An electrical filter structure for forwarding an electrical signal from a first port to a second port in a frequency selective manner, wherein the filter is an edge-coupled filter, the filter comprising: a plurality of coupled line sections coupled in a series, comprising at least a first coupled line section and a last coupled line section; wherein the first port is connected with the first of the coupled line sections using a first transmission line; wherein the second port is connected with the last of the coupled line sections using a second transmission line; wherein the electrical filter comprises an open stub; wherein a length of the open stub is chosen such that an electrical length of the open stub is equal, within a tolerance of +/20 percent, to a fourth of a wavelength of a signal having a frequency of twice a passband center frequency of the filter.

An electrical filter structure for forwarding an electrical signal from a first port to a second port in a frequency selective manner, wherein the filter is an edge-coupled filter, the filter comprising: a plurality of coupled line sections coupled in a series, comprising at least a first coupled line section and a last coupled line section; wherein the first port is connected with the first of the coupled line sections using a first transmission line; wherein the second port is connected with the last of the coupled line sections using a second transmission line; wherein the electrical filter comprises an open stub; wherein a length of the open stub is chosen such that an electrical length of the open stub is equal, within a tolerance of +/20 percent, to a fourth of a wavelength of a signal having a frequency of twice a passband center frequency of the filter.

A network device includes an interface configured to be coupled to a transmission line that simultaneously carries AC power and RF modulated content; content processing circuitry configured to route content communicated via the transmission line to one or more secondary network devices; and a component coupled to the interface to couple and decouple RF modulated content together with AC power communicated over the conductor extending the RF spectrum to 3 GHz. The component includes a core. The core includes a first portion having a conical geometry and a second portion having a cylindrical geometry. A wire makes a plurality of turns around the core starting from the first portion and ending in the second portion.

A network device includes an interface configured to be coupled to a transmission line that simultaneously carries AC power and RF modulated content; content processing circuitry configured to route content communicated via the transmission line to one or more secondary network devices; and a component coupled to the interface to couple and decouple RF modulated content together with AC power communicated over the conductor extending the RF spectrum to 3 GHz. The component includes a core. The core includes a first portion having a conical geometry and a second portion having a cylindrical geometry. A wire makes a plurality of turns around the core starting from the first portion and ending in the second portion.

A signal transmission device includes a communication unit that is connected to an electronic device by a signal wiring and performs communication with the electronic device via the signal wiring, a signal processing unit that performs signal processing related to the communication, a power supply unit that supplies direct current to the electronic device via the signal wiring, and a filter circuit connected between the signal wiring and the power supply unit. The filter circuit includes a plurality of filters having frequency characteristics different from each other, and the signal processing unit acquires communication quality information indicating quality of the communication in at least two or more frequency bands, and determines a state of the filter circuit based on the communication quality information.

A signal transmission device includes a communication unit that is connected to an electronic device by a signal wiring and performs communication with the electronic device via the signal wiring, a signal processing unit that performs signal processing related to the communication, a power supply unit that supplies direct current to the electronic device via the signal wiring, and a filter circuit connected between the signal wiring and the power supply unit. The filter circuit includes a plurality of filters having frequency characteristics different from each other, and the signal processing unit acquires communication quality information indicating quality of the communication in at least two or more frequency bands, and determines a state of the filter circuit based on the communication quality information.

An encoder operable to filter audio signals into a plurality of frequency band components, generate quantized digital components for each band, identify a potential for pre-echo events within the generated quantized digital components, generate an approximate signal by decoding the quantized digital components using inverse pulse code modulation, generate an error signal by comparing the approximate signal with the sampled audio signal, and process the error signal and quantized digital components. The encoder operable to process the error signal by processing delayed audio signals and Q band values, determining the potential for pre-echo events from the Q band values, and determining scale factors and MDCT block sizes for the potential for pre-echo events. The encoder operable to transform the error signal into high resolution frequency components using the MDCT block sizes, quantize the scale factors and frequency components, and encode the quantized lines, block sizes, and quantized scale factors for inclusion in the bitstream.

An encoder operable to filter audio signals into a plurality of frequency band components, generate quantized digital components for each band, identify a potential for pre-echo events within the generated quantized digital components, generate an approximate signal by decoding the quantized digital components using inverse pulse code modulation, generate an error signal by comparing the approximate signal with the sampled audio signal, and process the error signal and quantized digital components. The encoder operable to process the error signal by processing delayed audio signals and Q band values, determining the potential for pre-echo events from the Q band values, and determining scale factors and MDCT block sizes for the potential for pre-echo events. The encoder operable to transform the error signal into high resolution frequency components using the MDCT block sizes, quantize the scale factors and frequency components, and encode the quantized lines, block sizes, and quantized scale factors for inclusion in the bitstream.

Systems and methods for improved acoustic echo cancellation are provided. In various embodiments, a microphone located in the loudspeaker enclosure provides a first signal that is used to estimate the loudspeaker displacement which is proportional to the sound pressure level (SPL) inside the enclosure. A second signal is then derived by mapping the displacement to the loudspeaker's force factor (Bl(x)) and then modulating this by a measured current to a voice coil inside the speaker to provide an estimate of the force acting on the moving mass of the loudspeaker. The first signal is highly correlated with the echo signal for low frequencies and the second signal is highly correlated with the echo signal for high frequencies. The two signals are then combined to provide a single improved AEC reference signal.

Systems and methods for improved acoustic echo cancellation are provided. In various embodiments, a microphone located in the loudspeaker enclosure provides a first signal that is used to estimate the loudspeaker displacement which is proportional to the sound pressure level (SPL) inside the enclosure. A second signal is then derived by mapping the displacement to the loudspeaker's force factor (Bl(x)) and then modulating this by a measured current to a voice coil inside the speaker to provide an estimate of the force acting on the moving mass of the loudspeaker. The first signal is highly correlated with the echo signal for low frequencies and the second signal is highly correlated with the echo signal for high frequencies. The two signals are then combined to provide a single improved AEC reference signal.