BNC RTSA 7500 Operating and maintenance manual

RTSA 7500
Real Time Spectrum Analyzer
Programmer's Manual
Version 3.6.2
Berkeley Nucleonics Corporation, 2955 Kerner Blvd., San Rafael, CA 90901
Phone: [phone], Fax: [phone], [e-mail], www.berkeleynucleoncis.com

Important notice
The information in this
guide is furnished for
informational use only
and is subject to change
without notice. Berkeley
Nucleonics Corporation
assumes no
responsibility or liability
for any errors or
inaccuracies that may
appear in this document.
No part of this
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means, electronic,
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or otherwise, for any
purpose, without the
prior written permission
of BNC Corporation.
Trademarks
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RTSA 7500 are
trademarks of Berkeley
Nucleonics Corporation.
The following are
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trademarks of their
respective companies or
owners:
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All other brand or
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Berkeley
Nucleonics Corp
2955 Kerner Blvd.
San Rafael, CA 94901
[phone]
HARDWARE WARRANTY AND LIMITATION OF LIABILITY
Read this warranty carefully before you use the product.
RTSA7500 Real Time Spectrum Analyzers are warranted for workmanship and
materials for a period of one (1) year from the date of shipment as identified by the
Customer’s packing slip or carrier waybill. BNC reserves the right to void the
warranty on any equipment that has been altered or damaged due to Customer
negligence, unauthorized repair, misuse of equipment, evidence of physical or
environmental damage, transportation abuse or removal of any BNC identification
labels or serial numbers.
It will remain the responsibility of the Customer, having obtained a Return Material
Authorization (RMA) and shipping instructions from BNC, to return, at the
Customer's expense, the defective unit to BNC’s repair facilities. BNC will incur
shipping charges for the return of warranty repaired equipment. The RMAnumber
can be secured by calling BNC Customer Service and Support (+1.800.234.7858). If
the product does not fall within BNC’s warranty period or the product is found to be
functioning as designed, then under the terms of BNC’s warranty policy, all costs of
repairs and shipping will be charged directly to the Customer. BNC will warrant
repaired units for a period of 90 days from date of shipment from BNC to the
Customer. If the remaining period on the original hardware warranty is greater than
30 days, then BNC will honor this remaining warranty period.
BNC EXPRESSLY DISCLAIMS ALL OTHER WARRANTIES AND CONDITIONS,
WHETHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION,
WARRANTIES, CONDITIONS OR REPRESENTATIONS OF WORKMANSHIP,
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, DURABILITY, OR
THAT THE OPERATION OF THE HARDWARE OR LICENSED SOFTWARE WILL
BE ERROR FREE. IN NO EVENT WILL BNC BE LIABLE FOR INDIRECT,
SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
USE OF PRODUCTS IN HIGH RISK ACTIVITIES
BNC PRODUCTS ARE INTENDED FOR STANDARD INDOOR COMMERCIAL
USE. WITHOUT THE APPROPRIATE NETWORK DESIGN ENGINEERING, THEY
MUST NOT BE USED FOR ANY “HIGH RISK ACTIVITY”, as described in this
paragraph. Customer acknowledges and agrees that the products supplied
hereunder are not fault-tolerant and are not designed, manufactured or intended for
use or resale as on-line control equipment in hazardous environments requiring fail
safe performance including but not limited to the operation of nuclear facilities,
aircraft navigation or communication systems, air traffic control, direct life support
machines, or weapons systems, in which the failure of products could lead directly to
death, personal injury, or severe physical or environmental damage, all of which are
examples of “High Risk Activity”. BNC AND ITS SUPPLIERS EXPRESSLY
DISCLAIMANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH
RISK ACTIVITIES.
GNU General Public License
This device contains free firmware: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later version. This
program is distributed in the hope that it will be useful, but WITHOUTANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FORA PARTICULAR PURPOSE. See the GNU General Public License
for more details. GNU General Public License is available at
http://www.gnu.org/licenses.

Table of Contents
Abbreviations ..................................................................................................... 7
List of Figures ..................................................................................................... 8
List of Tables ....................................................................................................... 9
Preface ............................................................................................................. 10
Audience ........................................................................................................... 10
Conventions ..................................................................................................... 10
Obtaining Documentation and Releases ....................................................... 10
Document Feedback ........................................................................................ 11
Obtaining Technical Assistance ..................................................................... 11
RTSA 7500 Functional Overview ................................................................... 12
System Overview ............................................................................................. 12
The Architecture .............................................................................................. 15
RF Receiver Front-End .................................................................................... 17
Direct-Conversion Receiver Technology ............................................................................... 18
DC Offset Correction ....................................................................................................... 18
IQ Offset Correction ......................................................................................................... 19
Digital Signal Processing ................................................................................ 21
Digital Down Converter .......................................................................................................... 21
Triggers ............................................................................................................. 21
Frequency Domain Triggering ............................................................................................... 22
Periodic Triggering ................................................................................................................. 23
External Triggering ................................................................................................................. 23
Capture Controller ........................................................................................... 23
Trace Capture Control ........................................................................................................... 24
Sweep Capture Control ......................................................................................................... 24
Synchronized Sweep ............................................................................................................. 26
VITA-49 Radio Transport Protocol ................................................................. 28
Purpose ............................................................................................................ 28
RTSA7500's VRT Overview ............................................................................. 28
Packet Classes and Streams .......................................................................... 29
Receiver Context Packet Class ............................................................................................. 29
Context Field Change Indicator ....................................................................................... 31
Reference Point ............................................................................................................... 31
RF Reference Frequency ................................................................................................ 31
Gain ................................................................................................................................. 31
Temperature .................................................................................................................... 31
Digitizer Context Packet Class .............................................................................................. 32
Context Field Change Indicator ....................................................................................... 33
Bandwidth ........................................................................................................................ 33
Reference Level .............................................................................................................. 33

RF Frequency Offset ....................................................................................................... 34
Extension Context Packet Class ........................................................................................... 35
Context Field Change Indicator ....................................................................................... 36
IQ Swapped Indicator ...................................................................................................... 36
New Stream Start ID ........................................................................................................ 36
New Sweep Start ID ........................................................................................................ 36
IF Data Packet Class ............................................................................................................. 37
Picosecond Timestamp Words Format ........................................................................... 38
Data Payload Format ....................................................................................................... 38
Trailer Word Format ......................................................................................................... 40
SCPI Command Set ......................................................................................... 42
SCPI Language Overview ................................................................................ 42
IEEE Mandated SCPI Commands ................................................................... 43
*CLS ...................................................................................................................................... 43
*ESE/*ESE? ........................................................................................................................... 43
*ESR? .................................................................................................................................... 44
*IDN? ..................................................................................................................................... 44
*OPC/*OPC? ......................................................................................................................... 44
*RST ...................................................................................................................................... 44
*SRE/*SRE? .......................................................................................................................... 45
*STB? .................................................................................................................................... 45
*TST? ..................................................................................................................................... 45
*WAI ....................................................................................................................................... 46
SYSTem Commands ........................................................................................ 46
:SYSTem:ABORt .................................................................................................................... 46
:SYSTem:CAPability? ............................................................................................................ 46
:SYSTem:CAPTure:MODE? .................................................................................................. 46
:SYSTem:COMMunicate:LAN:APPLy .................................................................................... 47
:SYSTem:COMMunicate:LAN:CONFigure ............................................................................ 47
:SYSTem:COMMunicate:LAN:DNS ....................................................................................... 48
:SYSTem:COMMunicate:LAN:GATEway ............................................................................... 48
:SYSTem:COMMunicate:LAN:IP ........................................................................................... 48
:SYSTem:COMMunicate:LAN:NETMask ............................................................................... 49
:SYSTem:ERRor[:NEXT]? ..................................................................................................... 49
:SYSTem:ERRor:ALL? .......................................................................................................... 50
:SYSTem:FLUSh .................................................................................................................... 50
:SYSTem:LOCK:HAVE? ........................................................................................................ 51
:SYSTem:LOCK:REQuest? ................................................................................................... 51
:SYSTem:OPTions? ............................................................................................................... 52
:SYSTem:SYNC:MASTer ....................................................................................................... 52
:SYSTem:SYNC:WAIT ........................................................................................................... 53
:SYSTem:VERSion? .............................................................................................................. 53
:SYSTem:DATE ..................................................................................................................... 53
:SYSTem:TIME ...................................................................................................................... 54
:SYSTem:TIME:ADJust ......................................................................................................... 54
:SYSTem:TIME:SYNC ........................................................................................................... 54
:SYSTem:TIME:SYNC:STATus? ............................................................................................ 55
STATus Commands .......................................................................................... 56
:STATus:OPERation[:EVENt]? .............................................................................................. 57
:STATus:OPERation:CONDition? .......................................................................................... 57
:STATus:OPERation:ENABle ................................................................................................. 58
:STATus:PRESET .................................................................................................................. 58
:STATus:QUEStionable[:EVENt]? .......................................................................................... 58
:STATus:QUEStionable:CONDition? ..................................................................................... 58
:STATus:QUEStionable:ENABle ............................................................................................ 59

:STATus:TEMPerature? ......................................................................................................... 59
INPut Commands ............................................................................................. 60
:INPut:ATTenuator ................................................................................................................. 60
:INPut:ATTenuator:VARiable .................................................................................................. 60
:INPut:FILTer:PRESelect ....................................................................................................... 60
:INPut:GAIN ........................................................................................................................... 61
:INPut:GAIN:IF ....................................................................................................................... 61
:INPut:GAIN:HDR .................................................................................................................. 62
:INPut:MODE ......................................................................................................................... 62
SOURce Commands ........................................................................................ 63
:SOURce:REFerence:PLL ..................................................................................................... 63
:SOURce:REFerence:PLL:RESET ........................................................................................ 63
SENSe Commands ........................................................................................... 64
[:SENSe]:CORRection:DCOFfset .......................................................................................... 64
[:SENSe]:DECimation ............................................................................................................ 64
[:SENSe]:FREQuency:CENTer .............................................................................................. 65
[:SENSe]:FREQuency:IF? ..................................................................................................... 66
[:SENSe]:FREQuency:LOSCillator? ...................................................................................... 66
[:SENSe]:FREQuency:SHIFt ................................................................................................. 67
[:SENSe]:FREQuency:RESolution? ...................................................................................... 67
[:SENSe]:LOCK:REFerence? ................................................................................................ 67
[:SENSe]:LOCK:RF? ............................................................................................................. 68
OUTput Commands ......................................................................................... 68
:OUTput:IQ:MODE ................................................................................................................. 68
:OUTput:IQ:CONNector:INVersion? ...................................................................................... 69
TRIGger Commands ........................................................................................ 69
:TRIGger:TYPE ...................................................................................................................... 69
:TRIGger:LEVel ...................................................................................................................... 70
:TRIGger:PERiodic ................................................................................................................ 70
:TRIGger:STATus? ................................................................................................................. 70
TRACe Commands .......................................................................................... 71
:TRACe:BLOCk:DATA? ......................................................................................................... 71
:TRACe:BLOCk:PACKets ...................................................................................................... 72
:TRACe:SPPacket ................................................................................................................. 73
:TRACe:STReam:STARt ....................................................................................................... 73
:TRACe:STReam:STOP ........................................................................................................ 74
SWEep Commands .......................................................................................... 74
:SWEep:LIST:ITERations ...................................................................................................... 75
:SWEep:LIST:STARt .............................................................................................................. 76
:SWEep:LIST:STATus? .......................................................................................................... 76
:SWEep:LIST:STOP ............................................................................................................... 77
:SWEep:ENTRy:COPY .......................................................................................................... 77
:SWEep:ENTRy:COUNt? ...................................................................................................... 77
:SWEep:ENTRy:DELETE ...................................................................................................... 78
:SWEep:ENTRy:NEW ............................................................................................................ 78
:SWEep:ENTRy:READ? ........................................................................................................ 78
:SWEep:ENTRy:SAVE ........................................................................................................... 78
:SWEep:ENTRy:ATTenuator .................................................................................................. 79
:SWEep:ENTRy:DECimation ................................................................................................. 79
:SWEep:ENTRy:FILTer:PRESelect ....................................................................................... 79
:SWEep:ENTRy:FREQuency:CENTer ................................................................................... 79
:SWEep:ENTRy:FREQuency:STEP ...................................................................................... 80
:SWEep:ENTRy:FREQuency:SHIFt ...................................................................................... 80
:SWEep:ENTRy:GAIN:HDR .................................................................................................. 80

:SWEep:ENTRy:GAIN:IF ....................................................................................................... 81
:SWEep:ENTRy:MODE ......................................................................................................... 81
:SWEep:ENTRy:DWELl ......................................................................................................... 81
:SWEep:ENTRy:PPBlock ...................................................................................................... 81
:SWEep:ENTRy:SPPacket .................................................................................................... 82
:SWEep:ENTRy:TRIGger:LEVel ............................................................................................ 82
:SWEep:ENTRy:TRIGger:TYPE ............................................................................................ 82
Appendix A: Connecting to RTSA 7500 ....................................................... 82
Appendix B: Protocol for Discovering RTSA 7500 ..................................... 84
Appendix C: SCPI Command Syntax ........................................................... 85
Entering Commands ........................................................................................ 85
Notation ............................................................................................................ 86
Parameter types ............................................................................................... 86
Default Units ..................................................................................................... 87
Appendix D: SCPI Status and Event Registers ........................................... 88
Status Byte Register (SBR) ............................................................................. 88
Standard Event Status Register (ESR) ........................................................... 88
Operational Status (OSR) Register ................................................................. 89
Output Queue ................................................................................................... 89
Error and Event Queue .................................................................................... 89
Appendix E: SCPI Error Codes Used ........................................................... 90
Appendix F: SCPI Commands Quick Reference ......................................... 91
References ....................................................................................................... 97
Document Revision History ........................................................................... 98

Abbreviations
ADC
Analog-to-Digital Converter
API
Application Programming Interface
CIC
Cascaded Integrator-Comb
DC
Direct Current
DD
Direct Digitizer
DDC
Digital Down Converter
DDS
Direct Digital Synthesizer
DSP
Digital Signal Processing
ELO
External Local Oscillator
FFT
Fast Fourier Transform
FIR
Finite Impulse Response
FPGA
Field-Programmable Gate Array
GPIO
General Purpose Input/Output
HDR
High Dynamic Range
HIF
High Intermediate Frequency
IBW
Instantaneous Bandwidth
IEEE
Institute of Electrical and Electronics Engineers
IF
Intermediate Frequency
IQ
In-phase and Quadrature
IQIN
External I and Q Input
LAN
Local Area Network
MB
Mega-Bytes
MSB
Most Significant Byte
NB
Narrowband
NCO
Numerically Controlled Oscillator
PLL
Phase-Locked Loop
RF
Radio Frequency
RFE
Receiver Front-End
Sa/s
Samples-per-Second
SCPI
Standard Commands for Programmable Instruments
SH
Super-Heterodyne
SHN
Super-Heterodyne with narrower bandwidth
TCP/IP
Transmission Control Protocol/Internet Protocol
TD
Time Domain
TSF
TimeStamp-Fractional
TSI
TimeStamp-Integer
TSM
TimeStamp Mode
UTC
Coordinated Universal Time
VCO
Voltage Control Oscillator
VRT
VITA-49 Radio Transport
WB
Wideband
RTSA
Real Time Spectrum Analyzer
ZIF
Zero Intermediate Frequency

List of Figures
Figure 1: RTSA 7500 Functional Block Diagram ..................................................................................... 13
Figure 2: RF Receiver Front-end and Capture Controller Functional Block Diagram ............................. 16
Figure 3: DC Offset with Amplitude Roll-Off at +50MHz .......................................................................... 18
Figure 4: IQ Offset Correction .................................................................................................................. 20
Figure 5: DDC Functional Block Diagram ................................................................................................ 21
Figure 6: Association between Time and Frequency Domain .................................................................. 22
Figure 7: Synchronized Sweep using Sync-Word .................................................................................... 27
Figure 8: Synchronized Sweep with a Missed Capture ........................................................................... 27
Figure 9: Connectivity and 4 Different Packet Streams Supported by RTSA 7500 ................................. 28
Figure 10: An Example Illustrating Uninverted and Inverted Spectrums ................................................. 41
Figure 11: SCPI Language Hierarchical or Tree Structure Example ....................................................... 42
Figure 12: SCPI Measurement Function Block ........................................................................................ 43
Figure 13: Status Reporting Structure with Status & Enable Registers ................................................... 56

List of Tables
Table 1: System Level Control/Status Commands .................................................................................. 14
Table 2: Radio RFE Modes and DSP Data Output Formats .................................................................... 17
Table 3: RF Front-End Control/Status Commands .................................................................................. 20
Table 4: Trigger Control/Status Commands ............................................................................................. 23
Table 5: Trace Capture Control Commands ............................................................................................. 24
Table 6: Sweep Capture Control/Status Interface .................................................................................... 25
Table 7: The Categories of VRT Packet Streams Supported by Berkeley Nucleonics's RTSA 7500 ...... 28
Table 8: A List of Stream Identifiers As Used by Berkeley Nucleonics for Different Packet Classes ....... 29
Table 9: Receiver Context Packet Class Structure .................................................................................. 30
Table 10: Receiver Context Indicator Field Positions .............................................................................. 30
Table 11: Receiver Context Field Definition and Values .......................................................................... 30
Table 12: RF Reference Frequency Word Format ................................................................................... 31
Table 13: Gain Field Format ..................................................................................................................... 31
Table 14: Temperature Field Format ........................................................................................................ 32
Table 15: Digitizer Context Packet Class Structure ................................................................................. 32
Table 16: Digitizer Context Indicator Field Bit Positions .......................................................................... 33
Table 17: Digitizer Context Field Values .................................................................................................. 33
Table 18: Bandwidth Word Format ........................................................................................................... 33
Table 19: Reference Level Field Format .................................................................................................. 34
Table 20: RF Frequency Offset Word Format .......................................................................................... 35
Table 21: Extension Context Packet Class Structure .............................................................................. 35
Table 22: Extension Context Indicator Field Positions ............................................................................. 35
Table 23: Receiver Context Field Definition and Values .......................................................................... 36
Table 24: New Stream Start ID Field Format ........................................................................................... 36
Table 25: New Sweep Start ID Field Format ............................................................................................ 37
Table 26: Output Data Width and Packing Method for Different Data Formats ....................................... 37
Table 27: IF Data Class Field Values ....................................................................................................... 37
Table 28: Stream Identifier Values for Different Data Output Formats ..................................................... 38
Table 29: 64-bit or Two Words Picosecond Timestamp Format ............................................................... 38
Table 30: {I14Q14} Data Payload Arrangement with Upper 2-bit of Each Item Signed Extended to {I16
Q16} ......................................................................................................................................... 39
Table 31: {I14} Data Payload Arrangement with Upper 2-bit Signed Extended to {I16} .......................... 39
Table 32: {I24} Data Payload Arrangement with Upper 8-bit Signed Extended to {I32} .......................... 39
Table 33: Trailer Word Format .................................................................................................................. 40
Table 34: Trailer Indicator and Enable Bits .............................................................................................. 40
Table 35: Conditions Causing Abnormal Indicator State and Suggested Resolution .............................. 41
Table 36: RTSA 7500 Option Codes and the Corresponding Description ............................................... 52
Table 37: Max, Min, and Required Multiples for SPP and Samples-per-word for Different Data Output
Format ..................................................................................................................................... 73

Preface
This preface describes the audience for, the organization of, and conventions used in this
document. It also identifies related documentation and explains how to access electronic
documentation.
Audience
This document is written for software developers wishing to develop and/or maintain a
software interface to the RTSA7500 and who have a basic understanding, familiarity and
experience with network test and measurement equipment.
Conventions
This section describes the conventions used in this document.
Grayed-out Font
Indicates a command or a feature is not yet available in the current release.
Courier Font
Illustrates this is an example for a command or a concept.
Light Blue Font
Contains hyperlink to the referenced source that can be clicked on.
Normal Bold Font
When used within a sentence or a paragraph, it emphasizes an idea to be paid attention
to particularly.
Red Font
Conveys special information of that section.
Note: This symbol means take note. Notes contain helpful suggestions or references to
additional information and material.
Caution: This symbol means be careful. In this situation, you might do something that
could result in equipment damage or loss of data.
Warning: This symbol means danger. You are in a situation that could cause bodily
injury. Before you work on any equipment, be aware of the hazards involved with
electrical circuitry and be familiar with the standard practices for preventing accidents.
Obtaining Documentation and Releases
You can access the most current BNC documentation at relsease bundles at
http://www.berkeleynucleonics.com/support/model-7500-support-resources.

Document Feedback
Please send your comments about this document or our other documentation to
[e-mail].
Thank you, we appreciate your comments.
Obtaining Technical Assistance
The BNC Support website provides online documents for resolving technical issues with
BNC products at this URL: http://www.berkeleynucleonics.com/model-7500
For all customers who hold a valid end-user license, BNC provides technical assistance 9
AM to 5 PM Eastern Time, Monday to Friday. Contact us at
[e-mail] or by calling +1.415.453.9955 or
+1.800.234.7858.
Before contacting Support, please have the following information available:
RTSA7500's serial number. The serial number S/N is located on the identification
label on the RTSA7500's underside;
version of BNC firmware you are using, potentially including version of GUI
and/or API libraries to third-party applications; and
the operating system you are using.

VITA-49 Radio Transport Protocol
BNC RTSA7500 Real Time Spectrum Analyzer Programmer's Guide 12
RTSA7500 Functional Overview
This section overviews the RTSA7500's functionality and protocols used, and
summarizes the SCPI command sets for controlling the individual functions.
Note: This is a living and evolving document. We welcome your feedback.
The features and functionality described in this section may exist in the current product
firmware release or are scheduled for a future product firmware release (grayed out
commands and/or text). Please refer to Appendix F: SCPI Commands Quick Reference
for the complete list of commands and the availability information. No hardware upgrade
is required at each feature release (unless specified though unlikely).
System Overview
The Model 7500 Real Time Spectrum Analyzer is a high-performance software-defined
RF receiver, digitizer and analyzer, as illustrated in Figure 1. With patent-pending
software-defined RF receiver technology, the RSTA 7500 provides industry leading
combined sensitivity, tuning range, instantaneous bandwidth (IBW) and scan rate.
Additionally, it provides real-time sophisticated triggering and capture control.
The Model 7500 is designed for stand-alone, remote and/or distributed wireless signal
analysis. It is ideal for monitoring, management and surveillance of transmitters, whether
they are in-building or spread across a geographic area. Applications include, but are not
limited to:
spectrum analysis, wireless network management and interference mitigation;
cognitive radio and white space spectrum sensing, enterprise wireless signal
intrusion detection (WSID);
government spectrum licensing monitoring and enforcement;
technical security counter measures (TSCM) and military communications and
signals intelligence (COMINT/SIGINT and CEW).
The RSTA 7500 hardware largely consists of:
a hybrid super-heterodyne and direct-conversion RF receiver front-end (RFE);
receiver front end inputs and outputs to support clock synchronization, direct
digitization input, and IF output for high-end digitization;
a 125 MSample/sec 12-bit (or 14-bit as a population variant) wideband (WB)
ADC with a dynamic range of about 70dB;
a 300 kSample/sec 24-bit narrowband (NB) ADC with a dynamic range in excess
of 100dB;
a large Xilinx FPGA with embedded MicroBlaze microprocessor, Gigabit Ethernet
interface and custom embedded digital signal processing (DSP) logic;
128 or 256 MB of DDR3 for real-time caching of digitized data; and
a general purpose input/output (GPIO) port.

Figure 1: RTSA7500 Functional Block Diagram
BNC's products conform with standardized protocols for interoperability. BNC provides
application programming interfaces (APIs) designed for easy integration with third-party
applications. Standard protocols include the Standard Commands for Programmable
Instruments (SCPI) protocol for controlling and obtaining status from the 7500 and the
VITA-49 Radio Transport (VRT) protocol for digitized data and its associated context
information.
In addition, API libraries, written in C/C++, Python and MATLAB, are provided for quick
interfacing, data acquisition and as well as for spectral analysis with MATLAB®
applications. The Python API is open-source under BSD licensing. Python API handles
the low-level details of real-time acquisition, signal processing and visualization, and
provides feature rich libraries, example applications and source code, all specific to the
requirements of signal analysis. Usage examples are provided through the available
source codes of the Graphical User Interfaces (GUI) or any applications included in each
release package.
Refer to Appendix A for how to connect to a RTSA 7500 and Appendix B for the protocol
on how to find any 7500's available on the local network. The source code provided for
the aforementioned APIs and GUIs/applications would serve as examples.
The RTSA7500 provides system level control and status commands as defined in Table
1.

Table 1: System Level Control/Status Commands
SCPI Command
Description
:SYSTem
Page 46
:ABORt
Aborts the current data capturing process and puts thesystem into a
normal manual mode (i.e. sweep, trigger, and streaming will be aborted)
:CAPability?
Returns a list of the RTSA7500's capabilities including firmware versions
and installed hardware options
:CAPTure
:MODE?
Gets the current capture mode of the RTSA 7500 (i.e. sweeping,
streaming or block mode)
:COMMunicate
:LAN<commands>
Subset of commands for configuring/querying RTSA 7500's LAN settings
:ERRor
Returns the error code and messages from the SCPI error/event queue
[:NEXT]?
:ALL?
:FLUSh
Clears the RTS A7500's internal data storage buffer of any remaining data
that has not transferred out of the RTSA7500
:LOCK
:HAVE?
Returns the current lock state of the task specified
:REQuest?
Requests the RTSA7500 to provide a lock on a specific task such that
only the application that has the lock can perform the task
:OPTions?
Returns comma separated 3-digit values to represent the hardware
option(s) or features available with a particular RTSA 7500 model
:SYNC
:MASTer[?]
Sets a RTSA7500 unit to be the master or slave for a synchronization
trigger system with multiple units. Affects :TRIGger:TYPE PULSe or
WORD.
:WAIT[?]
Sets the delay time in nanoseconds that the system must wait after
receiving the trigger signal before performing data capture
:VERSion?
Returns the SCPI version number that the instrument complies with
:DATE[?]
Sets/reads date
:TIME[?]
Sets/reads time
:ADJust
Adjust the system time relative to it's current time
:MODE[?]
Synchronize one time only or continuously
:SYNC[?]
Sets/ gets the System time synchronization source via network or SCPI,
or disable
:STATus?
Status of the time synchronization
:STATus
Page 56
:OPERation
Returns the standard Operation Status Register (OSR) for any event
[:EVENt]?
:CONDition?
:ENABle[?]
:PRESET
Presets the RTSA7500 (similar to *RST)
:QUEStionable
Returns the standard Questionable Status Register (QSR) for any event
[:EVENt]?

SCPI Command
Description
:CONDition?
:ENABle[?]
:TEMPerature?
Returns the RTSA7500's internal ambient temperature
See SCPI Command Set section (page 42 onward) for further details on the commands.
Caution pertaining to multi-user: The current firmware version of the RTSA7500
allows multiple applications to connect to the unit simultaneously but it does not support
independent sessions. Therefore, the actions of one user may over-write those of
another. This could potentially damage the unit for instance if the front-end's gain were
incorrectly set. If multiple applications are connecting to the unit, it is advised that only
one of those is controlling the unit at any time.
The Architecture
The RTSA7500 is an integrated wireless radio receiver and digitizer/analyzer. It has an
embedded capture controller that enables users to:
define and execute real-time and sophisticated triggers, traces and sweeps;
configure the radio RFE and DSP in association with those traces or sweeps;
and
time-stamping and data output for captures.
Traces and sweeps are controlled by the capture controller as illustrated in the lower
portion of Figure 2. A trace and a sweep are defined as a single (block or continuously
streamed) capture and a series of captures, respectively, each with their associated
hardware configurations.

Figure 2: RF Receiver Front-end and Capture Controller Functional Block Diagram
The RTSA7500 supports different RFE modes of operation and subsequent DSP
capabilities as per Table 2 and as described in the following subsections.
Table 2: Radio RFE Modes and DSP Data Output Formats
Mode0
Description
Freq Range
(MHz)
IBW
(MHz)
DSP Data Output Format1
None
CIC/Dec
Frequency Shift
ZIF
Zero-IF Receiver
50 - max
100
I14 Q14
I14 Q14
I14 Q14
SH
Super-Heterodyne
Receiver
50 - max
402
I14
I14 Q144
I14 Q14
SHN3
SH Receiver with
narrower BW
50 - max
10
I14
I14 Q144
I14 Q14
HDR
High Dynamic Range
Receiver
50 - max
0.1
I24
-
-
DD
Direct Digitization
Receiver
0.1 - 506
50
I14
I14
I14 Q14
IQIN5
External IQ Input
0.1 - 506
100
I14 Q14
I14 Q14
I14 Q14
HIF7
High IF Receiver
50 - max
--
–
–
–
0The RFE Mode availability is product dependent.

1The RTSA7500 supports a 12-bit or 14-bit WB ADC as a manufacturing population variant. The
least significant bits of the 14-bit data representations are zeroed when the RTSA7500 is
populated with the 12-bit WB ADC, hence, the subscript of 14 for IQ or I.
2The 40MHz SH is only available in RTSA7500 product version 1.3 (hardware revision 3) and
higher. Revision 2 hardware value varies between 30 or 35MHz, contact BNC's Support for further
details. See *IDN? to find out your hardware/product version (or the Administrative web-console to
the box).
3SHN mode is only available in RTSA7500 product version 1.3 (hardware revision 3) and higher
See *IDN? to find out your hardware/product version (or the Administrative web-console to the
box).
4For SH and SHN modes, when the decimation is used, a frequency shift of 35MHz for non-WBIQ
models and 55MHz for WBIQ models will be applied automatically to bring the RTSA7500's center
frequency back to the zero IF. Thus, the data output will be I and Q.
5IQIN mode is not available in RTSA 7500 product version 2.2 and higher. See *IDN? to find out
your product version (or the Administrative web-console to the box).
6In DD and IQIN modes, there is no frequency tuning except for performing frequency shift. When
decimation is applied, the decimation will be around the zero frequency.
7The HIF mode is only available for RTSA7500-XXX-HIF product model and is indicated by the
:SYSTem:OPTions? command's response code 002.
RTSA7500 complies to VRT protocol for sending digitized IF data packets and their
associated context information depending on the capture mode. It is very important to
follow the VRT's IF Data Packet Class section (page 36) for the exact VRT data output
formats as well as packing method.
RF Receiver Front-End
The upper portion of Figure 2 shows a block diagram of the RFE within the RTSA 7500.
The architecture consists of a super-heterodyne (SH) front-end with a back-end that
utilizes an I/Q mixer similar to that in a direct-conversion (or zero-IF) receiver.
Depending on the frequency of the signals being analyzed, one of the three receiver
signal processing paths is selected. Signals in the frequency range 100kHz to 50MHz
are directly digitized, while all other signals are translated to the frequencies of the first IF
block via one of the other two signal processing paths. The IF block consists of a bank of
multiple SAW filters. SAW filter selection depends on the frequency of the input signal.
The output of the SAW filter feeds the I/Q mixer.
The three signal processing paths are further classified into different modes of operation
for the capture engine as shown in Table 2. The radio modes ZIF, SH, SHN and HDR
support tuning the center frequency from 50MHz to the maximum frequency supported by
the particular product model (ex. 8GHz, 18GHz, 20GHz, and 27GHz for RTSA7500-08,
RTSA7500-18, RTSA7500-20, and RTSA7500-27, respectively).
The ZIF, SH and SHN radio modes support a tuning resolution of 10Hz. Digital frequency
shifting can then be used to enhance the tuning resolution to the nearest 1Hz (±0.23Hz)
The frequency shifting technology used is an embedded Numerically Controlled Oscillator
(NCO) (a Direct Digital Synthesizer or DDS) as described in the Digital Down Converter
subsection (page 20).
The HDR radio mode supports a tuning resolution of 10Hz. No further fine tuning is
available.
The remaining two radio modes, DD and IQIN, support 50MHz IBW direct digitization of
the baseband from the external RF IN or I and Q IN ports, respectively. Hence, neither

of these modes support frequency tuning of the radio although the DSP's frequency shift
mode may be applied.
Direct-Conversion Receiver Technology
Direct-conversion (or ZIF) receivers are ideal for signal analysis of wideband waveforms,
such as 4G/LTE, Wi-Fi and Bluetooth. With that benefit comes the drawback of both IQ
and DC offsets which are inherent to direct-conversion technology.
DC Offset Correction
The RTSA7500's WB ADC sampling rate is 125 MSa/s, intermediate frequency (IF) is 0
and the entire IF bandwidth is 125MHz. The analog filter results in an amplitude roll-off at
approximately +50MHz around the center frequency Fc, as illustrated in Figure 3.
Direct-conversion receivers have a DC offset at the center of the band. The offset is
primarily compensated for in real-time in the receiver hardware but there always is some
residual offset that (depending on the application and bandwidth of interest) might need
to be compensated for in software. Several options such as calibration or dynamic offset
compensation in software have been described in the open literature.
Figure 3: DC Offset with Amplitude Roll-Off at +50MHz
If the application only needs to utilize up to 50MHz of IBW, a simple alternative to DC
offset compensation is to use the SH mode of operation.
IQ Offset Correction
Direct-conversion receivers have phase and/or amplitude offsets between in-phase (I)
and quadrature (Q) components of the baseband signal. Due to this, when an FFT is
performed on digitized baseband data where there is a signal tone present, there will be
an ‘image’ at the same frequency offset from the center frequency as the tone itself. This
is illustrated in Figure 4.
To compensate for this, the raw I and Q data must be processed according to the
following “calibrateIQ” routine, illustrated using the following MATLAB® code. When an
FFT is performed on the output of calibrateIQ, the image will disappear. This process has
no impact on the accuracy or precision of the data.
%%%%%
% MATLAB code for IQ Offset Correction
%%%%%
function [calibratedQ] = calibrateIQ(iData, qData)
numberOfSamples = size(iData, 1);

sumOfSquaresI = sum(iData.^2);
sumOfSquaresQ = sum(qData.^2);
amplitude = sqrt(sumOfSquaresI * 2 /
numberOfSamples);
ratio = sqrt(sumOfSquaresI / sumOfSquaresQ);
p = (qData/amplitude) * ratio .* (iData/amplitude);
sinphi = 2 * sum(p) / numberOfSamples;
phi_est = -asin(sinphi);
calibratedQ =((sin(phi_est) *iData) +(ratio *qData))
/cos(phi_est);
end
Figure 4: IQ Offset Correction
Table 3: RF Front-End Control/Status Commands
SCPI Command
Description
:INPut
Page 59
:ATTenuator[?]
Enables/disables the front-end's 20dB attenuation (on some models)
:VARiable[?]
Sets the variable attenuation for RTSA7500-418 and -427
:FILTer
:PRESelect[?]
Enables/disables the use of preselect filtering
:GAIN
:IF[?]
Sets the variable IF gain
:HDR[?]
Sets gain level for the NB ADC of of the HDR signal path
:MODE[?]
Selects the receiver mode of operation
:SOURce
Page 63
:CLOCk
:ADC[?]
Selects variable or fix input clock type to the WB ADC
:RATE[?]
Sets the clock rate for the WBADC

SCPI Command
Description
:REFerence
:PLL[?]
Selects the 10MHz reference clock source
:RESET
Resets the 10MHz reference selection to INTernal source
[:SENSe]
Page 63
:CORRection
:DCOFfset[?]
Enables/disables the ADC's DC-offset correction system
:DECimation[?]
Sets the decimation rate as an exponent of 2 (i.e. rate = 2level where level =
0, 1, 2 - 10)
:FREQuency
:CENTer[?]
Sets the center frequency of the RFE
:IF?
Queries the IF frequencies that are used for the current input mode and
center frequency
:INVersion?
Queries if a spectral inversion is required at a given frequency
:LOSCillator?
Gets the frequency to be set for the external LO 1 or 2 in corresponding to
current the RTSA 7500's center frequency
:RESolution?
Gets the Analog PLL tuning resolution
:SHIFt[?]
Sets the frequency shift value (not available for HDR mode)
:LOCK
:REFerence?
Queries the lock status of the PLL reference clock
:RF?
Queries the lock status of the RFE's PLL
:OUTput
Page 67
:IQ
:MODE[?}
Selects the IQ output path to be from the external connector or the
digitizer
See SCPI Command Set section (page 42 onward) for further details on each set of
commands.
Digital Signal Processing
The RTSA7500 has embedded DSP blocks to provide further signal processing
capabilities, such DDC with up to 10 levels of decimation, and FFT computation.
Digital Down Converter
The DDC block takes the frequency band of interest and shifts it down in frequency, then
provides decimation of the sampling rate to one that is lower and consistent with the
bandwidth of the signal of interest. This enables channelization of signals having
bandwidth smaller than the IBW.
Referring to Figure 5, the DDC has two major elements, an NCO (DDS) and a down
sampling with filtering. The NCO generates a complex sinusoid, which is mixed with the
IQ input using a complex multiplier, to shift or offset the signal spectrum from the selected
carrier frequency. This process provides the frequency fine-tuning (and shifting) feature
as mentioned in the previous subsections.