Method and apparatus for magnetic recording digital video signals and magnetic recording medium therefor

#1. Field of the Invention

#This invention relates generally to a method and apparatus for the magnetic recording of digital video signals and to a magnetic recording medium for use therein.

#2. Description of the Prior Art

#FIG. 1 is a block diagram showing a signal processing portion of a recording circuit in a digital VTR according to an embodiment of the present invention;

#FIG. 2 is a block diagram showing a signal processing portion of a playback circuit in the digital VTR according to the invention;

#FIG. 3 is a schematic diagram showing an example of a block-by-block encoding;

#First, a signal processing portion of a recording circuit in a digital VTR according to an embodiment of the present invention will be described with reference to FIG. 1 in which a digital luminance signal Y and digital color difference signals U and V, are supplied to input terminals 1Y, 1U, and 1V, respectively, after being formed from three primary color signals R, G, and B output from, for example, a color video camera. In this case, the clock rates of the signals Y, U and V are the same as the frequencies of the component signals in the above described D1 format. In other words, the sampling frequencies are 13.5 MHz and 6.75 MHz for the luminance signal Y and for the color difference signals U and V, respectively, and there are eight bits per sample. Thus, the data rate of the signals sent to the input terminals 1Y, 1U, and 1V is approximately 216 Mbps as was described earlier. An effective information retrieval circuit 2 for removing data from the signals during the blanking intervals and for retrieving only information in the effective area compresses the data to a data rate of approximately 167 Mbps. The luminance signal Y output by the effective information retrieval circuit 2 is sent to a frequency conversion circuit 3 which converts the sampling frequency from 13.5 MHz to 3/4 thereof, that is, to 10.125 MHz. A thin-out filter may be used for the frequency conversion circuit 3, so as to prevent reflected distortion from taking place.

#The output signal from the frequency conversion circuit 3 is sent to a block segmentation circuit 5 which converts the series luminance data into a sequence of blocks. The block segmentation circuit 5 is provided to condition the data for processing by a block encoding circuit 8 disposed at a later stage of the recording circuit.

#Reference to FIG. 3 will show a construction of three-dimensional blocks which are used as an encoding unit. By dividing a screen which occupies for example two frames, as shown in FIG. 3, a large number of unit blocks (4 lines.times.4 picture elements.times.2 frames) are formed. In FIG. 3, the solid lines represent lines of odd fields, while the dotted lines represent lines of even fields.