Patent classifications
H04B1/588
Communication apparatus
According to an embodiment, a communication apparatus creates a prediction model taking into consideration of the actual fluctuation of a self-interference signal. The communication apparatus selects, where the self-interference signal has largely fluctuated, a prediction model in accordance with a fluctuation pattern at an early stage of the fluctuation. The communication apparatus generates a cancel signal by control applying a gain and an amount of phase shift represented by the prediction model.
COMMUNICATION APPARATUS
According to an embodiment, a communication apparatus creates a prediction model taking into consideration of the actual fluctuation of a self-interference signal. The communication apparatus selects, where the self-interference signal has largely fluctuated, a prediction model in accordance with a fluctuation pattern at an early stage of the fluctuation. The communication apparatus generates a cancel signal by control applying a gain and an amount of phase shift represented by the prediction model.
Noise reducing receiver
Disclosed is receiver for a noise limited system. A front-end circuit amplifies and band-limits an incoming signal. The amplification increases the signal swing but introduces both thermal and flicker noise. A low-pass band limitation reduces the thermal noise component present at frequencies above what is necessary for correctly receiving the transmitted symbols. This band limited signal is provided to the integrator circuit. The output of the integrator is equalized to reduce the effects of inter-symbol interference and then sampled. The samples are used to apply low frequency equalization (i.e., in response to long and/or unbalanced strings of symbols) to mitigate the effects of DC wander caused by mismatches between the number of symbols of each kind being received.
NOISE REDUCING RECEIVER
Disclosed is receiver for a noise limited system. A front-end circuit amplifies and band-limits an incoming signal. The amplification increases the signal swing but introduces both thermal and flicker noise. A low-pass band limitation reduces the thermal noise component present at frequencies above what is necessary for correctly receiving the transmitted symbols. This band limited signal is provided to the integrator circuit. The output of the integrator is equalized to reduce the effects of inter-symbol interference and then sampled. The samples are used to apply low frequency equalization (i.e., in response to long and/or unbalanced strings of symbols) to mitigate the effects of DC wander caused by mismatches between the number of symbols of each kind being received.
MULTI-FREQUENCY SAMPLING SYSTEM
Techniques are provided for a multi-frequency sampling system. A system implementing the techniques according to an embodiment includes a first bandpass filter to filter a radio frequency (RF) signal to generate a first filtered signal in a first frequency band, and a second bandpass filter to filter the RF signal to generate a second filtered signal in a second frequency band. The system also includes a first analog to digital converter (ADC) operating at a first sampling frequency to convert the first filtered signal to a first digital signal and a second ADC operating at a second sampling frequency to convert the second filtered signal to a second digital signal. The first frequency band is selected to avoid a first Nyquist boundary zone associated with the first sampling frequency and the second frequency band is selected to avoid a second Nyquist boundary zone associated with the second sampling frequency.
OBTAINING ACCURATE TIMING OF ANALOG TO DIGITAL CONVERTER SAMPLES IN CELLULAR MODEM
According to embodiments, an example method for determining an analog-to-digital converter (ADC) output timing in a user equipment may include operating a switch in a first mode to route a system clock from an oscillator to an input of the ADC and determining a first ADC output timing based on a first set of ADC samples generated by the ADC. The method may also include operating the switch in a second mode to route analog signals from a transceiver of the user equipment to the input of the ADC and obtaining a second set of ADC samples generated by the ADC based on the analog signals.
Noise reducing receiver
Disclosed is receiver for a noise limited system. A front-end circuit amplifies and band-limits an incoming signal. The amplification increases the signal swing but introduces both thermal and flicker noise. A low-pass band limitation reduces the thermal noise component present at frequencies above what is necessary for correctly receiving the transmitted symbols. This band limited signal is provided to the integrator circuit. The output of the integrator is equalized to reduce the effects of inter-symbol interference and then sampled. The samples are used to apply low frequency equalization (i.e., in response to long and/or unbalanced strings of symbols) to mitigate the effects of DC wander caused by mismatches between the number of symbols of each kind being received.
NOISE REDUCING RECEIVER
Disclosed is receiver for a noise limited system. A front-end circuit amplifies and band-limits an incoming signal. The amplification increases the signal swing but introduces both thermal and flicker noise. A low-pass band limitation reduces the thermal noise component present at frequencies above what is necessary for correctly receiving the transmitted symbols. This band limited signal is provided to the integrator circuit. The output of the integrator is equalized to reduce the effects of inter-symbol interference and then sampled. The samples are used to apply low frequency equalization (i.e., in response to long and/or unbalanced strings of symbols) to mitigate the effects of DC wander caused by mismatches between the number of symbols of each kind being received.
Measurement of periodically modulated signals under non-coherent operating conditions
A receiver-implemented method is for measuring a periodically modulated signal. The method includes applying a received periodically modulated signal to a mixer of a receiver, the periodically modulated signal not synchronized with the receiver, and tuning a local oscillator (LO) of the mixer using an estimate of actual carrier frequency and an estimate of an arbitrary waveform generator (AWG) sampling rate to obtain a digitized intermediate frequency (IF) signal. The method further includes applying a short time Fourier transform (STFT) to the digitized IF signal, extracting a carrier frequency offset and a AWG sampling rate offset based on the applied STFT, compensating for the carrier frequency offset, and applying a digital correction to the STFT to compensate for the AWG sampling rate offset. Compensating for the carrier frequency offset may include retuning the LO to obtain a new digitized IF signal to which the digital correction is applied.
Noise reducing receiver
Disclosed is receiver for a noise limited system. A front-end circuit amplifies and band-limits an incoming signal. The amplification increases the signal swing but introduces both thermal and flicker noise. A low-pass band limitation reduces the thermal noise component present at frequencies above what is necessary for correctly receiving the transmitted symbols. This band limited signal is provided to the integrator circuit. The output of the integrator is equalized to reduce the effects of inter-symbol interference and then sampled. The samples are used to apply low frequency equalization (i.e., in response to long and/or unbalanced strings of symbols) to mitigate the effects of DC wander caused by mismatches between the number of symbols of each kind being received.