up-convertern.

1958 Bell Syst. Techn. Jrnl. 37 989 (heading) Gain and noise figure of a variable-capacitance up~converter.

1968 Microwave Jrnl. Aug. 52/2 The 12·4 GHz signal from the frequency up-converter is first down-converted to 160 MHz..then upconverted to 12·4 GHz in a single frequency parametric upconverter.

1973 F. Zernike & J. E. Midwinter Appl. Nonlinear Optics vii. 153 The parametric up-converter is a special case of sum-frequency generation. Similarly, the parametric amplifier and the parametric oscillator are special cases of difference-frequency generation.

1976 Which? Nov. 262/3 UHF signals received at the aerial are sometimes translated to VHF or even lower frequencies (HF). These VHF (or HF) signals can't be plugged directly into a UHF TV... They need either a box (called an up-converter) to turn them back into UHF signals, or a specially modified TV.

1958 Bell Syst. Techn. Jrnl. 37 989 In up-conversion (modulation) a power gain results, with the power added to the input signal being supplied by the beat oscillator. In down~conversion a power loss results.

1975 D. G. Fink Electronics Engineers' Handbk. xiv. 72 There is a distinct advantage to up-conversion; image rejection is easily achievable by a simple low-pass filter.

1983 E. Trundle Beginner's Guide Videocassette Recorders v. 91 The up-conversion process during replay involves a heterodyne system.

1970 New Yorker 11 Apr. 34 A laser beam can be used to upconvert infrared light to visible light.

1972 Physics Bull. Jan. 18/2 Since the upconverted radiation now has a wavelength close to both the helium–neon and krypton (0·605 μm) wavelengths, an accurate interferometric comparison is much easier to perform than with the 9·3 μm line directly.