OPX1000 Front End Modules (FEMs)¶

Low Frequency FEM (LF-FEM)¶

The LF-FEM module features 8 analog outputs at a sampling rate of 2 Gs/s, 2 analog inputs at a sampling rate of 2 Gs/s, and 8 digital outputs at a sampling rate of 1 Gs/s. For more information about the panel and the connectors, see OPX1000 Hardware.

Sampling Rate¶

The analog outputs and inputs sampling rate can be defined to be 1 or 2 Gs/s, by setting the field sampling_rate to be either 1e9 (default) or 2e9 in the config at the port. This has the following implications:

When the output port is set to 1e9, the PPU upsamples the output from 1 Gs/s to 2 Gs/s at which the DACs operate. This is controlled by an additional field upsampling_mode:
- mw - In this mode, the upsampling is done by passing the 1 Gs/s samples through a 14-taps Dolph-Chebyshev filter which is optimized to reduce spurs and produce clean MW signals. This is the recommended mode whenever the output is expected to have an intermediate frequency larger than 100MH.
- pulsed - In this mode, the upsampling is done by passing the 1 Gs/s samples through a 2 taps moving average filter which is optimized to produce clean step responses. This is the recommended mode whenever the output is not expected to have an intermediate frequency.
Any element using an output port set to 2e9 will consume double the amount of threads.
Any element using an output port set to 1e9 will be limited to a frequency of 500 MHz, and the waveforms' sampling rate is limited to 1e9.
Any measurement done on an input port set to 1e9 will produce an ADC stream at 1e9 and the demodulation will be limited to 500MHz.

Note

If an element is using output ports set to 1e9, and input ports set to 2e9, it will also consume double the amount of threads.

Output Mode¶

The analog outputs can operate in one of two modes, set in the config at the output port using the field output_mode:

direct - The output range is between -0.5V to 0.5V.
amplified - The output range is between -2.5V to 2.5V, the hardware filters are optimized for a cleaner step response.

Microwave FEM (MW-FEM)¶

The MW-FEM module features 8 analog outputs at a quadrature sampling rate of 1 or 2 Gs/s which are digitally unconverted to MW frequencies, 2 analog inputs at a sampling rate of 2 Gs/s, and 8 digital outputs at a sampling rate of 1 Gs/s. For more information about the panel and the connectors, see ADD_LINK_HERE.

Note

The quadrature sampling rate for the MW output ports defines the rate at which samples are sent from the PPU to the DACs, per quadrature. This is then being digitally upconvertered to GHz frequencies.

Sampling Rate¶

The analog outputs and inputs sampling rate can be defined to be 1 or 2 Gs/s, by setting the field sampling_rate to be either 1e9 (default) or 2e9 in the config at the port. This has the following implications:

An output port set to 2e9 can only have a single upconverter.
Any element using an output port set to 2e9 will consume double the amount of threads.
Any element using an output port set to 1e9 will be limited to a frequency of 500 MHz, and the waveforms' sampling rate is limited to 1e9.
Any measurement done on an input port set to 1e9 will produce an ADC stream at 1e9 and the demodulation will be limited to 500MHz.

Note

If an element is using output ports set to 1e9, and input ports set to 2e9, it will also consume double the amount of threads.

Bands¶

Each analog port must specifics the band at which it operates in the config, the supported bands are:

1 - 50 MHz - 5.5 GHz
2 - 4.5 GHz - 7.5 GHz
3 - 6.5 GHz - 10.5 GHz

In addition, the following pairs on analog ports are coupled:

Out 1 & In 1
Out 2 & Out 3
Out 4 & Out 5
Out 6 & Out 7
Out 8 & In 2

Coupled ports must be in the same band, or in bands 1 and 3.

Upconverters & Downconverters¶

Each analog output port must define either a upconverter_frequency field with a frequency in the port's band, or a upconverters field, with up to 2 upconverters per port:

'upconverters': {
    1: {'frequency': 5e9},
    2: {'frequency': 6e9},
}

In the elements MWInput field, the user can set the upconverter field, the default is 1.

Each analog input port must define a downconverter_frequency field with a frequency in the port's band.

Output Power¶

The analog output power is defined using the field full_scale_power_dbm, which can be set between -41 and 10 dBm with a 3 dB granularity. This will set the power delivered to a 50 ohm load when the waveform is set to full scale ([-1, 1]).

Note

To calculate the voltage that will be seen on a scope set to 50 ohm, first convert the power to voltage:

\[\begin{eqnarray} x_{mw} = 10^{\frac{x_{dbm}}{10}} \\ x_v = \sqrt{\frac{2 \cdot 50 \cdot x_{mw}}{1000}} \end{eqnarray}\]

Where \(x_{dbm}\) is the value written in the config. This is then multiplied by the waveform amplitude and any realtime modification done in QUA.