Signal Hound BB60A Programmer's Reference Manual

Signal Hound | Modes of Operation
9
Determining the frequency of any point returned is determined by the function where ‘n’ is a zero based
sample point.
𝐹𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 𝑜𝑓 𝑛
′
𝑡ℎ 𝑠𝑎𝑚𝑝𝑙𝑒 𝑝𝑜𝑖𝑛𝑡 𝑖𝑛 𝑟𝑒𝑡𝑢𝑟𝑛𝑒𝑑 𝑠𝑤𝑒𝑒𝑝 = 𝑠𝑡𝑎𝑟𝑡𝐹𝑟𝑒𝑞 + 𝑛 ∗ 𝑏𝑖𝑛𝑆𝑖𝑧𝑒
Real-Time Analysis
The API provides the functionality of an online real-time spectrum analyzer for the full instantaneous
bandwidth of the device (20MHz for the BB60A, 27MHz for the BB60C). Through the use of FFTs at an
overlapping rate of 50%, the spectrum results have no blind time (100% probability of intercept) for
events as short as 50ns. Due to the demands in processing, restrictions are placed on resolution
bandwidth. Video bandwidth is non-configurable.
The configuration routines which affect the spectrum results are
 bbConfigureAcquisition() – Configure detector and linear/logarithmic scale
 bbConfigureCenterSpan() – Configure center frequency and span of no more than
the devices maximum instantaneous bandwidth, specified in the header macros.
 bbConfigureLevel() – Configure reference level and attenuators
 bbConfigureGain() – Specify internal amplifiers
 bbConfigureSweepCoupling() – Specify RBW
 bbConfigureRealTime() – Specify the real-time update rate and frame scale
The number of sweep results far exceeds a program’s capability to acquire, view, and process, therefore
the API combines sweeps results for a user specified amount of time. It does this in two ways. One, is
the API either max holds or averages the sweep results into a standard sweep. Also the API creates an
image frame which acts as a density map for every sweep result processed during a period of time. Both
the sweep and density map are returned at rate specified by the function bbConfigureRealTime. For a
full example of using real-time see Appendix: Code Examples: Real-Time Mode.
I/Q Streaming
The API is capable of providing programmers with a continuous stream of digital I/Q samples from the
device. The digital I/Q stream consists of interleaved 32-bit floating point I/Q pairs scaled to mV. The
digital samples are amplitude corrected providing accurate measurements. The I/Q data rate at its
highest is 40MS/s and can be decimated down by a factor of up to 128 (in powers of two). Each
decimation value further reduces the overall bandwidth of the I/Q samples, so the API also provides a
configurable band pass filter to control the overall passband of a given I/Q data stream. The I/Q data
stream can also be tuned to an arbitrary frequency value.
Configuration routines used to prepare streaming are
 bbConfigureCenterSpan() – Set the center frequency of the I/Q data stream.
 bbConfigureLevel() – See Gain and Attenuation in the Streaming Mode
 bbConfigureGain() – See Gain and Attenuation in the Streaming Mode
bbConfigureIO() – Configure the BNC ports of the BB60.
 bbConfigureIQ() – Specify the decimation and bandwidth of the I/Q data stream.
Once configured, initialize the device with the BB_STREAMING mode and the BB_STREAM_IQ flag. Data
acquisition begins immediately. The API buffers ~3/4 second worth of digital samples in circular buffers.
It is the responsibility of the user application to poll the samples via bbFetchRaw() fast enough to

Signal Hound BB60A Specifications

General

Brand	Signal Hound
Model	BB60A
Category	Measuring Instruments
Language	English