Isao Akitake

A high quality GaAs IC tuner for TV/VCR receivers

A GaAs MESFET IC for a three-band (VHF/CATV/UHF) tuner is described. The IC can be used in TVs or video cassette recorders (VCRs). The IC incorporates VHF/CATV and UHF oscillators, buffer amplifiers for the oscillator signals, a double balanced mixer, a VHF/CATV-UHF switch buffer amplifiers, and an intermediate-frequency (IF) amplifier. Each circuit element is detailed. This IC makes full use of high linearity (low distortion) and the high maximum frequency of GaAs MESFETs. The IC overcomes high 1/f noise by careful circuit design. >

A compact satellite 1 GHz tuner with GaAs ICs

The authors have designed two types of GaAs ICs, an RF amplifier and a converter. The amplifier has a stable input impedance. The converter has two AGC (automatic gain control) system (RF and IF AGC) and a wide input signal range with a good intermodulation characteristic. These ICs make full use of the good input versus output linearity and high mobility of a GaAs MESFET and have been integrated into a small chip. Using these ICs, the authors have developed a 1-GHz satellite tuner. This tuner can receive the 0.95-1.75-GHz BS frequency band and offers novel functions such as reception of two satellite broadcasting signals. The components of this tuner can be reduced by using GaAs ICs, making the most compact tuner to date (40 cm/sup 3/). >

Wide band and low supply voltage ICs for satellite tuner unit

Three ICs for a satellite tuner unit which operate at a low supply voltage of 5 V have been designed. The circuit design of these three ICs and a new tuner unit system are described. Two types of GaAs ICs which operate up to 2.2 GHz and a Si IC which demodulates the FM signal of more than 500 MHz carrier frequency are outlined. Using these ICs, a compact satellite tuner unit with low power dissipation has been successfully developed. It can receive the satellite TV band of 0.95 approximately 2.1 GHz. >