Abstract: In some embodiments, an electric field generator generates an electric field at a nominal frequency and a nominal amplitude. The electric field generator is connected to an antenna that radiates the electric field. A detector measures a frequency and an amplitude of the generated electric field as the electric field interacts with a body (such as a human body) in a reactive near-field region of the electric field. For each of one or more internal components of the body, a computation unit determines a respective periodic behavior in the measured frequency corresponding to movement of the internal component. The computation unit also computes, for each of the one or more internal components, a respective rate of the movement of the internal component based on the determined respective periodic behavior in the measured frequency. A gain control circuit adjusts the nominal amplitude according to the measured amplitude.

Abstract: In some embodiments, an electric field generator includes a differential oscillator that oscillates at a nominal frequency. The electric field generator is connected to a differential antenna that radiates an electric field. A differential detector measures a frequency of the generated electric field as the electric field interacts with a body (such as a human body) in a reactive near-field region of the electric field. For each of one or more internal components of the body, a computation unit determines a respective periodic behavior in the measured frequency indicative of movement of the internal component. The computation unit also computes, for each of the one or more internal components of the body, a respective rate of movement (such as a heart rate or a respiration rate) of the internal component according to the respective periodic behavior in the measured frequency.

Abstract: In some embodiments, an electric field generator generates an electric field at a nominal frequency. A detector measures, at multiple time points during a measuring period, one or more properties of the generated electric field. In various embodiments, the one or more properties of the electric field change over time due to interactions with a human body in a reactive near-field region of the electric field. From the measured one or more properties, a computation unit determines one or more periodic behaviors (such as a respiration or heartbeat) and one or more non-periodic behaviors (such as movement of a limb). The computation unit also computes, from at least one of the periodic and non-periodic behaviors, one or more physiological parameters of the human body. From the one or more physiological parameters, the computation unit detects one or more symptoms of a condition of the human body.

Abstract: A transmission system includes transmit and receive paths coupled via a hybrid circuit to a bidirectional transmission path. The transmit path includes a digital-to-analog converter (DAC) having a given range and precision. The transmit path signal is limited and truncated to this range and precision before the DAC. In one arrangement including an echo canceller coupled between the transmit and receive paths, a difference of the transmit path signal before and after limiting and truncation is used to produce an estimated echo response which is subtracted from the receive path signal. In another arrangement, all of the inputs to the echo canceller are derived from the transmit path after the limiting and truncation. Instead, or in addition, the amplitudes of transmit path signal samples can be shaped in conjunction with the limiting. The system can in particular be an ADSL transmission system using multicarrier modulation.