Circuit for controlling a ration meter

A circuit for controlling a ratio meter, wherein said circuit comprises:

• means for generating a digital signal representative of a parameter to be displayed;
• memory means for providing a pre-defined sine or cosine function to encode the digital signal, the memory means being addressed by intermediate significant bits of the digital signal;
• interpolation means using the least significant bits of the digital signal to correct the encoded signal from the memory means;
• and
• at least two register means being periodically loaded at a period TRC by sine and cosine function signals provided respectively from the interpolation means, the two register means being decremented at a fixed frequency Fdec, outputs from each of the two register means changing level when the respective contents of the two register means reach zero, said outputs serving to control power stage feeding coils of said ratio meter, wherein (2.sup.M).times.1/(Fdec)=TRC in which M represents the number of bits in the function signal loaded into each register means.

A circuit for controlling a ratio meter, wherein said circuit comprises:

• means for generating a digital signal representative of a parameter to be displayed;
• memory means for providing a pre-defined tangent function to encode the digital signal, the memory means being addressed by intermediate significant bits of the digital signal;
• interpolation means using the least significant bits of the digital signal to correct the encoded signal from the memory means;
• and
• at least one register means being periodically loaded at the period TRC by tangent function signals provided from the interpolation means, the register means being decremented at a fixed frequency Fdec, output from the register means changing level when the contents of the register means reach zero, said output serving to control power stage feeding coils of said ratio meter, wherein (2.sup.M).times.1/(Fdec)=TRC in which M represents the number of bits in the function signal loaded into each register means.

A circuit for controlling a ratio meter, wherein said circuit comprises:

• a counter means for receiving a clock signal (Fe) at a fixed frequency at its clock input, and a signal whose frequency is related to the frequency of an input signal representing a parameter to be displayed at its control input, the counter means counting clock pulses during the period the signal is being provided to its control input;
• a divider means for dividing a programmable constant E(e) by a signal output from the counter means so as to provide a digital signal at the output of the divider means which is representative of the frequency of the input signal;
• memory means for providing a pre-defined sine, cosine or tangent function to encode the digital signal, the memory means being addressed by intermediate significant bits of the digital signal;
• and
• interpolation means using the least significant bits of the digital signal to correct the signal output from the memory means, said corrected signal used to control said ratio meter.

A circuit for controlling a ratio meter, comprising:

• means for generating digital signals representative of parameters to be displayed;
• a module responsive to a slope of the digital signals, said module being a hysteresis module that takes no account of changes in the values of the digital signals unless these changes exceed a determined threshold;
• memory means using a pre-defined sine, cosine or tangent function to encode the digital signals output from said module, the memory means being addressed by respective intermediate significant bits of the digital signals;
• and
• interpolation means using the respective least significant bits of the digital signals to correct the encoded signals from the memory means, said corrected encoded signals used to control said ratio meter.

A circuit for controlling a ratio meter, wherein the circuit comprises:

• means for generating digital signals representative of parameters to be displayed;
• a first module for obtaining a sliding mean of K samples from said digital signal;
• a second module responsive to a slope interpolated from the digital signals provided from said first module to limit the slope of the digital signals provided at its output;
• memory means using a pre-defined sine, cosine or tangent function to respectively encode each of the digital signals output from the second module, the memory means being addressed by respective intermediate significant bits of the digital signals;
• and
• interpolation means using the respective least significant bits of the digital signals to correct the encoded signals output from the memory means, said corrected encoded signals used to control said ratio meter.