Abstract: In an input signal power dynamic range compressing circuit, an input signal is distributed by a directional coupler to a linear signal transfer path and a compressing signal generating path, and in the compressing signal generating path a compressing signal, which keeps the peak-to-average-power ratio of the input signal below a predetermined value, is generated from the input signal. The compressing signal is combined by a power combiner with the input signal having passed through the linear signal transfer path.

Abstract: Apparatus and method that mitigate the noise incurred on a wireless communications path between an encoder and a decoder of a wireless audio noise reduction system that utilizes frequency modulation (FM). The encoder includes a variable compressor that invokes compression whenever the input signal is above a first threshold level. The decoder includes a variable expander that invokes expansion whenever the received signal from the decoder is above a second threshold.

Abstract: Compander architecture and method for ensuring that the components of an output signal are synchronized includes calculating a gain calculation for an input signal, detecting a predetermined condition such as a zero crossing or absence of a zero crossing within a specified period, and ensuring that the result of the gain calculation is providing to the system synchronously with the input signal. The input signal may be divided into one or more signals for processing, and the gain calculation may include one or more power estimations and one or more gain cells associated with the multiple signals, and may further include variable attack and release.

Abstract: In a dynamics compressor, an analog signal to be compressed is supplied to a first amplifier stage as an input signal, and the output signal thereof is supplied to the next amplifier stage as an input signal, and so on for a number of successive amplifier stages. Each amplifier stage amplifies its input signal with a stage amplification until it reaches a stage limit level. The analog signal and the respective output signals of the amplifier stages are summed in a summation stage to form a sum signal. Above a minimal level, the magnitude of the curve of the sum signal roughly corresponds to an exponent characteristic of the magnitude of the analog signal.

Abstract: Method and apparatus are provided for processing a wide dynamic range analog signal which comprises a compressive nonlinear transfer function responsive to the average amplitude of the signal without feedback along the signal path. The invention employs frequency selective filtering and expansion of the compressed signal. The invention is applicable to any analog signal system having a plurality of channels carrying related signal information.

Abstract: A companding amplifier wherein compression data is provided to an expansion circuit along with audio data. An analog audio input signal is compressed and converted into digital data by a compression circuit. The compression circuit includes a data framer that produces a digital data stream that contains both the digital audio data and digital compression data. The resultant digital data stream can then be recorded on a medium such as a CD or DAT, or transmitted over a medium such as wire, fiber optic or radio waves. The digital data stream can then be read back or otherwise received by an expansion circuit that includes a data separator that separates the digital audio data and digital compression data. The digital audio data is then converted back to an analog audio signal, and the digital compression data is converted to an analog control signal that is used as the control signal for expansion.

Abstract: An apparatus and method for compressing and expanding an information signal for use in noise reduction which includes an input terminal to receive the information signal, a first frequency crossover circuit coupled to the input terminal and configured to divide the information signal into a first and second frequency band. A second frequency crossover circuit coupled with the first crossover circuit configured to receive at least a portion of the information signal within the first frequency band and to further divide the information signal into a third and fourth frequency band. A third frequency crossover circuit coupled with the first crossover circuit configured to receive at least a portion of the information signal within the second frequency band and to divide the information signal into a fifth and sixth frequency band.

Abstract: The present invention is a digital dynamic compression or automatic gain control (AGC) (10) adapted for use in high quality audio and hearing aids applications. An efficient digital AGC design employs two compact ROM-based tables (ROM_CSD, ROM_SPL) in addition to two comparators (COMP_A, COMP_B) and several registers (REG_A, REG_B, ADDR_A, ADDR_B). While one ROM stores the values of discrete input signal levels, the other contains gain codes based on a canonical signed digit (CSD) coding approach that leads to a very simple gain multiplier (20). In many cases an extremely compact table for gain values can be achieved by reusing a single small-size ROM that behaves like one that is several time larger. Two design examples are shown to expound the insights of the new digital AGC design. For the less-than-half-dB-gain-step cases only two adders are required for the multiplier whereas just three adders are needed in the situations with less than quarter-dB gain steps.

Abstract: A variable signal attenuating circuit which has a function of preventing dropout of an attenuated signal even if a large attenuation value is set. A dynamic range compression processing unit is provided in an input unit of the variable signal attenuating circuit for compressing the dynamic range of an input signal within a predetermined range in accordance with a set attenuation value, such that the signal passing through the compression processing unit is attenuated by the set attenuation value.

Abstract: Output control system and method includes calculating gain for an input signal, detecting a predetermined condition, and modifying the gain calculation in accordance with one or more kneepoints to provide a varying output signal. A companding ratio is then established in accordance with the kneepoints.

Abstract: Variable attack and release system and method are disclosed for dynamically modifying the various elements of the system including modifying compander response time to dynamically adjust for changing parameters such as environmental or input signal changes to maintain output signals within predetermined limits. The system and method include permitting accurate and quick response to noise sources having a duration which exceeds a predetermined threshold while at the same time ignoring transient or short duration environmental noise.

Abstract: Generally, the invention relates to a method and apparatus to improve the performance of multi-stage radio frequency linear power amplifiers. More particularly, the present invention discloses a cascaded gain expansion stage and gain compression stage at differing bias levels to produce an amplifier with superior linearity and lower intermodulation distortion and adjacent channel power than any single stage by alone.

Abstract: The present invention is directed to a circuit for performing volume expansion on an audio signal. The circuit includes an amplifier that has an input side and an output side. Further, the amplifier amplifies the audio signal at a first amplification to produce an amplified signal at the output side of the amplifier. The circuit also includes a shunting element coupled across the input side and output side of the amplifier. The shunting element includes a variable impedance device for changing the first amplification of the amplifier to a second amplification if the amplified signal reaches a predetermined threshold.

Abstract: In an input signal power dynamic range compressing circuit, an input signal is distributed by a directional coupler to a linear signal transfer path and a compressing signal generating path, and in the compressing signal generating path a compressing signal, which keeps the peak-to-average-power ratio of the input signal below a predetermined value, is generated from the input signal. The compressing signal is combined by a power combiner with the input signal having passed through the linear signal transfer path.

Abstract: The present invention relates to a signal compressing circuit which amplifies an input signal on a logarithmic scale in an appropriate range, and has a variable gain stage, an input signal detector, and an automatic level controlling circuit, the automatic level controlling circuit including: a first comparator for comparing the input signal to a first reference voltage, and generating a signal proportional to the difference between them; a second comparator for comparing the input signal to a second reference voltage, and generating a signal proportional to the difference between them; and a current mirror for generating a controlling current in proportion to the output signal of the first and second comparators, thus controlling the gain of the variable gain stage in two steps so as to generate stable output signals.

Abstract: An automatic dynamic range control circuit is provided with a fixed-gain first circuit means and a variable-gain second circuit means having substantially the same propagation delay as the first circuit means. The automatic dynamic range control circuit holds the peak value of an input signal, selects the first circuit means when this peak value is smaller than a reference signal level, and selects the second circuit means when the peak value exceeds this reference signal level. When the held peak value is smaller than the reference signal level, the second circuit means is operated at the same gain relative to an input signal as the first circuit means by having its gain set by the reference signal. When the held peak value exceeds the reference signal, the gain of the second circuit means is limited by this held peak value and its output level is kept at or below a prescribed level.

Abstract: In an amplifier circuit having an amplifier path, a new pre-distortion arrangement is provided. The amplifier circuit includes a signal source, an intermediate amplifier stage, and a power amplifier stage connected sequentially, in series along the amplifier path. The power amplifier stage includes one or more amplifiers operationally connected in parallel, and one or more pre-correction circuits. Each of the amplifiers subjecting an inputted signal to shifts away from their intended values. Each of the pre-correction circuits is associated with one of the amplifiers and connected between an output of the intermediate amplifier stage and the associated amplifier. Each of the pre-correction circuits pre-distorts the signal input to the associated amplifier to compensate for the distortion caused by the associated amplifier.

Abstract: An amplifier with programmable gain and input linearity at high frequency allows an increase in the gain without effecting input linearity and without significantly increasing current consumption. The amplifier includes an input stage which receives a voltage signal for performing a current conversion thereof with compression. An output stage is connected to the input stage and decompresses the signal provided by the input stage for producing gain amplification thereof. The amplifier further includes at least one current amplifier stage interposed between the input stage and the output stage. The at least one current amplifier includes at least one bipolar transistor series-connected to a load diode and to a current source. A reduction in the transconductance of the load diode is provided in the at least one amplifier stage to determine a programmable gain factor for the amplifier.

Abstract: A level detector detects an input signal level. A rectifier (210) receives the input signal and provides a rectified signal. A prefilter (220) receives the rectified signal and attenuates high frequency components at frequencies near multiples of a decimation sample rate. The prefiltered signal is decimated (230) and low pass filtered by a lowpass filter (240) having a passband below the input frequency of the input signal. The level detector can be provided to control a variable gain stage circuit (935, 1010) which applies a gain to the input signal based on the level to form a dynamic range compressor or expander.

Abstract: Digital audio processing apparatus for applying a time-varying gain to an input digital audio signal over contiguous first, second and third time periods, in which: the applied gain changes at no more than a first maximum rate of change during the first time period; the applied gain changes at no more than a second maximum rate of change during the third time period; and during the second time period the rate of change of the applied gain varies monotonically from a substantially zero rate of change towards the second maximum rate of change.

Abstract: An audio level dynamic range compression circuit 1 comprises a variable gain amplifier 6, an audio signal level averaging stage 8, an analog-to-digital converter 10, and a digital processor 12. The output from the averaging stage 8 is passed to the analog-to-digital converter 10 which has as its output a digital value representative of the level of the averaged audio signal. This digital value is then passed to the digital processor 12 which processes the digital value relative to a predetermined level of the averaged audio signal to produce a gain control output which varies in response to the digital value and which is passed to the variable gain amplifier 6 in order to compress the dynamic range of the output audio signal when the digital value is above the predetermined level. The gain control output is more rapid when the level of the averaged audio signal is rising than when the level of the averaged audio signal is falling.

Abstract: An amplifier uses gain compression techniques to provide linear gain control over a wide dynamic range, and includes an amplifier having input and output legs, a gain controller coupled between the input and output legs of the amplifier, a gain control circuit having an input coupled to the amplifier output leg and output coupled to the gain controller. The gain controller is responsive to a gain control signal to permit continuous gain adjustment of the amplifier. The gain control circuit is configured to compare an output voltage on the amplifier output leg with a predetermined threshold voltage and to generate a gain control signal on the gain control circuit output so as to provide continuous gain adjustment of the amplifier at least when the amplifier output voltage is greater than the threshold voltage. A hearing aid using a single compression amplifier or multiple compression amplifiers to minimize sound distortion and enhance user comfort is also provided.

Abstract: A bit-serial digital expandor includes a bit-serial dual scaler block (340), a bit-serial rectifier block (320), a bit-serial lowpass wave digital filter block (350), a bit-serial scaler with overflow detection block (360), a bit-serial multiplier block (380), and a bit-serial scaler and clipper block (395). This bit-serial expandor can be used in an AMPS cellular telephone receiver to produce a receiver having a lower silicon area, gate count, and current drain compared to equivalent parallel architecture receivers.

Abstract: In a mobile telephone device, the audio compressor (21) performs amplitude compression by giving a less variable gain to an input audio signal which is of a lower level range than it does for an input audio signal which is of a higher level range. Alternatively, an adder (17) calculates a sum of (a) an audio signal comprising a talk signal component and a noise component, and (b) a generated signal having an out-of audio frequency, as 6 kHz, and a predetermined level and supplies the compressor (21) with the sum as its input signal. A compressed signal is transmitted to a base station as a radio signal and is expanded.

Abstract: An audio peak limiter suitable for use between a compressor and pre-emphasis circuit. The limiter uses a center clipper to develop a control signal for a 1/x control law VCA. The center clipping, after rectification, is sampled-and-held for 4 milliseconds by a retriggerable sample-and-hold circuit then low-pass filtered. The compressed audio is delayed for 4 milliseconds before being coupled to the VCA. The VCA acts as a modulator to provide control of its peak output level while simultaneously limiting the bandwidth of the modulation sidebands caused by the modulation process, so that these sidebands are better masked psychoacoustically than sidebands that would be caused by simple clipping of the compressed audio.

Abstract: First and second analogue signal processing circuit has first to fourth input terminals and first and second output terminals, and functions such that the first and second output terminals have an equal potential and that a difference between output currents of the first and second output terminals is proportional to a product obtained by multiplying a potential difference between the first and second input terminals by a potential difference between the third and fourth input terminals. The first input terminal of the first analogue signal processing circuit is supplied with an input signal, and the second input terminal is supplied with ground potential. The third input terminal is supplied with a second reference potential, and the fourth input terminal is supplied with a third reference potential. The first input terminal of the second analogue signal processing circuit is supplied with an output signal from an operational amplifier, and the second input terminal is supplied with the ground potential.

Abstract: A multipoint communication apparatus receives a set of audio signals encoded by gain-shape vector quantization. A gain detector in the multipoint communication apparatus dynamically selects a subset of these audio signals on the basis of gain indices contained in the audio signals. Only the selected subset of audio signals are decoded. The decoded signals are combined to produce an audio output signal.

Abstract: An audio processor (10) that is specifically designed to be included in combination with an audio recording system or a movie theater sound system. The processor (10) consists of two major circuits, a single-ended, limited compressor/expander circuit (12) and an output circuit (205) that incorporates a dynamic noise reduction (DNR) circuit (206). A single adjustment sets the trip points for both the low-level and high-level operating mode of the compressor/expander circuit (12). Likewise, a single adjustment sets the bandwidth of the DNR circuit (206). When the processor is in the expand mode, the two circuits (12,206) complement each other such that when the low-level expander lowers the signal level, the source noise is also reduced. The reduced signal results in an earlier activation of the DNR circuit (206) bandwidth control which reduces its bandwidth resulting in a further reduction of the noise level.

Abstract: A compander circuit includes first and second volume controllers, a comparator, a counter and a control part. The comparator compares a compared voltage with a rectified and smoothed signal of an input signal of the compander circuit or an output signal of the first volume controller receiving the input signal, the compared voltage being an output signal of the second volume controller. The counter executes a count operation on an output signal of the comparator in synchronism with a clock signal and controls gains of the first and second volume controllers on the basis of a counter value of the counter. The control part controls a frequency of the clock signal applied to the counter by a predetermined control signal.

Abstract: A signal-processing circuit adapted for signal compression and expansion performed in the transmitter and receiver of mobile communication equipment. The signal-processing circuit comprises a multiplication type D/A converter to which an analog signal is applied, a level detector circuit that detects the level of the analog signal, and an A/D converter. The D/A converter converts the analog input signal into an analog output signal having an amplitude corresponding to digital control data. The A/D converter digitizes the output signal from the level detector circuit and supplies it as said digital control data to the D/A converter. These circuits can be fabricated from CMOS circuits.

Abstract: A signal conditioning circuit compresses an audio signal by producing a gain signal that is a function of the time-averaged audio signal and a compression ratio, and amplifying the audio signal by an exponential function of the gain signal. The conditioning circuit merges the functions of buffering the audio signal and producing a full-wave rectified version of the audio signal into a single buffer circuit. An averaging circuit generates a time-averaged signal in response to the full-wave rectified signal. An interface circuit includes downward expansion, compression and limiting circuits for scaling the time-averaged signal with a low compression ratio when it is less than a break point, with a selected compression ratio when it is between the break point and a rotation point, and with a high compression ratio when it exceeds the rotation point. The interface circuit produces the gain signal in response to the time-averaged signal and the corresponding compression ratio.

Abstract: An analog tape saturation simulator produces the same results as analog tape saturation in a controllable environment which can be user adjusted to the desirable level of saturation effect. A log-based audio detector receives the audio signal in front of a circuit limiting the maximum range over which a dynamic filter will operate to control the high frequency bandwidth via a voltage-controlled low pass filter which follows a soft-clipping distortion circuit also receiving the audio signal. The simulator provides dynamic changes to the signal based on the level of simulated saturation taking place. The simulator produces the nonlinear, soft clipping characteristics of overdriving analog tape and dynamically reduces the high frequency information in response to the input amplitude of the audio signal.

Abstract: Frequency characteristic shaping circuitry having a plurality of bandpass filters to which an audio signal is supplied and a plurality of variable gain attenuators individually associated with the bandpass filters. The output signals of the variable gain attenuators are supplied to a pair of summing circuits, one providing a sum of the attenuator output signals and the other providing an inverted version of the sum of the attenuator output signals. The sum of the attenuator output signals and the inverted version of the sum of the attenuator output signals are combined in a final summing circuit. In another aspect of the present invention, each bandpass filter has a second variable gain attenuator and the output signals of these attenuators are supplied to another pair of summing circuits, one providing a sum of these attenuator output signals and the other providing an inverted version of the sum of these attenuator output signals.

Abstract: An electronic audio processing system for insertion into the line prior to power amplification and a related method are disclosed which component and method render a frequency response in which undesirably strong frequency bands are flattened relative to the total frequency response by up to 10 dB, thereby providing enhanced dynamic audio reproduction. The audio signal is split into a plurality of frequency bands, each of which is actively, dynamically limited to a predetermined level related to the overall level of the unprocessed signal. The frequency bands are then recombined into a single processed signal which has an overall response which is as much as 10 dB more linearity than the unprocessed signal.

Abstract: At least two information waveforms are transmitted over the same communications channel using Lincompex techniques. Each of the information waveforms are modulated using Lincompex techniques to generate compressed information waveforms and associated control tones. The compressed information waveforms have the same frequency band. The compressed information waveforms and associated control tones are arithmetically combined, and transmitted over a transmission medium. These signals are then received from the transmission medium. A plurality of Lincompex expanders demodulate the received signals using Lincompex techniques and one of the associated control tones.

Abstract: A signal processing circuit includes two analog signal processors, an operational amplifier, a rectifier, and a reference potential generator. Each analog signal processor has four input terminals and two output terminals, and is designed to operate such that the first and second output terminals are set at the same potential and that a current difference between the first and second output terminals is proportional to a product of a potential difference between the first and second input terminal and a potential difference between the third and fourth input terminal. The first, second, third and fourth input terminals of the first analog signal processor are connected to receive an input signal, a first reference potential, a second reference potential, and a third reference potential, respectively. The output terminals of the first analog signal processor are connected to the negative and positive input terminals of the operational amplifier, respectively.

Abstract: An audio compressor using interactive layered time constants to create an easy to use compressor which self adapts to the program characteristics and provides a desirable and pleasing effect over a wide range of audio program material. The audio compressor includes an adaptable filter connected between an output signal path and a control feedback signal path of a voltage control amplifier. The adaptable filter comprises a first resistor-capacitor circuit connected to the output signal path and producing a charging/discharging voltage which is more dependent on a transient peak value of the audio signals and a second resistor-capacitor circuit working under the charging/discharging voltage of the first resistor/capacitor circuit for producing a charging/discharging voltage which is more dependent on an average value of the audio signals.

Abstract: An audio signal has its dynamic range compressed by a system which first samples a block of the audio signal (10), typically several seconds long. The level of the signal in this block is analyzed (12, 14) and an ideal signal level is calculated for the block (16, 18, 20). A gain control signal is then derived which adjusts the gain applied to that block towards that required to give the calculated ideal signal level.

Abstract: A peak accelerated compressor comprising a voltage controlled amplifier, a level detector and a peak accelerated filter circuit. The voltage controlled amplifier circuit is utilized for processing an input audio signal and producing an output audio signal. The level detector circuit is utilized for processing a sample audio signal which contains transient peaks and average waveforms. The peak accelerated filter circuit is coupled between the level detector circuit and the voltage controlled amplifier circuit for producing a control output signal to change the gain of the voltage controlled amplifier circuit in response to the transient peaks in the sample audio signal. The peak accelerated compressor effectively enhances the compression for transient peaks without adversely affecting the normal compression of average waveforms.

Abstract: One-bit analog-to-digital converters (ADCs) and digital-analog-converters (DACs) employ an adaptive filter. The filter has two regimes of operation: variable gain within the passband of the filter under low-level signal conditions and fixed gain but a variable filter cutoff frequency (sliding band) under high-level signal conditions. Thus, excessive low-frequency gain under no-signal conditions is avoided and, when implemented using a voltage controlled amplifier (VCA), the arrangement does not demand less offset from the VCA under low-level signal conditions.

Abstract: An audio compressor having both a feedback compressor and a feedforward compressor. The feedback compressor operates so as to provide envelope detection. A sidechain processor which receives an input from the feedback path includes a non-linear low-pass filter and a non-linear amplifier. The output of this processor provides the gain-control signal for the feedforward compressor. The main audio path is through the feedforward compressor.

Abstract: A signal processing circuit for an audio apparatus has a variable gain amplifier whose gain is varied in accordance with a gain controlling signal supplied thereto. The signal processing circuit comprises a gain setting section having a plurality of tables of input-output characteristics according to a level of loudness selected by a user. The characteristics being for the variable gain amplifier. A table selecting section selects a corresponding one of the plurality of input-output characteristics in accordance with the selected level of loudness. The table selecting section supplies the corresponding input-output characteristic to the variable gain amplifier so as to set the variable gain amplifier for a gain corresponding to the input-output characteristic.

Abstract: A radio receiver for an RF signal which is phase or frequency modulated by an information signal. The receiver has an analog receiving section which provides non-linear dynamic compression. The resulting analog signal is sampled and the samples are digitized by an A/D converter. The non-linear dynamic compression reduces the necessary number of quantizing steps in the A/D converter, which is less expensive, but thereby introduces non-linear distortion. To compensate such distortion, in the digital processing section of the receiver an expansion section is provided which processes the digital signal samples in accordance with the inverse of the non-linear dynamic compression characteristic. The resulting expanded digital sample values equalize the analog non-linear dynamic compression. The information signal is recovered from the expanded digital signals.

Abstract: An audio frequency compressing system for amplifying an input signal to produce a power output signal while removing high-level signals which could harm a listener. Gain control in the feedback path of an amplifier includes both a gain controller circuit for supplying a constant feedback impedance and a plurality of resistors which can be coupled to the gain controller circuit to increase or decrease the feedback impedance. Coupling of the resistors to the gain controller circuit is controlled by a feedback control circuit having both an automatic gain control circuit and a continuous high-level protection circuit.

Abstract: A synchronous progressive-compression type logarithmic amplifier includes one or two channels of amplifier/limiter stages and a corresponding multi-stage synchronous demodulator circuit to provide low noise and/or low power operation as well as other useful operational modes. A preferred embodiment of the invention includes two channels in which the input of a first amplifier stage in each channel forms a logarithmic amplifier input. The synchronous demodulator circuit is realized as a number of multiplier stages each having a first input coupled to the output of a corresponding amplifier stage in the first channel, a second input coupled to the output of a corresponding amplifier stage in the second channel, and a current output. A current summing bus is coupled to the current outputs of each of the multiplier stages, and forms the logarithmic amplifier output.

Abstract: The invention relates to a compressor and an expander for use in a compander realized in CMOS-technology which is used to improve speech quality in mobile phone systems AMPS (NAMPS), NMT and TACS (JTACS, ETACS, NTACS). The compander is integrated with other functions of the mobile phone. The compressor and expander have SC-amplifiers controlled by a control logic. A double comparator XOR-block is used in the control of the amplifiers.

Abstract: An improved audio compressor of the type which is useful in a hearing aid and having a programmable compression ratio is disclosed. In the preferred embodiment, the compressor is used in a hearing aid device of the type which comprises a bandsplit filter to divide an input audio signal into a plurality of frequency bands. Associated with each frequency band is a limiter means which provides variable gain amplification of the input signal as a function of the amplitude of the input signal and as a further function of a programmable control signal. A feedforward means is disposed in parallel to the limiter means, said feedforward means providing a fixed gain signal. The output of the limiter means and the feedforward means are combined at a summing node which forms the input to a variable gain amplifier. Associated control circuitry allows the limiter gain to be programmed to meet the needs of an individual user. The compressor has a variable compression ratio in the form of a sigmoid function.

Abstract: A signal processing circuit in an audio device includes a variable gain control section for providing a variable amplification gain to an input signal in response to a gain control signal, an input signal level detecting section for detecting a level of the input signal and for generating a corresponding detection signal, and a time constant setting section for storing a plurality of time constant tables. Each one of the plurality of time constant tables includes a set of input signal delay characteristics corresponding to a predetermined level of the input signal. A time constant selecting section selects one of the plurality of time constant tables in the time constant setting section in response to the detection signal. The gain control signal is determined by the selected one of the plurality of time constant tables and the amplification gain of the variable gain control section is varied according to the selected one of the plurality of time constant tables.

Abstract: A compandor circuit uses a DC-coupled compressor to reduce the required IC package size to 8-pins. A delta gain stage and rectifier in the feedback path of the compressor circuit receive the AC and DC components of the compressed analog output signal Features of the delta gain stage and rectifier eliminate the need for any AC-coupling capacitors in the feedback path thereby reducing the number of external components The remaining external components may be made smaller and manufactured as surface mount devices An expandor circuit receives a second compressed analog signal and expands it to full amplitude dynamic range.

Abstract: A low power, wide-dynamic-range, signal compressor is suitable for operat from batteries. The compressor input is compatable with most sensors, resistive, capacitive or inductive and it is capable of compressing 150 db of input dynamic range into a 6 bit digital or 40 db analog signal. The output from the compressor is single valued and satisfactory for driving standard telemetry equipment.