Abstract: A trellis code of a special class is encoded by employing a binary convolutional code with a small constraint length, followed by a convolutional processor and a signal mapper. The trellis code is decoded by the trellis of the binary convolutional code.

Abstract: This invention is a decoding method for a special class of trellis codes which have large free distances. The encoding of the trellis code to be decoded can be implemented by employing a single binary convolutional code followed by more than one processor. The decoding can be implemented by using the trellis of the binary convolutional code and additional processors.

Abstract: A palm-top wireless trackball including a mainframe to hold a circuit board on the inside, a hand-hold portion defined within said mainframe and having two smoothly curved opposite sides fitting the palm and the finger cushions, an operation area in the hand-hold portion, a smoothly curved stop flange raised from the bottom of the operation area, a transverse groove adjacent to the stop flange for resting the middle finger, and a transparent shade covered on the operation area to hold a transmitter on the inside, permitting the transmitter to be controlled by the circuit board, a circular ball holder raised from the top side of the operation area to hold a trackball for permitting the trackball to be rotated within the ball holder to trigger the circuit board in sending a corresponding radio signal through the transmitter, a drag key disposed in front of the smoothly curved stop flange and connected to the circuit board for operation by the forefinger, and an enter key transversely mounted on the hand-hold po

Abstract: A sofabed which includes a first base frame serving as the seat of a sofa or the bed piece of a bed and defining a space for keeping pillows, quilts, etc., a second base frame retractably connected to the first base frame and moved between the retracted position received inside tile first base frame and the extended position to serve as the base frame of a second bed, a seat frame supported on the first base frame, a second seat frame pivoted to the first base frame and set at the desired angle to serve as the back of the sofa the bed piece of the second bed, and two armrest frames adjustably connected to the first base frame at two opposite ends.

Abstract: This invention relates to a video display high voltage generator. In the generator, the primary coil, the high voltage coil and the multiple foil high voltage capacitors of the multiplier are sequentially formed into a trausformer assembly on the insulating tube. The stepup capacitors are formed through an electrostatic induction of the metallized foil in the assembly, the two groups of the stepup capacitors are wound on the high voltage coil in opposite directions so as to nullify the voltages magnetically induced thereon, forming the wound metallized foils into pure capacitors without causing electromagnetic interference on the other equipments. The transformer assembly is mounted on the center pole of the ferrite casing and accomodated in the space provided by the casing. The magnetic path is formed by the center pole bases and rim of the ferrite casing.

Abstract: This invention is a multilevel trellis coding method which employs a single binary convolutional code and is called a single-stage and multilevel trellis coding. This invention can be generalized by combining several single-stage multilevel codings together to form a multilevel trellis coding for which the number of stages is less than the number of coding levels. New trellis coded modulation systems and binary trellis coding systems which are designed by the aforementioned trellis coding method are better than the currently known coding systems if the communication channels are additive white Gaussian noise (AWGN) channels.