Abstract: A television receiver receiving an analog video signal, comprises additional information detecting means for separating and extracting an additional information code from the analog video signal, and outputting the additional information code; additional information recording means for recording the additional information code output from the additional information detecting means; additional information writing switch means for passing or blocking the additional information code that is output from the additional information detecting means toward the additional information recording means, in response to a control signal; conversion means for converting the additional information code output from the additional information detecting means or the additional information code reproduced from the additional information recording means into a character or an image; and signal synthesizing means for synthesizing the analog video signal and the additional information that has been converted into a character or an

Abstract: A television receiver receiving an analog video signal, comprises additional information detecting means for separating and extracting an additional information code from the analog video signal, and outputting the additional information code; additional information recording means for recording the additional information code output from the additional information detecting means; additional information writing switch means for passing or blocking the additional information code that is output from the additional information detecting means toward the additional information recording means, in response to a control signal; conversion means for converting the additional information code output from the additional information detecting means or the additional information code reproduced from the additional information recording means into a character or an image; and signal synthesizing means for synthesizing the analog video signal and the additional information that has been converted into a character or an

Abstract: A television receiver receiving an analog video signal, comprises additional information detecting means for separating and extracting an additional information code from the analog video signal, and outputting the additional information code; additional information recording means for recording the additional information code output from the additional information detecting means; additional information writing switch means for passing or blocking the additional information code that is output from the additional information detecting means toward the additional information recording means, in response to a control signal; conversion means for converting the additional information code output from the additional information detecting means or the additional information code reproduced from the additional information recording means into a character or an image; and signal synthesizing means for synthesizing the analog video signal and the additional information that has been converted into a character or an

Abstract: A diffraction grating has a reflection film formed on a photosensitive layer disposed on a substrate through exposure followed by development and the groove profile thus formed has a configuration distorted from a sinusoidal form because the sensitivity curve of the photosensitive layer is of the second order non-linearity to the exposure amount. With the groove pitch expressed by d, K=2 .pi./d, the coordinate perpendicular to the groove direction taken as x, and the groove profile .eta.(x) expressed as .eta.(x)=h [sin (Kx)+.gamma.sin (2Kz-90.degree.)], the parameters h, .gamma. and .phi. satisfy as follows:0.26.ltoreq.2h/d.ltoreq.0.520.05.ltoreq..gamma..ltoreq.0.32.The wavelength region to be used is normalized by the groove pitch d as 0.67.ltoreq..lambda./d.ltoreq.1.15. When an incident angle is expressed by .theta. and the first order Littrow angle is expressed by .theta..sub.L, the mount to be used is carried out in such a region that satisfies the following expression:.theta..sub.L -5.degree..ltoreq..

Abstract: Disclosed is a frequency stabilized light source including a semiconductor laser chip and a finite Fourier diffraction grating with a corrugated profile with a continuous first order differential coefficient. The laser chip emits the output light from its one facet into the diffraction grating with the diffracted light from the grating being fed back to the laser chip, so that the laser chip emits the output light with a stable wavelength from its another facet. The arrangement produces the output light with high frequency purity and high adjustment accuracy and yet wide frequency tunable range.