Test and generate DigRF signals

Martin Rowe, Senior Technical Editor -- Test & Measurement World, 10/7/2008

Mobile RF devices such as cell phones have an RFIC front end with a digital bus on the back end that connects to a broadband IC. That digital bus, known as DigRF, has recently been upgraded from version 3 to version 4. The DigRF v4 increases bus speed from 300 Mbps to 1.5 Gbps so that it can keep up with LTE (Long-Term Evolution) and WiMAX protocols. Agilent’s DigRF v4 tester can both analyze and generate digitized RF signals as they travel over the DigRF v4 bus.

The DigRF tester consists of a chassis that can hold up to two modules. The DigRF v4 tester’s analyzer module (N5344A) captures the digital RF signals between the RFIC and baseband IC and analyzes them for I/Q modulation and signal integrity at the physical layer, and communication protocols at higher layers. The bus-exerciser module (N5343A) generates DigRF signals into the RFIC and you can analyze them in the RF domain with a signal analyzer once transmitted. You can also connect an RF signal generator to the device under test and analyze DigRF signals coming from the RFIC under test with the analyzer module. Software lets you control the DigRF tester, a signal analyzer, and a signal generator from a PC through an Ethernet port. Both modules also support DigRF v3, which is incompatible with DigRF v4.

Because the DigRF tester operates on a digital bus, you need high-speed probes. The tester is available with Agilent’s Soft Touch probe, with less than 200 fF of loading capacitance and with flying leads that use resistors to minimize reflections and loss.

Prices: Chassis $4000, N5343A exerciser and N5344A analyzer modules start at $15,000. Active probe pricing starts at $22,000. 

Agilent Technologies, www.agilent.com/find/digrf.