Abstract: In a circuit supplying a digital system, the frequency at which the switching device therein is controlled is synchronized to be the same as one or several times half the sampling frequency. In this way, the original frequency spectrum can be kept free from interfering signals.

Abstract: There is disclosed a method of digital signal transmission in which, for serially transmitting digital data of N channels, where N may for example be 16, 24 or 32, these data are serially and successively transmitted in groups of M, where M may for example be 2, 3 or 4, with each said group including data of K channels, where K may for example be 8, and in which a preamble with a pattern violating the rule of modulation for data transmission is provided, for example, at the foremost part of each such group, a data validity evaluation bit is added to the data of each such channel, and parity data is also provided to the totality of bits of each such group. A group address may also be provided to each such group for indicating its group number within the M groups.

Abstract: In the conversion of a first delta modulated signal with a first bit rate into a second delta modulated signal with a second bit rate, a first and second digital signal derived respectively from the first and second delta modulated signals are compared together in an adding circuit (58) followed by an integration circuit (55). In this way an analog intermediary signal can be avoided and the circuit complexity is small.

Abstract: Described is a method for PCM signal recording in which, when single-channel or multichannel PCM signals are recorded so that one-channel PCM signals are recorded in plural recording tracks, the input PCM signals of one channel are correspondingly distributed to the plural recording tracks with at least one word as a unit, and in which the distributed plural signals are subjected to an encoding operation independently of one another and are recorded on the plural recording tracks. In distributing the input PCM signals by word units, word groups consisting of a predetermined number of consecutive words are sequentially distributed to the recording tracks, or plural consecutive words equal in number to the number of recording tracks are distributed to the tracks.

Abstract: For both recording and replay, a digital audio tape (14) is accelerated very rapidly by a motor servo (9), motor (8) and capstan (7) so that the tape speed overshoots nominal speed range before settling back to this range in an oscillatory manner. The digital samples are recorded and replayed via a head (15), a random access memory (16) and input/output electronics (19). During recording, the store (17) is precharged by starting to write in as soon as acceleration is initiated. Read-out to the tape is initiated as soon as the tape first reaches the nominal speed range. Uniformity of samples as recorded on the tape is preserved by clocking a read address generator (21) at a rate proportional to tape speed, signaled by a tachometer (7). The write address generator is clocked at the constant sampling rate. For replay the write address generator is clocked at the tape speed rate while the read address generator (21) is clocked at the constant sample rate.

Abstract: In producing an edited tape (31) the lead-in material up to a first edit point is separated from the lead-out material running from a second edit point by a space containing unwanted material and accommodating the actual or notional splice. The unwanted material ensures correct operation of error protection for all of the wanted material on replay. The first and second edit points are marked by codes placed on the tape (31) by a code processor (43) and supplementary head (42). During replay the digital data recovered from the tape by a head (32) is entered into a random access buffer store (34) under control of a write address generator (38) and read out to output electronics (37) under control of a read address generator (39) running at the audio sampling rate.

Abstract: Equidistant timing pulses are counted during the time between the arrival of a first pulse edge of a first signal sequence and the arrival of a following second pulse edge of another signal sequence and are averaged to a mean value with equidistant timing pulses of an immediately preceding count between two pulse edges of the two signal sequences. The continuously formed mean values are accumulated with mean values of preceding cycles and in each case the least significant bit is further processed.

Abstract: A multitrack tape recorder records and replays digital data on a plurality of data tracks (15) by way of record/replay electronics (7), a record head (5) and a replay head (6). Channels (8) corresponding to the tape track (15) are provided for input to and output from the electronics (7). An additional channel (11) carries auxiliary data related to the signals in the channels (8). This data is formatted during recording by the electronics (7) into a block format compatible with the data format on channels (15) and is recorded on a separate dedicated track (16). The auxiliary information may be formatted in labels each of which has an instruction field and a parameter field. The labels can carry a wide variety of information relating to operation of the system. As one example, a label may contain in the instruction field an instruction to increase the playback gain by an amount contained in the parameter field.