RFDigRF Interface in Mobile Devices: Definition, Versions, and Specs
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This page covers the basics of the DigRF interface and provides links to manufacturers of DigRF-compliant devices and testing solution providers. DigRF is a digital interface standard used to connect the baseband IC and RF IC.
It’s a standard that allows chips from different manufacturers responsible for baseband processing and RF functions to be seamlessly interconnected. It’s primarily designed for RF and baseband integration within mobile handsets.
The DigRF interface specifications are finalized by the working group members of the MIPI alliance. Several versions have been released, including DigRF v3 and v4. DigRF v3 supports a data transfer rate of about 312 Mbps, while v4 supports about 1.5 Gbps. This makes it suitable for LTE and mobile WiMAX handsets/devices that support MIMO (multiple-input and multiple-output) antenna technology.
DigRF Interface Specifications
The following diagram depicts the DigRF v3 serial data bus with 6 lines. Both data and control commands are transmitted over the same lines. The clock signal is used to synchronize data transfer between the baseband and RF parts.
As shown in the figure, the v3 DigRF interface supports full-duplex data transfer and uses differential signaling. A drawback is that it is not backward compatible with v1.12.
As shown here, the DigRF v1.12 interface has 8 lines between the baseband and RF sections. Rx and Tx data/commands flow on the same line (RxTxData), but only one at a time, based on the enable signal (RxTxEn).
The RFIC (RF Integrated Circuit) is primarily used to configure the RF channel frequency, bandwidth, power setting (used for gain control), PLL setting (used for frequency control), and to enable TxON (Transmit radio ON) and RxON (Receive radio ON).
DigRF References
The latest releases of the DigRF interface specifications are available at the following link:
https://www.mipi.org/specifications/digrfsm-specifications
DigRF v1.12, EGPRS version can be downloaded from the following link:
https://www.docstoc.com/docs/53386199/DigRF-BASEBAND-RF-DIGITAL-INTERFACE-SPECIFICATION
