- Buyers Guide
Military Microwaves Supplement
Aeroflex/Weinschel introduces a series of Programmable Step Attenuators that provide attenuation from 0 to 70 dB or 0 to 110 dB in 10 dB steps. These attenuators provide programmable adjustments of RF signal levels in precise steps of 10 dB and consist of a cascaded assembly of switched attenuator cells. The attenuator elements located in the attenuator cell are created by a thin-film process that provides exceptional long-term stability, low power and temperature coefficients. This series uses a reed switching structure that provides rapid switching together with low insertion loss. The 153 series in available in three cell (153-70) and four cell (153-110) configurations.
In each programmable step attenuator, solenoid are used to switch the internal resistor card of each cell into and out of the circuit. With positive voltage applied to the common pin (#6) the state (attenuator card or thru line) of a particular section is determined by connecting its attenuator card or thru pin to ground. Once the cell is switched, the solenoid is magnetically latched into position and is able to withstand extreme shock and vibration. Internal circuitry is included to interrupt the coil current after switching is complete. This reduces power dissipation even if power is continuously applied. The switching time for each cell is rated at 20 msec maximum, which includes the contact settling time. Also integrated in the design is solid-state DC switching circuitry that avoids the relatively high failure rate of mechanical DC switches. Each attenuator section is controlled by its own driver circuit, which requires +24 V nominal, 125 mA.
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