Jack Browne
Technical Director
Many test applications require fast-switching signal-generation capability. For example, measurements calling for a large number of data points, such as in antenna testing, automatic- test-equipment (ATE) systems, and radar-cross-section (RCS) measurements, can shave hours off the total test time with a fast-switching test-signal source. To fill those requirements, Anritsu Co. (Morgan Hill, CA) has developed the MG37022A microwave signal generator with switching speed of 100 s per point from 2 to 20 GHz. A frequency-extension option (Option 4) brings the frequency range down to 10 MHz by means of a digital downconverter (DDC) with successive divideby- two circuitry.
The model MG37022A microwave signal generator (see figure) gains speed by substituting high-performance voltage- controlled oscillators (VCOs) as the microwave sources in place of the yttrium-indium-garnet (YIG) oscillators used in earlier members of the MG37000 series of signal generators. The switch brings an order of magnitude faster frequency-switching speed than the company's YIG-based signal generators, while still achieving excellent spectral purity. The MG37022A, for example, features typical phase noise of -105 dBc/Hz offset 10 kHz from a 10-GHz carrier.
The MG37022A can switch in phaselocked steps as small as 0.001 Hz through 20 GHz. Operators can choose from a variety of different sweep modes, including setting the total time of a sweep, including the lock time, from a start frequency to a stop frequency, or selecting a manual sweep between two limits with a user-defined number of steps or step size. In addition, an operator can use the MG37022A's list sweep mode to switch among a group of steps, from 1 to 10,000 steps, with that same frequency resolution and with adjustable dwell times between steps from 50 s to 30 s. The fastswitching signal generator provides as many as 20 independent markers with marker resolution of 0.001 Hz.
In its standard configuration or with the lower-frequency extension, the MG37022A delivers +17 dBm maximum leveled output power. With a highpower option (Option 15), it can provide as much as +23 dBm output power from 2 to 20 GHz. With an optional step attenuator (Option 2) to output level can be controlled to typically as low as -110 dBm. Harmonic-related output content is no worse than -40 dBc below 2 GHz (with Option 4) and better than -50 dBc from 2 to 20 GHz.
The signal generator derives its accuracy from an internal 10-MHz frequency reference source with better than 2 X 10-9/day aging rate and better than 2 X 10-8/C frequency stability with temperature from 0 to +50C. When even better stability is required, the MG37022A can work with an external 10-MHz reference source at 0 to +20 dBm.
The user interface for the MG37022A should be familiar to many operators, since it is based on the Windows XP Professional operating system. The signal generator offers a host of connectivity features, including Universal Serial Bus (USB) 2.0, Ethernet local-area network (LAN), IEEE-488 GPIB, and RS-232.
Anritsu Co., 490 Jarvis Dr., Morgan Hill, CA 95037-2809; (408) 778- 2000, FAX: (408) 776-1744,
www.us.anritsu.com