Real-time spectrum analyzers are ideal for capturing elusive signals, combining the broadband view of a spectrum analyzer with the triggering capabilities of an oscilloscope. Traditionally, though, they have been aimed at high-end users, with a price tag to match. Fortunately, Tektronix has opened the door to real-time spectrum analysis for more costconscious users, with their new RSA5000 series signal analyzers.

They provide as much as 85-MHz instantaneous capture bandwidth at frequencies to 6.2 GHz to cover a wide range of signal- analysis applications in communications, electronic warfare (EW), radar, electromagnetic-interference (EMI) troubleshooting, and spectrum management.

The RSA5000 series analyzers include the 1-Hz-to-3-GHz model RSA5103A and the 1-Hz-to-6.2-GHz model RSA5106A (Fig. 1). They can replace both a spectrum analyzer and a vector signal analyzer by performing high-speed signal processing on a captured bandwidth, either 25 MHz in standard configuration or 40 or 85 MHz bandwidth as options. The analyzers' new third generation DPX now adds the real-time signal analysis capability of 50,000 waveforms/s for Amplitude, Phase, and Frequency vs time, compared to the typical capability of about 30 to 100 amplitude- versus-time traces of a conventional spectrum analyzer which can easily miss transient events.

In zero-span mode, the DPX capability captures all events within the acquisition bandwidth; in swept mode, the acquisition bandwidth can be swept across the full bandwidth of the analyzer to capture signals over a 3- or 6-GHz range, depending upon model. the new DPX signal processing, which shows amplitude, frequency, or phase as a function of time, is ideal for analyzing rapidly changing signals, such as modulated carriers or frequencyhopping sources (Fig. 2). The analyzers are capable of measuring spectral transients as brief as 5.8 s.

As much as the RSA5000 series analyzers are signal-analysis instruments, they are also invaluable signal-capture tools, with comprehensive triggering capabilities like an oscilloscope. They can trigger on runt events, frequency, and time-qualified power. The DPX density trigger can capture any changes in the statistics of a frequency-domain signal and store anomalies. the analyzers are outfitted with 1 GB standard acquisition memory and 4 GB as an option. They can store all signals in file formats compatible with MATLAB analysis software from the MathWorks. the analyzers can also send digital in-phase/ quadrature (I/Q) outputs to external digital storage units, such as hard drives, for continuous signal capture.

The RSA5000 series analyzers both feature wide dynamic range, with a thirdorder intercept of +17 dBm and displayed average noise level (DANL) of -154 dBm at 2 GHz. With the integral preamplifier, the DANL of both analyzers can be extended to -163 dBm at 2 GHz. the phase noise is -109 dBc/Hz offset 10 kHz from a 1-GHz carrier. Standard measurements include channel power, adjacent-channel power, occupied bandwidth, and CCDF.

The RSA5000 series analyzers range from $34,900 for a model RSA5103A with 25-MHz acquisition bandwidth to $68,800 for a model RSA5106A with 85-MHz acquisition bandwidth.JB