The difference between FPD-Link and GMSL

FPD-Link, which stands for Flat Panel Display Link, is a high-performance serial data transmission technology introduced by National Semiconductor in 1996. It is designed to transfer video data from a computer's graphics processing unit (GPU) to a flat panel display, especially a liquid crystal display (LCD). 

However, in 2011, Texas Instruments (TI) acquired National Semiconductor. Since then, TI has further optimized and improved the FPD-Link technology, so that its performance, bandwidth, transmission rate, power consumption, integration, application range, and other aspects have been significantly improved.

GMSL refers to the Gigabit Multimedia Serial Link, a high-speed serial interface technology introduced by Maxim Integrated (now part of Analog Devices), enabling efficient transmission of audio, video, and control signals, widely used in automotive and industrial applications. 

The core technology of GMSL is Serializer/Deserializer (SerDes). Firstly, it converts parallel data into serial data. Then it transmits the data at higher frequencies by coaxial cables or shielded twisted-pair (STP) cables. Finally, it reconverts the received serial data into parallel form.

1. Data Transmission Rate: 

FPD-Link: FPD-Link includes three versions: FPD-Link I, FPD-Link II, and FPD-Link III. The transmission rate of FPD-Link II is up to 3 Gbps, and FPD-Link III can support rates of up to 6 Gbps.

GMSL: Now the latest version of the GMSL series is GMSL3, but GMSL2 is the most widely used version. GMSL2 supports transmission rates of up to 6 Gbps, while GMSL3 can reach up to 12 Gbps, making it suitable for handling high-resolution video streams, including 1080p, 4K, and 8K.

2. Transmission Distance

FPD-Link: FPD-Link is suitable for short-distance signal transmission, usually the distance is 10-15 meters.

GMSL: Compared to FPD-Link, GMSL enables stable and reliable data transfer over longer distances (about 15 to 20 meters) via coaxial cables or shielded twisted-pair cables.

3. LVDS Technology 

FPD-Link: FPD-Link adopts the LVDS technology, which can effectively simplify the wiring complexity and cost by reducing traditional parallel RGB signals (more than 20 cables) to only a few differential signal lines for transmission.

GMSL: GMSL uses an improved version of differential signal transmission technology. Compared with traditional LVDS, it not only transmits signals, but also adds additional specialized coding and error correction capabilities.

4.  Anti-Interference

FPD-Link: FPD-Link features good anti-interference ability, suitable for low noise environment. However, the anti-interference ability of FPD-Link may not be as good as that of GMSL in the environments with strong electromagnetic interference.

GMSL: GMSL provides greater noise suppression to ensure more stable signal quality, especially in complex and high-noise environments.