Abstract: An apparatus for digital-to-analog conversion and the method thereof is disclosed, wherein the complete scale-tuned levels of more bits may be presented with an output of less bits. The apparatus comprises a timing controller, a scale-tuned circuit and a digital-to-analog converter. The timing controller receives an a-bit grayscale value, and outputs a selection signal and a b-bit control signal, wherein a, b are both positive integers and a>b>=1. The selection signal has two states: if the grayscale value is less than or equal to 2a?2c, wherein c is equal to a?b, the selection signal is in a first state; and if the grayscale value is equal to 2a?2c+n, wherein n is an integer and 0<n<2c, the selection signal has a probability of n/2c to be in a second state, and has a probability of 1?n/2c to be in the first state.

Abstract: The present invention belongs to the field of optoectronics. The main content of the present invention is to determine the optimum cut-orientations of ReCOB crystal frequency-doubling devices. For an example, the cut-angles of the YCOB crystal for 1064 nm are &thgr;1=(65.9±5.0)°, &phgr;1=(36.9±5.0)° or &thgr;2=(66.3±5)°, &phgr;2=(143.5±5)°. The present invention has solved the problem of low frequency-doubling conversion efficiency in the prior technique. The frequency-doubling technique of the present invention has advantages of high frequency-doubling conversion efficiency and low energy dissipation, and is useful for the application of the ReCOB crystal.