Siemens Aktiengesellschaft

Hans J Mattausch

Matthias Schoebinger

Fred Matthiesen

A semiconductor memory has a recognition circuit for signal changes which deactivates a pre-loading circuit. The pre-loading circuit charges the data lines upon appearance of an address signal change, and then reactivates them again in time-delayed fashion. A clock voltage generator is provided which generates a clock voltage that activates the pre-loading circuit and, given the appearance of an address signal change, switches the clock voltage to a first level that deactivates the pre-loading circuit and, given the appearance of an output signal at the read amplifier, switches this clock voltage to a second level activating the pre-loading circuit.

Semiconductor memory comprising a recognition circuit for signal changes

An arrangement for DPCM-coding of video signals. A DPCM coder wherein estimated values (s) are respectively subtracted from digitized picture element signals (s) and the estimated errors are used for signal transmission after quantization and coding. Every estimated value (s) is derived from a reconstructed picture element signal formed in an adder. A limiter between the first adder and the subtractor that reduces the calculating speed can be removed from the time-critical path in that the limiter function is distributed onto two paths that calculate in parallel. A subtraction of the signal taken at the adder output occurs in the one path; the subtraction of an upper or lower limit value (.alpha..multidot.G.sup.-, .alpha..multidot.G.sup.+) weighed with .alpha. and through-connected via a switch from the respective picture element signal (s) of the input side is carried out on the other path. An overflow recognition element and a multiplexer provide that only a difference of the two differences formed up to this point, that relate to the actual addition result (no overflow, positive overflow, negative overflow), is through-connected to a quantizer.

Arrangement for DPCM-coding of video signals

In a dual port RAM having separate address controls, write/read paths and pre-loading circuits for each of the two input/output terminals, conflict situations are avoided when addressing a memory cell via the address controls of both input/outputs, through use of a clock circuit (20) which respectively alternately selects the address controls (8, 10, 9, 11) and the pre-loading circuits (16, 17) so that the address control (8, 10) for the first input/output (DEA1) and the pre-loading circuit (17) for the data lines (LP.sub.P2) allocated to the second input/output (DEA2) are activated during a first clock phase, and the address control (9, 11) of the second input/output (DEA2) and the data lines (LP.sub.P1) allocated to the first input/output (DEA1) are activated during a second clock phase.

Semiconductor memory with random access via two separate inputs/outputs

A circuit arrangement comprising a matrix-shaped memory for variable delay digital signals comprises a selection device for selecting columns of the memory, the selection device being switchable between two selected neighboring columns into which a portion of an external delay time setting data word is supplied for the selection of the columns. A dynamic switching by way of a supplied control signal is provided for switching between two neighboring columns. A setting and control device receives the full external delay time setting data word supplied thereto and generates a reset signal for the memory and a control signal for the selection device, and is supplied with an external reset signal by way of a reset input to directly reset the setting and control device and to indirectly reset the memory. The memory comprises a data input by way of which the data signal to be delayed can be input. The selection device comprises a data output by way of which the delayed data signals can be output. The selection device has data inputs connected to data outputs of the memory and the setting and control device is a data clock controlled device.

Circuit arrangement comprising a matrix-shaped memory arrangement for

A circuit arrangement comprises a matrix-shaped memory for variably adjustable delay of digital signals, whereby trigger elements in the form of two inverters fed back to one another are provided as storage elements, one of the two nodes thereof being connectible to a write bit line by way of a switching transistor controllable from a write word line and the other being connectible to a read bit line via a switching transistor controllable from a read word line. A row selector is clocked by the input data clock and is continuously settable and resettable at any time, the row selector comprising two signal outputs per selection stage which are offset in phase relative to one another, these respectively selecting one of the write word lines or read word lines which are provided per row of the matrix-shaped memory. Two separate bit lines, namely a write bit line and a read bit line are provided per column, these being respectively interconnected to all memory cells of a column. A disconnectible storage amplifier is provided per column, the input thereof being connected to the read bit line of the column assigned thereto and the output thereof being connected to the write bit line of the column following thereafter and serving as a data output. A data input for the data signals to be delayed is connected to the write bit line of the first column.

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Kirchheim, Germany

Hans J Mattausch