Signal measurement

Claim 1

Signal measurement apparatus comprising: means for applying gain to an input signal to produce a resulting signal having a gained signal level; means for comparing the resulting signal with a known reference signal having a reference level and for producing an output indicative of the difference between them; and a feedback loop for altering the gain applied to the input signal, the feedback loop including (a) a counter receiving the output of the comparing means adapted to count up or down when the gained signal level is respectively lower or higher than the reference level and (b) a memory element for storing data indicative of values of a chosen transfer function, wherein a value is selected from the memory element according to the current count of the counter and the gain is altered by an amount related to the selected value; the apparatus being adapted to provide an output signal indicative of the count of the counter.

Claim 9

A method of signal measurement comprising the steps of: (a) applying gain to an input signal to produce a resulting signal having a gained signal level; (b) clocking a counter to count up or down if the gained signal level is respectively lower or higher than a known reference signal level to produce a count value; (c) using the count value to select a chosen value from a plurality of values indicative of a chosen transfer function stored in a memory element and applying the chosen value as a negative feedback signal to alter the gain; (d) repeating steps (a)-(c) until an equilibrium state is reached at which the gained signal level is substantially equal to the known reference signal level; and (e) deriving a value for the gained signal level of the input signal from the count value produced by the counter.

Claim 10

A method of signal measurement comprising the steps of: (a) applying gain to an input signal to produce a resulting signal having a gained signal level; (b) clocking a counter to count up or down if the gained signal level is respectively lower or higher than a known reference signal level to produce a count value; (c) using the count value to select a chosen value from a plurality of values indicative of a chosen transfer function stored in a memory element and applying the chosen value as a negative feedback signal to alter the gain; (d) repeating steps (a)-(c) until an equilibrium state is reached at which the gained signal level is substantially equal to the known reference signal level; and (e) deriving a value for the gained signal level of the input signal from the count value produced by the counter.