A decoding device is used to securely send corresponding data gathered from multiple underground sources to multiple users. The device comprises a signal receiving port connected to multiple bandwidth filters and further connected to internet access points that are assigned to end users for secure data access. The invention facilitates allowing the signal and data being transmitted through the formation of the earth to reach end users located nearby and significant distances away from the source of the transmission. A system and method utilizing the decoding device is provided.

A digital to analog converter (DAC) includes a plurality of DAC transistor devices having an input side configured to be selectively coupled to a system voltage based on a digital input signal and an output side configured to provide an analog output signal, a plurality of non-DAC transistor devices coupled to the input side of the DAC transistor devices, the non-DAC transistor devices configured as variable resistances, and a control circuit configured to adjust a bias of the non-DAC transistor devices.

A digital to analog converter (DAC) includes a plurality of DAC transistor devices having an input side configured to be selectively coupled to a system voltage based on a digital input signal and an output side configured to provide an analog output signal, a plurality of non-DAC transistor devices coupled to the input side of the DAC transistor devices, the non-DAC transistor devices configured as variable resistances, and a control circuit configured to adjust a bias of the non-DAC transistor devices.

A signal processing circuit including a plurality of analog-to-digital conversion circuits, an in-memory computing device, and a control method thereof are provided. Each analog-to-digital conversion circuit includes a reset switch, a capacitor array circuit, a voltage comparator, and a successive approximation circuit. A first terminal of the reset switch receives a first reference voltage, and a second terminal of the reset switch receives an input voltage signal. The capacitor array circuit adjusts the input voltage signal according to a successive approximation control signal to generate an adjusted voltage. The voltage comparator compares the voltage levels of the adjusted voltage and a second reference voltage to generate a comparison signal. The successive approximation circuit generates a successive approximation control signal according to the comparison signal and generates an output digital signal corresponding to the input voltage signal. The capacitor array circuit maintains the input voltage signal during a non-reset stage.

An analog signal buffer is disclosed. The analog signal buffer may include a transconductance cell and an active load. The active load may load the current from the transconductance cell with a PMOS transistor and an NMOS transistor and provide a feedback resistance. A transimpedance amplifier is disclosed. The transimpedance amplifier may include a first cell configured to receive a first signal and output a second signal and a second cell coupled to the first cell. The second cell may include an active feedback structure configured to couple an output of the second cell to an input of the second cell.

An analog signal buffer is disclosed. The analog signal buffer may include a transconductance cell and an active load. The active load may load the current from the transconductance cell with a PMOS transistor and an NMOS transistor and provide a feedback resistance. A transimpedance amplifier is disclosed. The transimpedance amplifier may include a first cell configured to receive a first signal and output a second signal and a second cell coupled to the first cell. The second cell may include an active feedback structure configured to couple an output of the second cell to an input of the second cell.

A compensator is described with higher bandwidth than a traditional differential compensator, lower area than traditional differential compensator (e.g., 40% lower area), and lower power than traditional differential compensator. The compensator includes a differential to single-ended circuitry that reduces the number of passive devices used to compensate an input signal. The high bandwidth compensator allows for faster power state and/or voltage transitions. For example, a pre-charge technique is applied to handle faster power state transitions that enables aggressive dynamic voltage and frequency scaling (DVFS) and voltage transitions. The compensator is configurable in that it can operate in voltage mode or current mode.

An over/under voltage protection circuit includes a voltage input terminal, a digital-to analog converter, a comparator, and a control circuit. The comparator includes a first input coupled to an output of the digital-to-analog converter, and a second input coupled to the voltage input terminal. The control circuit includes an output coupled to an input of the digital-to-analog converter, and an input coupled to an output of the comparator. The control circuit is configured to set the digital-to-analog converter to generate an overvoltage fault threshold responsive to the output of the comparator indicating that voltage of a signal at the voltage input terminal exceeds a threshold currently generated by the digital-to-analog converter.

A digital-to-analog conversion circuit (60) for converting a digital input sequence to an analog representation is disclosed. It comprises a first DAC, (100) wherein the first DAC (100) is of a capacitive voltage division type having a capacitive load (110). Furthermore, it comprises a second DAC (120) having a resistive load (130). An output (104) of the first DAC (100) and an output (124) of the second DAC (120) are connected, such that said capacitive load (110) and said resistive load (130) are connected in parallel.

Described herein are apparatus and methods for digitally enhancing digital-to-analog converter (DAC) resolution. A digitally enhanced DAC includes a decoder circuit configured to convert a N-bit input data to at least N code bits, a digital enhancement circuit configured to logically operate on a least significant bit (LSB) of the N-bit data, and a switching network including at least N DAC unit elements, where a least significant DAC unit element is controlled by the digital enhancement circuit to output a factored nominal current or voltage when a logical operation outputs a defined logic level for the LSB and to output a nominal current or voltage absent output of the defined logic level and a remaining DAC unit elements are controlled by a remaining code bits of the at least N code bits. This provides a N+1 bit resolution for the DAC without increasing the at least N DAC unit elements.