
Get lockin packets (pixels) from the hardware.
 Parameters
n (int) – the number of lockin packets to measure.
summed (bool, optional) – when True, calculate on the hardware the mean and standard deviation of the acquired data in chunks of nsum lockin packets.
fir_coeffs (list of float, optional) – coefficients for FIR filter to be applied to measured data. 43 coefficients must be provided, or pass None (default) to disable the filter. See also Notes and Examples sections.
nsum (int, optional) – ignored if summed=False. How many lockin packets (at rate
get_df()
) The resulting data rate will beget_df()
/ nsum.quiet (
bool
) – if True, don’t check for inputs out of range
 Returns
dictionary with key port and value depending on the value of summed.
The key is always:
port (
int
): input port measured
When summed=False (default), the value is a tuple of:
freqs (
np.ndarray
, dtype=np.float64): frequencies at which the lockin measurement was done.pixels (
np.ndarray
, dtype=np.complex128): measured lockin data in ratio of fullscale input. shape is (n, len(freqs)). When using digital downconversion (adc_mode isAdcMode.Mixed
), these are the pixels of the I port of the digital mixer.pixels_q (
np.ndarray
, dtype=np.complex128): only present when using digital downconversion (adc_mode isAdcMode.Mixed
), these are the pixels of the Q port of the digital mixer.
When summed=True, the value is a tuple of:
freqs (
np.ndarray
, dtype=np.float64): frequencies at which the lockin measurement was done.mean_I (
np.ndarray
, dtype=np.complex128): calculated mean of nsum consecutive lockin packets from the I port of the digital downconversion. shape is (n, len(freqs)).std_I (
np.ndarray
, dtype=np.complex128): calculated standard deviation of nsum consecutive lockin packets from the I port of the digital downconversion. shape is (n, len(freqs)). The standard deviation has a real and an imaginary part; abs(std) is the total standard deviation according to Complex random variable.mean_Q (
np.ndarray
, dtype=np.complex128): same as mean_I, but from the Q port.std_Q (
np.ndarray
, dtype=np.complex128): same as std_I, but from the Q port.
 Return type
 Raises
RuntimeError – if
apply_settings()
was not called after changing some setting
Notes
This method locks execution until at least n measured packets are available.
summed=True is only implemented when using digital downconversion (adc_mode is
AdcMode.Mixed
).Useful functions for computing the coefficients fir_coeffs for the FIR filter are
remez
andfirwin
in thescipy.signal
module.Examples
Measure 1k lockin packets, and lowpass filter the measured data:
>>> from scipy.signal import firwin >>> coeffs = firwin(43, 80e3, fs=lck.get_df()) # lowpass filter with 80 kHz cutoff >>> data = lck.get_pixels(n=1000, fir_coeffs=coeffs) >>> freqs, (pixels_I, pixels_Q) = data[input_port] >>> freqs.shape (32,) >>> pixels_I.shape (1000, 32) >>> pixels_Q.shape (1000, 32)
Measure 100k lockin packets, and compute mean and standard deviation in chunks of 100 packets:
>>> data = lck.get_pixels(n=1000, summed=True, nsum=100) >>> freqs, (mean_I, std_I, mean_Q, std_Q) = data[input_port] >>> freqs.shape (32,) >>> mean_I.shape (1000, 32) >>> std_Q.shape (1000, 32)
 set_df(df)¶
Set measurement bandwith.
The new setting is not applied until
apply_settings()
is called! Parameters
df (float) – Measurement bandwith in Hz.
Notes
Nontuned measurement bandwidths can’t be set in hardware. When passing a nontuned df, the closest tuned value will be set in hardware. To avoid confusion, it is recommended to explicitly tune df before calling this method.
See also
 set_dither(state, output_ports)¶
Add pseudorandom noise to the generated output.
Can improve harmonic and intermodulation distortion when working with small output amplitudes.
The change is active immediately
 set_phase_reset(reset_phase)¶
Reset the phase of the reference signals at the end of every lockin window.
The new setting is not applied until
apply_settings()
is called!This setting is ON by default. See Notes in
tune()
for rationale. Return type
 set_trigger_out(states, delay=0.0, width=1e07)¶
Output a trigger on the digital output ports at the start of every demodulation or summing window.
Times will be rounded to closest integer multiple of
get_clk_T()
. Parameters
states (
Union
[int
,List
[int
]]) – enable/disable the trigger on each of the digital output ports. Valid values are: 0 no trigger output, 1 trigger for each new lockin window, 2 trigger for each new sum window (mean and std)delay (
float
) – delay trigger rising edge from start of lockin window, in secondswidth (
float
) – triggerhigh duration, in seconds
 Raises
ValueError – if delay and width are negative, or too large
Examples
Output a 100ns trigger on port 1 every summing window and on port 2 every demodulation window:
>>> lck.set_trigger_out([2, 1])
 Return type
 tune(f, df)¶
Perform standard level of tuning.
This provides frequencies closer to the requested ones, with a level of Fourier leakage that is adequate to most experiments. See Notes.
 Parameters
 Returns
f_tuned (float or numpy.ndarray) – Tuned frequencies in Hz
df_tuned (float) – Tuned measurement bandwith in Hz
See also
tune_perfect
perfect tuning
set_phase_reset
enable/disable phase reset every 1/df
Notes
First, this level of tuning forces the measurement bandwith df to be a divisor of the sampling frequency fs, i.e. there is an integer number of samples ns = fs/df_tuned in each lockin measurement window. Second, the tuning forces each frequency f to be integer multiple of the measurement bandwith df_tuned, i.e. there is an integer number n = f_tuned/df_tuned of oscillations within each measurement window.
In theory, this level of tuning allows for measurement without Fourier leakage, or spectral leakage. In practice, however, not every value of f_tuned can be represented exactly in the hardware. With this level of tuning, the frequency that is actually set in hardware f_set is slightly different from the tuned frequency f_tuned. Therefore, the ratio f_set/df_tuned is not an integer, and some Fourier leakage occurs. To avoid longterm phase drift, the phase of the oscillation at frequency f_set is reset at the end of each lockin window (every 1/df_tuned). Use
set_phase_reset()
to disable this behavior.Nonetheless, the difference between f_set and f_tuned is actually really small: the worstcase error is get_fs(“dac”)/2/2**48, on the order of a single microhertz (\(1 \mathrm{\mu Hz}\))! For most common applications, the resulting Fourier leakage and the phasereset glitches are well below the noise level. If however, this is not acceptable, see
tune_perfect()
.
 tune_perfect(f, df)¶
Perform perfect level of tuning.
This provides frequencies that might be further from the requested ones, but with zero Fourier leakage. See Notes.
 Parameters
 Returns
f_tuned (float or numpy.ndarray) – Tuned frequency/ies in Hz
df_tuned (float) – Tuned measurement bandwith in Hz
See also
tune
standard tuning
Notes
First, this level of tuning forces the measurement bandwith df to divide the sampling frequency fs by a power of 2, i.e. the number of samples in each lockin measurement window is a power of 2: ns = fs/df_tuned = 2**m. Second, the tuning forces each frequency f to be integer multiple of the measurement bandwith df_tuned, i.e. there is an integer number n = f_tuned/df_tuned of oscillations within each measurement window.
This level of tuning always allows for measurement without Fourier leakage, or spectral leakage, and guarantees that f_tuned can be represented exactly in the hardware.
SymmetricLockin class¶
 class presto.lockin.SymmetricLockin(*, ext_ref_clk=False, force_reload=False, dry_run=False, address=None, port=None, adc_mode=AdcMode.Mixed, adc_fsample=AdcFSample.G2, dac_mode=DacMode.Mixed02, dac_fsample=DacFSample.G4, force_config=False)¶
Specialpurpose version of
Lockin
with same frequencies on input and output (symmetric).The symmetric lockin only supports Mixed mode. The digital mixers are configured for singlesideband upconversion and downconversion, using the upper sideband. The frequency of the output tones will therefore be the sum of the IF frequency set with
set_frequencies
and of the LO frequency set withhardware.configure_mixer
.Warning
Create only one instance at a time. This class is designed to be instantiated with Python’s with statement, see Examples section.
 Parameters
ext_ref_clk (optional) – if
None
orFalse
use internal reference clock; ifTrue
use external reference clock (10 MHz); iffloat
orint
use external reference clock at ext_ref_clk Hzforce_reload (bool, optional) – if
True
reconfigure clock and reload firmware even if there’s no change from the previous settings.dry_run (bool, optional) – if
False
don’t connect to hardware, for testing only.address (str, optional) – IP address or hostname of the hardware. If
None
, use factory default “192.168.42.50”.port (int, optional) – port number of the server running on the hardware. If
None
, use factory default 7878.adc_mode (hardware.AdcMode or list, optional) – configure the inputs to use the digital mixers for downconversion. Direct mode is not supported.
adc_fsample (hardware.AdcFSample or list, optional) – configure the inputs sampling rate (default 2 GS/s). See Notes.
dac_mode (hardware.DacMode or list, optional) – configure the outputs to use the digital mixers for upconversion. Direct mode is not supported. See Notes.
dac_fsample (hardware.DacFSample or list, optional) – configure the outputs sampling rate (default 4 GS/s). See Notes.
force_config (bool, optional) – if
True
skip checks on DacModes not recommended for high DAC sampling rates.
 Raises
ValueError – if adc_mode or dac_mode are not valid Converter modes; if adc_fsample or dac_fsample are not valid Converter rates.
Notes
In all the Examples, it is assumed that the imports
import numpy as np
andfrom presto import lockin
have been performed, and that this class has been instantiated in the formlck = lockin.SymmetricLockin()
, or, much much better, using thewith lockin.SymmetricLockin() as lck
construct as below.For valid values of adc_mode and dac_mode, see Converter modes. For valid values of adc_fsample and dac_fsample, see Converter rates. For advanced configuration, e.g. different converter rates on different ports, see Advanced tile configuration.
 add_symmetric_group(input_port, output_ports, nr_freq)¶
Create and return a new
symmetric group
 Parameters
 Return type
 apply_settings()¶
Apply the settings to the hardware.
Notes
Prior to a call to this function, any change of settings has no effect on the hardware.
 close()¶
Gracely disconnect from the hardware.
Call this method if the class was instantiated without a with statement. This method is called automatically when exiting a
with
block and before the object is destructed.
 get_Tm()¶
Get measurement time.
The inverse of the measurement bandwidth.
 Returns
Tm – Measurement time in seconds.
 Return type
See also
 get_fs(which)¶
Get sampling frequency for which converter.
 Parameters
which (str) – “adc” for input and “dac” for output.
 Returns
fs
 Return type
 Raises
ValueError – if which is unknown.
 get_ns(which='adc')¶
Get number of samples per lockin window.
The sampling rate divided by the measurement bandwidth.
 Returns
ns
 Return type
 get_pixels(n, summed=False, fir_coeffs=None, nsum=250, quiet=False)¶
Get lockin packets (pixels) from the hardware.
 Parameters
n (int) – the number of lockin packets to measure. When summed=True, n is the number of means and standard deviation acquired: the number of lockin packets measured will be n*nsum.
summed (bool, optional) – when True, calculate on the hardware the mean and standard deviation of the acquired data in chunks of nsum lockin packets.
fir_coeffs (list of float, optional) – coefficients for FIR filter to be applied to measured data. 43 coefficients must be provided, or pass None (default) to disable the filter. See also Notes and Examples sections.
nsum (int, optional) – ignored if summed=False. How many lockin packets (at rate
get_df()
) The resulting data rate will beget_df()
/ nsum.quiet (
bool
) – if True, don’t check for inputs out of range
 Returns
pixels – dictionary with key port and value depending on the value of summed.
The key is always:
port (
int
): input port measured
When summed=False (default), the value is a tuple of:
freqs (
np.ndarray
, dtype=np.float64): frequencies at which the lockin measurement was done.pixels (
np.ndarray
, dtype=np.complex128): measured lockin data in ratio of fullscale input. shape is (n, len(freqs)).
When summed=True, the value is a tuple of:
freqs (
np.ndarray
, dtype=np.float64): frequencies at which the lockin measurement was done.mean (
np.ndarray
, dtype=np.complex128): calculated mean of nsum consecutive lockin packets. shape is (n, len(freqs)).std (
np.ndarray
, dtype=np.complex128): calculated standard deviation of nsum consecutive lockin packets. shape is (n, len(freqs)). The standard deviation has a real and an imaginary part; abs(std) is the total standard deviation according to Complex random variable.
 Return type
 Raises
RuntimeError – if
apply_settings()
was not called after changing some setting
Notes
This method locks execution until at least n measured packets are available.
Useful functions for computing the coefficients fir_coeffs for the FIR filter are
remez
andfirwin
in thescipy.signal
module.Examples
Measure 1k lockin packets, and lowpass filter the measured data:
>>> from scipy.signal import firwin >>> coeffs = firwin(43, 80e3, fs=lck.get_df()) # lowpass filter with 80 kHz cutoff >>> data = lck.get_pixels(n=1000, fir_coeffs=coeffs) >>> freqs, pixels = data[input_port] >>> freqs.shape (32,) >>> pixels.shape (1000, 32)
Measure 100k lockin packets, and compute mean and standard deviation in chunks of 100 packets:
>>> data = lck.get_pixels(n=1000, summed=True, nsum=100) >>> freqs, mean, std = data[input_port] >>> freqs.shape (32,) >>> mean.shape (1000, 32) >>> std.shape (1000, 32)
 set_df(df)¶
Set measurement bandwith.
The new setting is not applied until
apply_settings()
is called! Parameters
df (float) – Measurement bandwith in Hz.
Notes
Nontuned measurement bandwidths can’t be set in hardware. When passing a nontuned df, the closest tuned value will be set in hardware. To avoid confusion, it is recommended to explicitly tune df before calling this method.
See also
 set_dither(state, output_ports)¶
Add pseudorandom noise to the generated output.
Can improve harmonic and intermodulation distortion when working with small output amplitudes.
The change is active immediately
 set_phase_reset(reset_phase)¶
Reset the phase of the reference signals at the end of every lockin window.
The new setting is not applied until
apply_settings()
is called!This setting is ON by default. See Notes in
tune()
for rationale. Return type
 set_trigger_out(states, delay=0.0, width=1e07)¶
Output a trigger on the digital output ports at the start of every demodulation or summing window.
Times will be rounded to closest integer multiple of
get_clk_T()
. Parameters
states (
Union
[int
,List
[int
]]) – enable/disable the trigger on each of the digital output ports. Valid values are: 0 no trigger output, 1 trigger for each new lockin window, 2 trigger for each new sum window (mean and std)delay (
float
) – delay trigger rising edge from start of lockin window, in secondswidth (
float
) – triggerhigh duration, in seconds
 Raises
ValueError – if delay and width are negative, or too large
Examples
Output a 100ns trigger on port 1 every summing window and on port 2 every demodulation window:
>>> lck.set_trigger_out([2, 1])
 Return type
 tune(f, df)¶
Perform standard level of tuning.
This provides frequencies closer to the requested ones, with a level of Fourier leakage that is adequate to most experiments. See Notes.
 Parameters
 Returns
f_tuned (float or numpy.ndarray) – Tuned frequencies in Hz
df_tuned (float) – Tuned measurement bandwith in Hz
See also
tune_perfect
perfect tuning
set_phase_reset
enable/disable phase reset every 1/df
Notes
First, this level of tuning forces the measurement bandwith df to be a divisor of the sampling frequency fs, i.e. there is an integer number of samples ns = fs/df_tuned in each lockin measurement window. Second, the tuning forces each frequency f to be integer multiple of the measurement bandwith df_tuned, i.e. there is an integer number n = f_tuned/df_tuned of oscillations within each measurement window.
In theory, this level of tuning allows for measurement without Fourier leakage, or spectral leakage. In practice, however, not every value of f_tuned can be represented exactly in the hardware. With this level of tuning, the frequency that is actually set in hardware f_set is slightly different from the tuned frequency f_tuned. Therefore, the ratio f_set/df_tuned is not an integer, and some Fourier leakage occurs. To avoid longterm phase drift, the phase of the oscillation at frequency f_set is reset at the end of each lockin window (every 1/df_tuned). Use
set_phase_reset()
to disable this behavior.Nonetheless, the difference between f_set and f_tuned is actually really small: the worstcase error is get_fs(“dac”)/2/2**48, on the order of a single microhertz (\(1 \mathrm{\mu Hz}\))! For most common applications, the resulting Fourier leakage and the phasereset glitches are well below the noise level. If however, this is not acceptable, see
tune_perfect()
.
 tune_perfect(f, df)¶
Perform perfect level of tuning.
This provides frequencies that might be further from the requested ones, but with zero Fourier leakage. See Notes.
 Parameters
 Returns
f_tuned (float or numpy.ndarray) – Tuned frequency/ies in Hz
df_tuned (float) – Tuned measurement bandwith in Hz
See also
tune
standard tuning
Notes
First, this level of tuning forces the measurement bandwith df to divide the sampling frequency fs by a power of 2, i.e. the number of samples in each lockin measurement window is a power of 2: ns = fs/df_tuned = 2**m. Second, the tuning forces each frequency f to be integer multiple of the measurement bandwith df_tuned, i.e. there is an integer number n = f_tuned/df_tuned of oscillations within each measurement window.
This level of tuning always allows for measurement without Fourier leakage, or spectral leakage, and guarantees that f_tuned can be represented exactly in the hardware.
Input and output groups¶
 class presto.lockin.InputGroup(port, nr_freq, lockin)¶
Settings of a lockin input group.
Used as return type by
Lockin.add_input_group()
. Contains access functions for changing the settings of this input group.The lockin input is divided into 16 groups. Each group is capable of demodulating 12 different quadratures, for a total of 192 demodulations (96 I/Q pairs). Each demodulator has a configurable frequency and phase. Each group can acquire data from a single (configurable) input port.
Warning
Do not instantiate this class directly! Call
Lockin.add_input_group()
to obtain a valid instance. get_frequencies()¶
Get the lockin input frequencies.
 Returns
freqs – frequencies in Hz. dtype is
numpy.float64
 Return type
 get_phases(*, deg=False)¶
Get the lockin input phases.
 set_frequencies(freqs)¶
Set the lockin input frequencies.
The new setting is not applied until
Lockin.apply_settings()
is called! Parameters
freqs (float or array_like) – frequency/ies in Hz. If less than available number of frequencies, the rest is set to zero.
 Return type
Notes
This function performs no tuning, make sure freqs are tuned to the user needs before calling this function.
See also
 set_phases(phases, *, deg=False)¶
Set the lockin input phases.
The new setting is not applied until
Lockin.apply_settings()
is called! Parameters
phases (float or array_like) – phases in rad/deg. If less than available number of frequencies, set the rest to zero. When using the digital mixers (adc_mode is
AdcMode.Mixed
), sets the phase of both the I and the Q port of the downconversion mixer.deg (bool, optional) – if
True
, set the phases in degrees in [180.0, +180.0]; ifFalse
(default) radians in [π, +π].
 Return type
 class presto.lockin.OutputGroup(ports, nr_freq, lockin)¶
Settings of a lockin output group.
Used as return type by
Lockin.add_output_group()
. Contains access functions for changing the settings of this output group.The lockin output is divided into 16 groups. Each group is capable of driving tones at 12 different frequencies, for a total of 192 frequencies. Each tone has a configurable frequency, phase and amplitude. Each group can be output on one or more output ports.
Warning
Do not instantiate this class directly! Call
Lockin.add_output_group()
to obtain a valid instance. get_amplitudes()¶
Get the lockin output amplitudes.
 Returns
amps – amplitudes for each frequency with +/ 1.0 being full scale. dtype is
numpy.float64
. Return type
 get_frequencies()¶
Get the lockin output frequencies.
 Returns
freqs – frequencies in Hz. dtype is
numpy.float64
 Return type
 get_phases(*, deg=False)¶
Get the lockin output phases.
 set_amplitudes(amps)¶
Set the lockin output amplitudes.
The new setting is not applied until
Lockin.apply_settings()
is called! Parameters
amps (float or array_like) – amplitudes with +/ 1.0 being full scale. If less than available number of frequencies, set the rest to zero.
 Return type
 set_frequencies(freqs)¶
Set the lockin output frequencies.
The new setting is not applied until
Lockin.apply_settings()
is called! Parameters
freqs (float or array_like) – frequency/ies in Hz. If less than available number of frequencies, the rest is set to zero.
 Return type
Notes
This function performs no tuning, make sure freqs are tuned to the user needs before calling this function.
See also
 set_phases(phases, phases_q=None, *, deg=False)¶
Set the lockin output phases.
The new setting is not applied until
Lockin.apply_settings()
is called! Parameters
phases (float or array_like) – phases in rad/deg. If less than available number of frequencies, set the rest to zero. When using the digital mixers (dac_mode is one of
DacMode.Mixedxx
), sets the phase of the I port of the upconversion mixer.phases_q (float or array_like, optional) – when using the digital mixers, sets the phase of the Q port of the upconversion mixer. In direct mode (dac_mode is
DacMode.Direct
), setting phases_q throws aValueError
exception.deg (bool, optional) – if
True
, set the phases in degrees in [180.0, +180.0]; ifFalse
(default) radians in [π, +π].
 Return type
 class presto.lockin.SymmetricGroup(input_port, output_ports, nr_freq, lockin)¶
Settings of a symmetric lockin group.
Used as return type by
SymmetricLockin.add_symmetric_group()
. Contains access functions for changing the settings of this inputoutput group.The lockin output is divided into 16 groups. Each group is capable of driving tones at 12 different frequencies, for a total of 192 frequencies. Each tone has a configurable frequency, phase and amplitude. Each group can be output on one or more output ports, and acquire data from a single (configurable) input port.
Warning
Do not instantiate this class directly! Call
SymmetricLockin.add_symmetric_group()
to obtain a valid instance. get_amplitudes()¶
Get the lockin output amplitudes.
 Returns
amps – amplitudes for each frequency with +/ 1.0 being full scale. dtype is
numpy.float64
. Return type
 get_frequencies()¶
Get the lockin frequencies.
 Returns
freqs – frequencies in Hz. dtype is
numpy.float64
 Return type
 get_phases(*, deg=False)¶
Get the lockin output phases.
 set_amplitudes(amps)¶
Set the lockin output amplitudes.
The new setting is not applied until
Lockin.apply_settings()
is called! Parameters
amps (float or array_like) – amplitudes with +/ 1.0 being full scale. If less than available number of frequencies, set the rest to zero.
 Return type
 set_frequencies(freqs)¶
Set the lockin frequencies.
The new setting is not applied until
Lockin.apply_settings()
is called! Parameters
freqs (float or array_like) – frequency/ies in Hz. If less than available number of frequencies, the rest is set to zero.
Notes
This function performs no tuning, make sure freqs are tuned to the user needs before calling this function.
 Return type
See also
 set_phases(phases, *, deg=False)¶
Set the lockin output phases.
The new setting is not applied until
Lockin.apply_settings()
is called! Parameters
 Return type