Rms to log converter circuit

Claim 2

A signal converter comprising, input means for supplying input signals, amplifier means for operating upon said input signals, squarer means connected to said amplifier means to square the signal produced thereby, averager means connected to said squarer means for averaging the signal produced by said squarer means, log converter means connected to said averager means to convert the signal produced thereby to an electrical signal which is a logarithmic representation thereof, and output means connected to said log converter means.

Claim 3

The signal converter recited in claim 1 wherein said amplifier means includes a plurality of amplification stages, and switching means connected to said averager means to vary the operation thereof.

Claim 4

The signal converter recited in claim 1 wherein said amplifier means exhibits variable gain, level sensor means associated with said amplifier means, gain switching means associated with said amplifier means, said level sensor means connected to said input means to detect the input signal supplied thereby and to produce an output signal in response to a predetermined condition at said input means, said output signal supplied by the level sensor means being supplied to said gain switching means to affect the gain of said amplifier means.

Claim 5

The signal generator recited in claim 3 including, logic means connected to said level sensor means, said logic means producing output signals indicative of the conditions of said level sensor means.

Claim 6

The signal generator recited in claim 1 including summing amplifier means connected to said log converter means, means supplying signals from said amplifier means to said summing amplifier means to affect the signal level supplied to said summing amplifier.

Claim 7

The signal generator recited in claim 1 wherein said input means includes attenuator means for operating upon input signals, and buffer amplifier means exhibiting high input impedance and low output impedance, said buffer amplifier connected to said attenuator means.

Claim 8

The signal generator recited in claim 3 wherein said level sensor means includes, differential connected amplifier means for receiving input signals, said differential connected amplifier means exhibitinG different conduction characteristics as a function of the level of the input signal supplied, rectifier bridge means connected to said differential amplifier means to conduct current therethrough as a function of the conduction characteristics exhibited by said differential connected amplifier, and switch means connected to said rectifier bridge means to be selectively rendered conductive as a function of the current conduction by said rectifier bridge means.

Claim 9

The signal generator recited in claim 7 wherein said gain switching means includes a plurality of switching devices connected in parallel with a fixed gain amplifier, each of said switching devices connected to said switch means to be selectively controlled thereby such that the gain of the amplifier means is varied as the feedback path in parallel with the fixed gain amplifier is varied by the selectively controlled operation of said switching devices.

Claim 10

The signal generator recited in claim 1 wherein said amplifier means includes, a plurality of stages of amplification, interconnection means in each of said stages except the last stage, said interconnection means arranged to maintain the succeeding stages relatively inoperative until the amplification factor thereof is required, said interconnection means being connected to and controlled by the level of said input signals.

Claim 11

The signal generator recited in claim 1 wherein said squarer means includes, a pair of field-effect transistors connected in parallel, means for connecting signals thereto from said amplifier means and further output means connected to said field-effect transistors, said field-effect transistors operative to produce a signal at said further output means which is proportional to the square of the signal from said amplifier means.

Claim 12

The signal generator recited in claim 1 wherein said averager means includes, filter means, voltage control means connected to said filter means to control the voltage supplied thereto, and switch means for controlling the portion of said filter means to which said voltage is supplied.

Claim 13

The signal generator recited in claim 11 including level sensor means for detecting the level of the input signal supplied by said input means, gating means for supplying output signals having one of two levels as a function of the level of said input signals, said gating means connected to said switch means to control the operation thereof as a function of the level of said output signal of said gating means.

Claim 14

The signal generator recited in claim 1 wherein said amplifier means exhibits variable gain, means for generating signals as a function of a change in the gain of said amplifier means, and gate means connected to said last named means for producing signals indicative of the number of gain changes which have occurred.