Functional Overview

This chapter provides the overview of the features provided by the SHFQA Instrument. Unless explicitly stated otherwise, all contents of the manual apply to both the original SHFQA as well as the SHFQA+. 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 SHFQA+ Instrument consists of several internal units that process digital data (light blue color) and several interface units processing analog signals (dark blue color). The front panel is depicted on the left-hand side and the back panel is depicted on the right-hand side. The arrows between the panels and the interface units indicate selected physical connections and the data flow. Information indicated in orange is linked to options that can be either ordered at purchase or upgraded later. The SHFQA+ Quantum Analyzer 8.5 GHz comes in a 2-channel and a 4-channel variant, providing either 2 or 4 readout channels, respectively. The Ordering Guide details the available upgrade options for each Instrument type and whether the option can be upgraded directly in the field.

Figure 1: SHFQA+ Instrument functional diagram

Each channel has signal generation (Readout Pulse Generator, Oscillator) and signal analysis (Sweeper, Qubit Measurement Unit) functionality, as well as common shared modules such as the 4-channel Monitor Scope, the Hardware Trigger Engine or shared communications (32-bit DIO, ZSync). The digital, complex-valued signal from the signal generation is up-converted to microwave frequencies in the analog domain using the Signal Output Module. After passing through the device under test, the analog signal is first down-converted and then digitized in the Signal Input Unit before the complex-valued signal is being analyzed.

The SHFQA+ can be configured in two modes:

Readout

In the 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. 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 other Instruments in real time using either the 32-bit DIO or the ZSync links.

Spectroscopy

In the Spectroscopy mode, the Sweeper (Python API ShfSweeper class) controls an Oscillator, hence a single frequency microwave signal is sent to the experiment. The Qubit Measurement Unit then correlates this signal to 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 with 1 GHz bandwidth when using the RF path, DC - 800 MHz when using the LF path
• Broadband double superheterodyne frequency down-conversion, mixer calibration free
• 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 superheterodyne frequency up-conversion, mixer calibration free
• 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 generation
• Up to 16 waveform memory blocks with 4 kSa (total 64 kSa) memory per channel, freely configurable
• Advanced sequencing including looping and branching

Qubit Measurement Unit

• Up to 16 complex integrators with programmable Integration Weight (for SHFQA2, SHFQA-16W option is required)
• Weighted integration and state discrimination
• Result Logger with real-time averaging and data logging
• Power spectral density

Scope

• 1 Scope channel per Channel
• Time and frequency domain data monitoring
• Hardware averaging and segment measurement

Hardware Trigger Engine

• Multiple choices of internal triggers
• Route internal and external triggers for different toolsets

Connectivity

• USB 3.0 high-speed host interface
• Maintenance USB connection
• LAN/Ethernet 1 Gbit/s connection
• 32-bit Digital Input and Output (DIO) port
• ZSync connection for clock synchronization and fast data transfer

Software

• 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, QCoDeS and Labber
• 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: SHFQA+ Quantum Analyzer 8.5 GHz front panel

Table 1: SHFQA+ Quantum Analyzer front panel description

Position	Label / Name	Description
A	Aux In	analog Auxiliary Input, max. 10 V
B	Out	single-ended waveform Signal Output, DC-8.5 GHz, max. 10 dBm
C	Mark	TTL Marker Outputs A and B
D	Trig	TTL Trigger Inputs A and B
E	In	single-ended waveform Signal Input, DC-8.5 GHz, max. 10 dBm
F	Aux In Over	unused
G	Output On	off Output disabled blue Output enabled
H	Input Signal Over	off power of input signal within the input power range red power of input signal exceeds the input power range
I	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
J	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 Zurich Instruments' Instruments. Please refer to Figure 3 and Table 2 for the detailed description of the items.

Figure 3: SHFQA+ Instrument back panel

Table 2: SHFQA+ 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 SHFQA+ products. Upgradeable features are options that can be purchased anytime without the need to send the Instrument back to Zurich Instruments.

Table 3: SHFQA+ Instrument product codes for ordering

Product code	Product name	Description	Field upgrade possible
SHFQA2+	SHFQA2+ Quantum Analyzer	Base 2-channel Super-High-Frequency Quantum Analyzer	-
SHFQA-16W	SHFQA-16W Integration Weights Extension Option	Option for SHFQA2+ and SHFQA2	yes
SHFQA4+	SHFQA4+ Quantum Analyzer	Base 4-channel Super-High-Frequency Quantum Analyzer	-

Table 4: Product selector SHFQA+

Feature	SHFQA2+	SHFQA2+ + SHFQA-16W	SHFQA4+
Number of Readout Channels (Readout Channel = Readout Pulse Generator + Qubit Measurement Unit)	2			4
Number of integration weights per channel	8	16
Number of integration weights total	16	32	64
Oscillators	2			4
Number of Scope Channels	2			4
Mixer-calibration-free analog frequency conversion (double super-heterodyne)	yes
Frequency range	DC-8.5 GHz
Total number of Markers/Triggers (2 each per channel)	4/4			8/8
Vertical resolution Input/Output	14 bit
Digital IQ modulation	yes
ZSync capability	yes
Sequencing	yes
USB 3.0	yes
LAN 1 Gbit/s	yes

Table 5: Differences between SHFQA and SHFQA+

Category	SHFQA	SHFQA+
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 SHFQA to SHFQA+	Contact us to discuss the possibilities for your instruments!	-