March 3, 2008
The DigRF working groups is comprised of representatives from RF-IC development companies, Baseband-IC development companies and mobile wireless communications OEMs. The charter of the DigRF working group is to define digital serial interfaces between Baseband ICs and RF-ICs. The DigRF digital serial interfaces are being defined to enable interoperability between RF-ICs and BB-ICs from different suppliers. Additional benefits that can be realized by utilizing the DigRF standards include reduced cost as a result of reduced pin count and extended battery life as enabled by high speed low power and sleep modes.
The DigRF v3 digital serial interface standard is in the final approval stage. Many of the leading RF-IC suppliers and BB-IC suppliers are developing their next generation components based upon the DigRF v3 specification. The DigRF v3 standard supports a variety of 2.5G and 3GPP air standards including GSM, EDGE, CDMA, CDMA-2K and W-CDMA. The DigRF v3 standard is comprised of separate transmit and receive differential signal pairs along with SYSCLK and SYCLKEN. A variety of control packet and data (IQ) packet formats are defined with the DigRF v3 standard and driven between the RF-IC and the BB-IC over the prescribed electrical interface.
The challenge for Teat and Measurement companies is to provide cross domain solutions for RF-IC development teams, BB-IC development teams and RF-IC / BB-IC integration teams. Aided by cross domain solutions, development teams will be able to capitalize on the benefits of DigRF v3 standard to build competitive advantage.
Agilent Technologies, with its portfolio of RF products (Signal Sources, Spectrum Analyzers, Network Analyzers and RF EDA tools) coupled with its portfolio of digital products (Logic Analyzers, Protocol Analyzers and Oscilloscopes) is uniquely positioned to provide cross domain measurement solutions to the mobile wireless industry.
Agilent Technologies Agilent solutions enable handset integration teams to quickly evaluate product behavior by monitor the digital serial bit stream between the RF-IC and BB-IC.
DigRF v3 control packets are decoded and displayed on the logic analyzer to provide visibility into the configuration, status and control flow. IQ data is extracted from the DigRF v3 data packets and analyzed using the 89601A vector signal analysis package. With these capabilities, handset integrators can characterize the interactions between the RF-IC and the BB-IC to isolate defects and optimize performance. The logic analyzer can monitor visibility ports on the BB-IC to provide additional insight into system behavior.
Agilent solutions enable RF-IC development teams to completely characterize their components independent of the BB-IC.
The RF-IC transmitter is characterized by developing a digital IQ representation of the RF signal using signal studio and loading it into the logic analyzer. The stimulus probe packetizes the IQ data, inserted the specified control packets and drives the bit stream into the RF-IC over the DigRF v3 interface. The RF-IC processes the serial bit stream and generates an RF signal that is captured by the N9020A spectrum analyzer. Designers can compare the desired RF waveform to the RF waveform as produced by the RF-IC to characterize transmitter behavior.
The receiver is characterized by driving the RF signal into the RF-IC using an E4438C Signal Source. The RF-IC processes the RF signal and renders the digital IQ, which is packetized and driven out in the DigRF v3 digital serial format. The acquisition probe captures the serial bit stream and extracts the relevant IQ data for analysis using the vector signal analysis package. Complex RF-IC characteristics like BER can be evaluated by operating the logic analyzer, signal source and spectrum analyzer under control of Agilent's advanced design system RF EDA software.
The Agilent solutions enable BB-IC development teams to evaluate and tune the behavior of their components independent of the RF-IC.:
Using the acquisition probe, validation teams can monitor transactions on the DigRF v3 interface generated by the BB-IC. Control packets are displayed on the logic analyzer and IQ from the data packets can be evaluated using the vector signal analysis package. The receive path on the BB-IC can be characterized by driving the DigRF v3 interface with IQ data packets from the stimulus probe. The IQ data packets are creating on the logic analyzer using the digital IQ representation of the RF signal generated in signal studio. Visibility ports on the BB-IC can be monitored by the logic analyzer to gain additional insight into BB-IC operation.
The integration of DigRF v3 logic analysis tools and the Agilent RF portfolio provide the cross domain solutions that will enable the rapid deployment of DigRF v3 based products by the wireless industry.
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