More ears for the NSA: GSM monitoring receiver
The unit is fit for mobile monitoring systems that must capture some or all of the 1100 uplink and downlink signals in both upper and lower GSM bands. This full global system for mobile communications spectrum monitoring targets homeland security, government and military applications.
Designed for GSM phone signal interception, Model 52663 accepts four analog inputs from an external analog RF tuner, such as the Pentek Model 8111, where the GSM RF bands are down converted to an IF frequency.
These IF signals are then digitized by four A/D converters and routed to four channelizer banks, which perform digital downconversion of all GSM channels to baseband. Two of the banks handle 175 channels for the lower GSM transmit/receive bands and two banks handle 375 channels for the upper bands. The DDC channels within each bank are equally spaced at 200 kHz.
Each DDC output is re-sampled to a 4x symbol rate of 1.08333 MHz to simplify symbol recovery. Every four DC outputs are combined into a frequency-division “superchannel” that allows transmission of all 1100 channels across the PCIe Gen 2 x8 interface.
The GSM channelizer IP core is supported with additional factory-installed FPGA functions including packet formation, time stamping, four DMA controllers, gating and triggering. Baseband super-channel packets are sent via DMA controllers to processor memory where customers apply processing algorithms.
Visit Pentek at www.pentek.com
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