Abstract: In amplifier circuit arrangements for low-distortion transmission of audio signals a transformer is provided in order to isolate a source circuit from an amplifier of the amplifier circuit arrangement. Good transmission characteristics, however, can only be obtained in such circuit arrangements by using transformers of comparatively great dimensions. In order to achieve improved transmission characteristics and yet design the transformer in such a manner as to have small size, to be of low weight and inexpensive, the amplifier of the amplifier circuit arrangement is provided with a negative feedback circuit. This negative feedback circuit is connected to the source circuit by using a transformer connected in series with the current-voltage source of such source circuit.

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.