SPINNER has been setting standards with its RF technology products for almost 70 years. Its contactless rotating solution is able to transmit HD-SDI SMPTE 292M (1.485Gb/s) and HD-SDI SMPTE 424M (3Gb/s) video signals, including pathological test patterns.

Transitioning from analogue to digital video – especially to HD-SDI 292M or 424M – is not a trivial matter. Normal coaxial cables work with non-rotating applications, but if the system is turning, the digital signal has to pass through the rotary joint.

For cases in which the central axis is blocked (because it contains a mechanical interface or RF components, for example), an acceptable solution has not previously been available in the market for transmitting a signal and a pathological test pattern. SPINNER slightly modified its standard capacitive coupling device to meet the check field requirement, resulting in an ideal eye diagram.

The fibre-optic rotary joint

For HD-SDI signals, SPINNER has adapted a number of hybrid rotary joint units involving signal multiplexers for RS422, RS232, CAN bus, I/O lines, and 1000BaseT Ethernet. One example is a complex installation with three HD-SDI cameras and around 150 RS422 lines. SPINNER designed a fibre-optic rotary joint (FORJ) for it that is half the size of a conventional slip-ring unit and has a mean time between failures of at least 300,000 hours – an improvement of 1,000%.

The SPINNER FORJ 1.17 is engineered for the harshest imaginable environments, able to withstand intense vibrations, strong jolts, high humidity and saltwater.

Such a solution offers the benefits of lower weight, smaller interfaces, lower prices, and an end to issues with terminations and end-to-end resistance. Currently, there are uses for HD-SDI contactless rotary joints in tracking radar, gun and naval optronic systems. They are available with clear internal diameters of 300mm and more. If the central axis is free, a FORJ from SPINNER can be used. Single-mode and multimode FORJs are used in land-based, naval and airborne applications, by themselves or integrated in a slip ring.

The new FORJ 1.14 of SPINNER’s family of single-channel products exhibits outstanding performance despite its compact dimensions. Its superior design reduces the typical insertion losses to less than 1.0dB with single-mode fibres. Its small size, combined with a weight of only 18g, permits it to spin at speeds of 10,000rpm or more. The SPINNER FLEXIFLANGE makes it easy to adapt this rotary joint to different applications.

Quality engineering

The SPINNER FORJ 1.17 is engineered for the harshest imaginable environments, able to withstand intense vibrations, strong jolts, high humidity and saltwater. It was originally designed to meet the needs of offshore and underwater vessels, and has an IP 68 protection rating. The single-channel rotary joint can also be supplied with integrated pressure compensation for deep-sea applications down to depths of 4,500mm, as the special product version SPINNER FORJ 1.17pc.

For harsh industrial environments, SPINNER FORJ 1.22 is rated at IP 65 for protection from dust and humidity. It includes protective tubing for the fibres to prevent them from breaking or otherwise being damaged during or after installation.

The dual-channel SPINNER FORJ 2.28 fills the need for a basic two-channel, single-mode rotary joint. Its patented mechanical system makes it compact, with a total length of just under 90mm and an outer diameter of only 28mm. It is offered in versions including multimode only, or a combination of single and multimode fibres.

The SPINNER FORJ x.40, with an outer housing diameter of only 39.5mm, delivers market-leading compactness for solutions involving up to six channels. It is available in single-mode, multimode and mixed-fibre configurations.