Abstract: Digital tone control arrangement for a digital audio signal, comprising a recursive digital filter whose transfer function contains as many poles as there are zeros, the recursive filter also comprising a recursive portion and a non-recursive portion each receiving filter coefficients which are stored in a memory means. So as to limit the total number of filter coefficients the memory means is divided into a first memory field for storing a first sub-group of filter coefficients and into a number of second memory fields in each of which a second subgroup of filter coefficients is stored. By means of a switching device the first subgroup of the filter coefficients is applied either to the non-recursive portion or to the recursive portion and a selected second subgroup of filter coefficients is applied to that portion (recursive and the non-recursive) to which the first subgroup of filter coefficients is not applied.

Abstract: Digital filter for filtering nonuniformly quantized pulse code-modulated signals formed by a sequence of code words each comprising a segment number s(i) and a mantissa number m(i). This digital filter comprises a modifying device to which the mantissa numbers m(i) are applied for generating modified mantissa numbers E(i). The numbers E(i) are each multiplied by the magnitude of a filter coefficient, for generating first product numbers z.sub.1 (i). Thereafter these numbers z.sub.1 (i) are each multiplied by a number 2.sup.B(i), B(i) being either equal to s(i) or equal to s(i)-1, so that second product numbers z.sub.2 (i) are obtained which are applied to an accumulator.

Abstract: Digital filter for filtering non-uniformly quantised pulse code modulated signals formed by a sequence of code groups x(i), each comprising a polarity bit, a segment number and a mantissa number. This digital filter arrangement comprises a generator which cyclically generates a series of sequentially occurring auxiliary numbers each comprising a polarity bit and an address code; a first storage medium 1 for storing the code groups x(i) and controlled by an address computation circuit 13 to which the auxiliary numbers are applied; a second addressable storage medium 2 to which a segment number s(i-h) a mantissa number m(i-l), supplied by the first storage medium 1, as well as a polarity bit supplied by an exclusive OR-gate 3 are applied as the address code. This polarity bit is derived by gate 3 from the polarity bit p(i-l) of the code groups x(i) and the auxiliary numbers polarity bit. This second storage medium 2 contains positive numbers z.sub.p and negative numbers z.sub.

Abstract: Digital adding device for determining the sum of a plurality of binary coded numbers, having a digital parallel-accumulator having a first store for storing intermediate sums and intermediate carries which can be taken over into a second store by means of a switching circuit in order to be processed to the final sum in a final adder. This enables the use of the digital parallel-accumulator for determining consecutive sums in a more efficient manner.

Abstract: Non-recursive digital filters having an output sampling frequency which is a factor of r lower than the input sampling frequency. A number of filters are described in which for each value of r and N (N being the number of filter coefficients) the time which is required to calculate an output sample is based on the output sampling period T.sub.u. This is achieved by using a storage device in the input circuit.

Abstract: Arrangement for converting a differential code into an absolute code which comprises a non-recursive interpolating digital filter, to which input code words are applied, with a sampling frequency f.sub.s, for supplying auxiliary code words occurring with an increased sampling frequency mf.sub.s, and a digital intergrator for converting the auxiliary code words into output code words, also with a sampling frequency mf.sub.s.

Abstract: A digital filter for generating digital output signals from information signals in accordance with a predetermined transfer characteristics includes a coefficient number generator for supplying digital numbers which indicate the values of coefficients which represent the transfer characteristic. The coefficient number generator includes a device for storing increments of successive coefficient values in numerical form and a decoder connected thereto for recovering the coefficient numbers from the numbers stored in the storage device.

Abstract: A transmission system for the coded transmission of information signals in which the transmitter and receiver comprise a dynamic control circuit, in which a signal generator is included for supplying a dynamic control signal.When a pulse train analyzer which analyzes the transmitted pulse train delivers a series of one-pulses, an exponential variation of the dynamic control signal is obtained by actuating a feedback circuit which applies the dynamic control signal to the input of the signal generator.