Abstract: A characteristic control system for a digital equalizer comprises a digital equalizer constructed from a digital filter, for directly giving a desired equalizing characteristic with respect to a digital pulse-modulated signal, and a control part for changing the equalizing characteristic of the digital equalizer from a first arbitrary characteristic to a second arbitrary characteristic so that one or a plurality of intermediate equalizing characteristic is obtained before reaching the desired second arbitrary characteristic.

Abstract: A digital editing system includes first and second memories in which audio data and weighting factor data are respectively stored. The audio data are sequentially retrieved from the first memory and multiplied by corresponding weighting factor data retrieved from the second memory. A coincidence detector detects when predetermined storage locations of the memories are addressed. The weighting factor data has a unity or zero value during the time prior to the occurrence of an output from the detector, whereupon it changes its value as a function of time until it reaches to zero or unity and remains at the final value thereafter. The direction of variation of the weighting factor data can be appropriately selected to modify the audio data into a so-called "fade out" of "fade-in" pattern at a desired point of the audio program. A pair of such editing systems is required for editing audio programs from different sources for storing such programs in a pair of first memories.

Abstract: Prerecorded audio or video information signals including address data indicating the location of synchronized signals from a plurality of synchronized sources are supplied to a single separation circuit via a switching circuit. The separation circuit, selectively connected to one of the signal sources via the switching circuit, separates the address data from the audio or video information of the connected signal source. A register connected to the separation circuit receives the separated address data which constantly updates the register contents. At least one counter is reset to the contents of the register each time a newly selected signal source is connected to the separation circuit to load the address data of the previously connected signal source into that counter. At regular intervals one binary increment is added to the counter address data so that the counter count value corresponds to the address data of the previously connected signal source.

Abstract: A compressing system for digital modulated signals comprises an analog-to-digital converter for obtaining a digital modulated signal by digitally modulating an analog signal; a first variable gain circuit provided at the output side of the analog-to-digital converter; and a first gain control circuit for equivalently performing level-compression of the analog conversion level of the input digital modulated signal of the first gain control circuit within a predetermined level range by use of a first control signal and the first variable gain circuit. The first gain control circuit comprises an expected signal generating circuit having an analog conversion level z.sub.n which satisfies the equation ##EQU1## (N is an arbitrary natural number, and a.sub.O through a.sub.N are zero or an arbitrary number) where y.sub.

Abstract: A stylus for cutting a sound groove on a disc recording medium comprises a diamond body having a groove cutting part, for producing a chip cut from the disc recording medium. The stylus also includes a structure made of a material which does not readily generate static electricity when the chip is in sliding contact therewith. The non static electricity generating material is at a position on the cutting stylus body which is contacted by the chip.