Nokia Technology Gmbh

Continental Automotive Gmbh

Friedbert Stuhlfelner

Harri Valio

A method for operating a serial non-volatile semiconductor memory in which, for safely writing data into the semiconductor memory, a serial write sequence is applied to an input terminal. The sequence is formed at least with a sequence of command bits, a sequence of address bits and a sequence of data bytes. During the transmission of the bits of the write sequence, a clock signal is present at a clock input and a sufficiently high supply voltage is present at a supply voltage terminal. On occurrence of a supply voltage that is too low, the write sequence and/or the clock signal is subsequently transmitted incorrectly during the transmission of the write sequence and of the clock signal to the semiconductor memory. In the alternative, the write sequence is not transmitted at all.

Method for operating a serial non-volatile semiconductor memory

In a new circuit arrangement for improving the signal-to-noise ratio, the entire audible frequency spectrum is divided into several abutting frequency channels. Each channel supplies the respective signal part in delayed form to an amplifier with controllable amplification. The amplifier's amplification is adjusted as a function of a comparator, so that when the audio frequency signal is below a threshold value during a specified time, the amplification of the controllable amplifier is gradually decreased to the lowest amplification value. Vice versa, when the useful signal again exceeds the threshold value, the amplification is gradually controlled upward to a maximum value.

Circuit arrangement for improving the signal-to-noise ratio

The invention introduces an arrangement which maintains the usefulness of a fader control (11) connected for example to an audio signal source (10), and at the same time considerably reduces the circuit cost. This is realized in that the distribution to different listening areas adjusted by the fader control (11) is determined from the audio signals that are present behind the fader control (11). To that end, first the audio output signals (L, R) are reconstructed in two adders (12.2, 12.3) and routed to a fourth adder (12.4). Two each audio signals (L.sub.V, R.sub.V) are routed to a first adder (12.1). The signals existing behind the adders (12.1/4) are then placed into a ratio with each other by a divider (20). From the quotient Q determined there, the distribution rate is then determined by a calculator (21) and made available to the multipliers (M1-4). Devices (17) to determine the average level value, followed by smoothing devices (18), which are positioned symmetrically with respect to the adders (12.1/4).

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Leiblfing, Germany

Friedbert Stuhlfelner