Site: Thomson CSF
Thomson Tubes Electroniques
2 Rue Latecoere
SP 23 78141 Velizy Villacoublay Cedex
France

Date Visited: June 25, 1992

Report Author: E. Miller

ATTENDEES

NASA/NSF:

W. Brandon
B. Edelson
E. Miller

HOSTS:

Michel Traizet

Director, Espace

Georges H. Fleury

Space Activities Manager

BACKGROUND

Thomson is a 10 to 12 billion FFr. per year company with about 100,000 employees. Thomson CSF (Aerospace) is about half of that. In 1983-84, space activities were transferred to Alcatel, but recently that agreement was changed. Consequently work has a military/defense emphasis. Thomson is eager to apply military-developed technology to commercial space telecom use, but appears to respond to outside funding for these purposes rather than using internal funding. The exception is the space TWT business where they have a strongly developed commercial product and a substantial share of the market (first in volume and one of only three major space tube manufacturers). Overall company emphasis is to supply components for commercial space communications, not to do systems integration.

Thomson CSF does 115 million FFr. per year business in electron tubes for space, and 20% of that revenue supports R&D. Sixty "hands on" employees (engineers, scientists and technicians) produce these tubes. The staff is well experienced.

RESEARCH AND DEVELOPMENT ACTIVITIES

Electron Tubes for Space Communications

Their design approach employs modular construction, with one tube envelope. They allow only a limited number and range of variables in their designs (helix pitch, for example). New designs are small perturbations of past proven performance. A 14 point test program assures proper performance of the product.

Specific performance levels achieved are given in Table Thomson.1. In general, efficiencies are increasing (from 52% to 62%, over time). Mass is decreasing (down to typically 600 gm from about 900 gm, previously). The HISPASAT TWT achieved 58% efficiency using a three-stage collector. Future performance improvements anticipated include a five to seven percent increase in efficiency using a dual-taper helix design, a mass reduction of 100 gm, and further improvements in linearity.

M-type cathodes are used by Thomson CSF.

Components

Thomson CSF products for space include CCDs for space imaging applications; analog ASICs; A/D converters; digital ASICs (1.2 mm epitaxial); microprocessor - 25 MHz, radiation hardened; microwave components including GaAs MESFETs, a 3 W C-band amplifier for ground radar application, 5- and 6-bit phase shifters for X-band radar applications, and, under study, HBT Technology, to be on market circa 1996-97.

Their RADANT antenna for radar applications provides scanning of a 4 degrees HPBW beam over plus/minus 75 degrees, very low sidelobes (35-40 dB down!), adaptive nulling and tracking capability. Some of this technology has been applied to the SPOT downlink transmission system.

Signal and Image Processing

Extensive video coding work, using expert systems and parallel processing, is being undertaken by Thomson CSF. They have achieved a 6:1 compression of HDTV, which results in a data rate of 140 Mbits/sec. This codec is on the market.

They have also developed improved quality terrestrial transmission at a rate of 38 Mbits/sec transmitted AMVSB in 7.5 Mhz.

Table Thomson.1
TWT Development Status

SUMMARY

Thomson CSF applies state-of-art space TWT technology to space communication. They are ready to apply various technologies from military work to future commercial space communications. TWTs for space draw upon proven performance of ground tubes. Thomson CSF is a recognized leader in the space TWT field.

They also supply other components for space communication. X-band and C-band work was shown to the panel, as was the wide angle scan, very low sidelobe radar antenna. They did not show extensive work at Ku- and Ka-bands.


Published: July 1993; WTEC Hyper-Librarian