ProductFeature The Next Evolution of Digital/ Programmable Attenuation Aeroflex / Weinschel Frederick, MD A ATTENUATION (dB) t the heart of this digital attenuation solution is a series of USB/TTL controlled MMIC digital attenuators and Ethernet controlled rack mountable subsystems that is suitable for a multitude of RF and microwave applications up to 6 GHz. Designed with budget and performance concerns in mind, these devices offer superior DB (S(2, 1)) 0pt5 DB (S(2, 1)) 1 RF characteristics DB (S(2, 1)) 2 DB ( S(2, 1)) 16 and performance DB (S(2, 1)) 4 DB ( S(2, 1)) 32 suitable for auDB ( S(2, 1)) 8 tomated bench CELL ATTENUATION vs. FREQUENCY testing in wireless 0 backhaul, fading –5 –10 simulation and –15 other high perfor–20 mance wireless –25 applications. All of –30 these models are –35 200 2200 4200 6000 RoHS compliant. FREQUENCY (MHz) The USB/TTL controlled MMIC digital attenuators, s Fig. 1 Attenuation versus frequency plot. Model 4205 Series, 126 are available in three attenuation configurations up to 95.5 dB in 0.5 dB steps and operate over the 0.2 to 6 GHz frequency range. These devices are supplied with both parallel-TTL and USB 2.0 interfaces. The mode of operation is determined by the source of DC power to the unit. Note: The two interfaces cannot be used in a simultaneously use configuration. TTL Control: Two pins are specified for supply voltage and ground. The remaining pins will accept TTL control signals to activate or de-activate a particular attenuation cell. A TTL high will energize a cell to the high attenuation state, whereas a TTL low will maintain a cell in its zero attenuation state. The TTL control connector is an AMP-Latch 10 pin ribbon cable connector that mates with AMP P/N 746285-1 which is supplied with each device. USB Control: The USB interface is compatible with standard USB 2.0 interfaces. In USB mode, DC power to the attenuator is provided by the host USB connection. The attenuator operates as a USB CDC device and accepts simple ASCII text commands. This allows the unit to be controlled from any system capable of sending data via a standard COM MICROWAVE JOURNAL n JANUARY 2014 ProductFeature port-style interface. The USB port is a 5-pin female series B mini socket and mates with most standard USB 5-pin male series B mini plug connectors. These devices offer uninterrupted RF when changing attenuation dB values with excellent solid-state repeatability and performance. Available in three ranges of 0 to 31.5 dB, 63.5 dB and 95.5 dB configurations (see Figure 1). Tables 1 through 4 show the performance specifications. Control software is also included with each device. Aeroflex / Weinschel’s LabVIEW based USB Control Center Software (AUCS) can also be used in the operation of this series of digital attenuators. The AUCS will allow the user to set up, control and perform test and measurements using TABLE I SPECIFICATIONS FOR THE MODEL 4205 SERIES Nominal Impedance 50 Ω Frequency Range 0.2 to 6 GHz Power Rating +23 dBm maximum Switching Speed 1 μsec maximum Control Logic TTL or USB Operating Voltage +5 V @ 50 mA Temperature Range 0° to + 70°C these digital attenuators over a standard USB 2.0 communication interface. The low profile design of the Model 4205 Series and convenient 12 mounting holes on the front, sides, top and bottom ends allow for mounting in any subsystem / rack configuration. With this in mind, Aeroflex / Weinschel offers a standard line of half-rack (Model 8320) and full 19 inch rack turn-key solutions (Model 8321 & 8331) containing these devices that offer USB, Ethernet control or front panel operation. Attenuation matrices and custom configurations can also be designed using these building block components. These units are also supplied with LabVIEW based control software. These devices are already employed in specific applications that include simulation of the cell phone-to-base station RF link; simulation of the WiFi client-to-access point RF link; precise power level control of RF and microwave signal generators. Aeroflex / Weinschel, Frederick, MD (301) 846-9222, www.aeroflex.com/Weinschel. TABLE II ATTENUATION ACCURACY (dB) dB Range 4205-31.5 4205-63.5 4205-95.5 1 to 7.5 dB ±0.5 ±0.5 ±0.5 8 to 11.5 dB ±1.0 ±1.0 ±1.0 12 to 31.5 dB ±1.25 ±1.25 ±1.25 or 4% 32 to 63.5 dB — ±1.25 ±1.25 or 4% 64 to 85 dB — — ±1.25 or 4% 86 to 95 dB — — ± 5% TABLE III MAXIMUM INSERTION LOSS (dB) Frequency (GHz) 4205-31.5 4205-63.5 4205-95.5 0.2 to 3 3 4.5 6.5 3 to 6 4 6 8 4205-31.5 4205-63.5 4205-95.5 0.2 to 0.8 1.50 1.80 2.00 0.8 to 5 1.50 1.50 1.60 5 to 6 1.70 1.50 1.90 TABLE IV MAXIMUM SWR Frequency (GHz) 128 MICROWAVE JOURNAL n JANUARY 2014