Functional Overview¶

This chapter provides the overview of the features provided by the SHFQC Instrument. Unless explicitly stated otherwise, all contents of the manual apply to both the original SHFQC as well as the SHFQC+. The first section contains the description of the functional diagram and the hardware and software feature list. The next section details the front panel and the back panel of the measurement instrument. The following section provides product selection and ordering support.

Features¶

The SHFQC+ Instrument consists of one Quantum Analyzer readout channel, and 6 Signal Generator control channels. Both types of channels consists of several interface units processing analog signals (dark blue color), and several internal units that process digital data (light blue color). On the Signal Generator channels, the internal units that process digital data are called Digital Signal Units (or DSUs). The interface units that connect to the front panel are depicted on the left-hand side and the units at the back panel are depicted on the right-hand side of the Figure. Arrows between the panels and the interface units indicate selected physical connections and data flow, whereas double arrows indicate complex-valued information processing. Information indicated in orange is linked to options that can be either ordered at purchase or upgraded later. The ordering guide details the available upgrade options for the SHFQC+ Qubit Controller and whether the option can be upgraded directly in the field.

Figure 1: SHFQC+ instrument functional diagram

Quantum Analyzer Channel¶

The Quantum Analyzer readout channel has signal generation (Readout Pulse Generator, Oscillator) and signal analysis (Sweeper, Qubit Measurement Unit) functionality, as well as a Monitor Scope. The digital, complex-valued signal from the signal generation is up-converted to microwave frequencies in the analog domain using the Quantum Analyzer Signal Output Module. After passing through the device under test, the analog signal is first down-converted and then digitized in the Quantum Analyzer Signal Input before the complex-valued signal is being analyzed in the Qubit Measurement Unit.

The Quantum Analyzer channel can be configured in two modes:

Qubit Readout

In the Qubit Readout mode, the Readout Pulse Generator outputs the sum of up to 16 individual, user-defined arbitrary waveforms that are stored in separate Waveform Memory blocks, controlled by the Generator Sequencer. In the Qubit Measurement Unit, the signal is then first integrated using up to 16 user-defined, complex-valued Integration Weight Memories. The results of the integration are then discriminated between different qubit states, and the results are forwarded to either the Signal Generator channels or other instruments in real time using either the 32-bit DIO or the ZSync links.

Spectroscopy

In the Spectroscopy mode, the Sweeper controls an Oscillator, hence a single frequency microwave signal is sent to the experiment. The Qubit Measurement Unit then correlates this signal with the original oscillator signal and displays transmission data in the Sweeper module.

Super-high-frequency Signal Inputs¶

Low-noise SHF Inputs, 0.5 - 8.5 GHz frequency range with 1 GHz bandwidth when using the RF path, DC - 800 MHz when using the LF path
Broadband double super-heterodyne frequency down-conversion, free from mixer calibration
Calibrated (Input) Power Range, selectable from -50 dBm to 10 dBm when using the RF path, from -30 dBm to +10 dBm when using the LF path

Super-high-frequency Signal Outputs¶

Low-noise SHF Outputs, 0.5 - 8.5 GHz frequency range with 1 GHz bandwidth when using the RF path, DC - 800 MHz when using the LF path
Broadband double super-heterodyne frequency up-conversion, free from mixer calibration
Calibrated (Output) Power Range, selectable from -30 dBm to 10 dBm when using the RF path, from -30 dBm to +5 dBm when using the LF path

Readout Pulse Generator¶

Arbitrary waveform capability
Advanced sequencing
- looping, branching
- advanced trigger control (time-staggered readout capability)
Up to 16 freely configurable waveform memory blocks of 4 kSa (total 64 kSa)

Qubit Measurement Unit¶

Up to 16 complex integrators with programmable Integration Weight memory (this requires the SHFQC-16W option.)
Multistate Discrimination for up to 4 states per qubit
Result Logger with real-time averaging and data logging.

Sweeper¶

Controls the numerical Oscillator for fast frequency sweeps in Spectroscopy mode
Displays the oscillator-correlated complex-valued data

Monitor Scope¶

Real-time scope to view Input Signals
Displays complex signals in time and frequency domain

Signal Generator Channel¶

Each of the 6 control channels has an arbitrary waveform generator AWG and Modulation functionality. The digital, complex-valued signal from the Digital Signal Unit is up-converted to microwave frequencies in the analog domain using the Signal Generator Signal Output Module.

Super-high-frequency Signal Outputs¶

Low-noise SHF Outputs, DC - 8.5 GHz frequency range, 1 GHz modulation bandwidth
Broadband double super-heterodyne frequency up-conversion
Calibrated (Output) Power Range, selectable from -30 dBm to 10 dBm when using the RF path and from -30 dBm to 5 dBm when using the LF path

Advanced Pulse Sequencer¶

Arbitrary Waveform Generator capability
Advanced sequencing
- looping, branching
- command table
- advanced trigger control
Digital modulation

Shared Resources¶

The Quantum Analyzer and Signal Generator channels share several functionalities that are used for communication (32-bit DIO, ZSync) and inter-channel synchronization (Hardware Trigger Engine).

Hardware Trigger Engine¶

shared between all channels and modes
2 Marker Outputs and Trigger Inputs of the Quantum Analyzer channel
1 Marker Output and Trigger Input for each Signal Generator channel

High-speed Connectivity¶

SMA connectors on front and back panel for triggers, signals and external clock
USB 3.0 high-speed host interface
Maintenance USB connection
LAN/Ethernet 1 Gbit/s controller interface
DIO: 32-bit digital input-output port
2 ZSync connectors for clock synchronization and fast data transfer
Clock input/output connectors (10 MHz)

Software Features¶

LabOne Graphic User Interface: Web-based with multi-instrument control
Zurich Instruments LabOne Q software for high-level programming of quantum computing experiments.
Data server with multi-client support
LabOne APIs, including Python, C, LabVIEW, MATLAB, .NET
Turnkey software and firmware features for fast system tune-up

Front Panel Tour¶

The front panel SMA connectors and control LEDs are arranged as shown in Figure 2 and listed in Table 1.

Figure 2: SHFQC+ Qubit Controller 8.5 GHz front panel

Table 1: SHFQC+ Qubit Controller front panel description
Position	Label / Name	Description
A	Aux In	analog Auxiliary Input, max. 10 V
B	Out	single-ended waveform Quantum Analyzer Signal Output, 0.5-8.5 GHz, max. 10 dBm
C	Mark	Quantum Analyzer TTL Marker Outputs A and B
D	Trig	Quantum Analyzer TTL Trigger Inputs A and B
E	Input Signal Over	off power of input signal within the input power range red power of input signal exceeds the input power range
F	In	single-ended waveform Quantum Analyzer Signal Input, DC-8.5 GHz, max. 10 dBm
G	Trig	Signal Generator TTL Trigger Input
H	Mark	Signal Generator TTL Marker Output
I	Out	single-ended waveform Signal Generator Signal Output, DC-8.5 GHz, max. 10 dBm
J	Aux In	analog Auxiliary Input, max. 10 V
K	Aux In Over	unused
L	Output On	off Output disabled blue Output enabled
M	multicolor LEDs	off Instrument off or uninitialized blink all LEDs blink for 5 seconds → indicator used by the Identify Device functionality
		Busy	unused
		Ext Ref	off External Reference Signal not present/detected blue External Reference Signal is present and locked on to yellow External Reference Signal present, but not locked on to red External Reference Signal present, but lock failed
		ZSync	off no connection blue steady: ZSync fully connected AND synchronized blinking: ZSync synchronized but not yet fully connected yellow ZSync plugged in, but not connected red ZSync interface error
		Status	off Instrument off or uninitialized blue Instrument is initialized and has no warnings or errors yellow Instrument has warnings red Instrument has errors
N	Soft power button	Power button with incorporated status LED off Instrument off and disconnected from mains power blue flashing rapidly (>1/sec): Firmware is starting flashing slow (<1/sec): Firmware ready, waiting for connection constant: Instrument ready and active connection over USB or Ethernet red breathing: Instrument off but connected to mains power → safe to power off using the rear panel switch, or restart using the soft power button flashing: Instrument booting up constant: Fatal error occurred

Back Panel Tour¶

The back panel is the main interface for power, control, service and connectivity to other ZI instruments. Please refer to Figure 3 and Table 2 for the detailed description of the items.

Figure 3: SHFQC+ Instrument back panel

Table 2: SHFQC+ Instrument back panel description
Position	Label / Name	Description
A	Earth ground	4 mm banana jack connector for earth ground, electrically connected to the chassis and the earth pin of the power inlet
B	AC 100 - 240 V	Power inlet, fuse holder, and power switch
C	MDS 1	Unused
D	MDS 2	Unused
E	USB 1	Universal Serial Bus (USB) 3.0 port connector for maintenance
F	LAN 1GbE	1 Gbit LAN connector for instrument control
G	DIO 32bit	32-bit digital input/output (DIO) connector
H	USB 2	Universal Serial Bus (USB) 3.0 port connector for instrument control (LabOne version ≥ 24.01)
I	ZSync Secondary	Unused Attention: This is not an Ethernet plug, connection to an Ethernet network might damage the Instrument.
J	ZSync Primary	Primary inter-instrument synchronization bus connector Attention: This is not an Ethernet plug, connection to an Ethernet network might damage the instrument.
K	External Clk In	External Reference Clock Input (10 MHz/100 MHz) for synchronization with other instruments
L	External Clk Out	External Reference Clock Output (10 MHz/100 MHz) for synchronization with other instruments

Ordering Guide¶

Table 3 provides an overview of the available SHFQC+ products and options. Upgradeable features are options that can be purchased anytime without the need to send the Instrument back to Zurich Instruments.

Table 3: SHFQC+ Instrument product codes for ordering
Product code	Product name	Description	Field upgrade possible
SHFQC2+	SHFQC+ Qubit Controller 2-Channel Configuration	Base instrument with 2 SG channels enabled	-
SHFQC4+	SHFQC+ Qubit Controller 4-Channel Configuration	Base instrument with 4 SG channels enabled	-
SHFQC6+	SHFQC+ Qubit Controller 6-Channel Configuration	Base instrument with 6 SG channels enabled	-
SHFQC-2T4	SHFQC2+ to SHFQC4+ Upgrade Option	Software Upgrades the SHFQC2+ to a SHFQC4+ or the SHFQC2 to a SHFQC4	yes
SHFQC-2T6	SHFQC2+ to SHFQC6+ Upgrade Option	Software Upgrades the SHFQC2+ to a SHFQC6+ or the SHFQC2 to a SHFQC6	yes
SHFQC-4T6	SHFQC4+ to SHFQC6+ Upgrade Option	Software Upgrades the SHFQC4+ to a SHFQC6+ or the SHFQC4 to a SHFQC6	yes
SHFQC-16W	SHFQC-16W Integration Weights Extension Option	Option for all variants of the SHFQC+ and SHFQC	yes
SHFQC-RTR	SHFQC+ Output Router and Adder Option	Option for all variants of the SHFQC+ and SHFQC	yes

Table 4: Product selector SHFQC+
Channel	Feature	SHFQC2+	SHFQC4+	SHFQC6+	SHFQCX+ + SHFQC-16W
Quantum Analyzer	Readout Channels	1
		Number of independent RF readout bands (>1 GHz)	1
		Number of integration weights	8	8	8	16
		Oscillators	2
		Mixer-calibration-free analog frequency conversion (double super-heterodyne)	yes
		Frequency range	0.5-8.5 GHz
		Total number of Markers/Triggers	2/2
		Vertical resolution Input/Output	14 bit
		Sequencing	yes
Signal Generator	Control Channels	2	4	6	X
		Number of independent RF control bands (>1 GHz)	1	2	3	see left
		Digital oscillators per channel	8
		Mixer-calibration-free analog frequency upconversion (double super-heterodyne)	yes
		Frequency range	DC-8.5 GHz
		Total number of Markers/Triggers	2/2	4/4	6/6	X/X
		Vertical resolution Output	14 bit
		Digital IQ modulation	yes
		Pulse-level Sequencing	yes
Shared resources	ZSync capability	yes
		USB 3.0	yes
		LAN 1 Gbit/s	yes

Table 5: Differences between SHFQC and SHFQC+
Category	SHFQC	SHFQC+
Description	Base instrument	Improved phase noise Improved output noise Fast output muting functionality
External differences	Base instrument	Holographic "+" sticker on front panel
Product image
Upgrading from SHFQC to SHFQC+	Contact us to discuss the possibilities for your instruments!	-