Tektronix Inc., a Beaverton, Ore., provider of test, measurement and monitoring instruments, has won a five-year contract award to supply digital phosphor oscilloscopes to the US Air Force, from Warner Robins Air Logistics Center. Tektronix will supply 2-channel, 300 MHz; 4-channel, 500 MHz; and 4-channel, 1 GHz models of the devices, which will be used in installation, maintenance and support of electronic equipment and systems including radio, radar and electronic warfare systems. Tektronix recently fulfilled similar contracts from the US Navy for 100 MHz and 500 MHz models.    . . .    Spectra Couleur GmbH, a Berlin, Germany-based supplier of visible upconversion fiber laser systems for life science, imaging, sensor and research applications, has appointed Market Tech Inc., of Scotts Valley, Calif., as its exclusive distributor of laser products in North America. Market Tech provides distribution and sales for a variety of photonics manufacturers.