Radar component and system testing usually evokes images of complex, expensive measurement systems occupying multiple equipment racks. In some cases, radar equipment designers have even used entire radar systems as a proving ground for their new components and modules. With the introduction of the PN9002 pulse-to-pulse radar stability test set from Aeroflex, Inc. (Plainview, NY), radar testing has become significantly less complex and costly. The modular PN9002 system provides outstanding dynamic range at frequencies from 2 to 18 GHz and optionally from 0.4 to 18 GHz.
The two-rack PN9002 replaces "homegrown" radar measurement systems often costing as much as $1 million. Instead, the PN9002 is a fully self-contained, cost-effective system housed in two compact VXI racks (see figure). The system delivers precise pulsed signals to a unit under test (UUT) and then digitizes and analyzes the effect of the UUT on the test pulses. The PN9002 produces pulses at a maximum level of +13 dBm (with ±2-dB flatness), and requires UUT output levels from 0 to +2.5 dBm back at the input of the PN9002 for proper analysis.
The PN9002 can analyze from 4 to 16 pulses during a measurement, using anywhere from 4 to 128 samples per pulse (depending upon the pulse width) to digitize the analog pulses (at sampling clock frequencies to 50 MHz). The test system generates and processes pulse widths from 200 ns to 500 µs. The PN9002's pulse modulator features rise/fall time of 10 ns, with on time of 30 ns and on/off ratio of 80 dB. The integral pattern generator offers minimum pulse widths of 200 ns with 10-ns rise time at transistor-transistor-logic (TTL) output levels. The system achieves impressive residual noise levels of better than 76 dBc and typically 79 dBc with system-measurement accuracy of ±2 dB. It covers a maximum instantaneous bandwidth of 20 MHz (with bandwidth adjustable by means of a digital Bessel filter).
The test system demodulates all phase-modulation and amplitude-modulation (AM) variations, computing key pulse-to-pulse or intrapulse parameters in terms of peak-to-peak variations, root-mean-square (RMS) deviations, or standard deviations. Since the system includes a Fast Fourier Transform (FFT) analyzer, it can also execute frequency-domain measurements and generate results in terms of spectral displays, working with user-defined Doppler filters.
Software for the system is written for the Windows XP Pro operating system. The software supports a variety of FFT windowing functions, including Hanning, Hamming, and Blackmann functions. The software also simplifies time-domain processing functions, including multiple interpolations, peak-to-peak calculations, RMS calculations, and determinations of standard deviations.
The basic ("starting") PN9002 system includes a generator rack with a pattern generator, low-noise frequency synthesizer, and pulse modulator, as well as an analyzer rack with a noise module, phase/amplitude-modulation detector, video shifter/low-noise amplifier (LNA), and signal-processing module. The basic system also includes a programmable phase shifter, control unit with display, mouse, and keyboard. P&A: $160,000 and up; 12 wks. Aeroflex, Inc., 35 South Service Rd., Plainview, NY 11803; (516) 694-6700, FAX: (516) 694-4823, Internet: www.aeroflex.com.