Analog-digital converting apparatus and radio communication terminal

A radio communication terminal comprising:

• a RF unit that down-converts a radio wave into an analog input signal;
• an analog-digital converting unit that converts the analog input signal into a digital output signal;
• a buffer unit that temporary stores the digital output signal for a plurality of samples and outputs the samples in time-series;
• a clipping detecting unit that detects a first sample having a signal value corresponding to a clipping level of the analog-digital converting unit from among the samples of the digital output signal;
• an interpolating unit that rewrites the signal value of the first sample stored in the buffer unit into an estimated signal value that is obtained by estimating a signal value at a time corresponding to a time of the first sample by an interpolation using at least one of (1) a set of second and third samples that are samples previous to the first sample and (2) a set of fourth and fifth samples that are samples subsequent to the first sample;
• a carrier sensing unit that analyzes the signal value rewritten by the interpolating unit;
• and
• a data transmitting unit that stops data transmission in a frequency band when another signal is detected in the frequency band due to the analysis by the carrier sensing unit and performs data transmission in the frequency band when no other signal is detected in the frequency band.

A computer readable storage medium that stores a program product for causing a computer, which controls an analog-digital converting apparatus having:

• an analog-digital converting unit that converts an analog input signal into a digital output signal;
• and a buffer unit temporarily stores the digital output signal for a plurality of samples and outputs the samples in time-series, to perform a process comprising:
• detecting a first sample having a signal value corresponding to a clipping level of the analog-digital converting unit from among the samples of the digital output signal;
• and
• rewriting the signal value of the first sample stored in the buffer unit into an estimated signal value that is obtained by estimating a signal value at a time corresponding to a time of the first sample by an interpolation using at least one of (1) a set of second and third samples that are sample previous to the first sample and (2) a set of fourth and fifth samples that are samples subsequent to the first sample;
• measuring a frequency at which a sample having a signal value corresponding to the clipping level of the analog-digital converting unit is detected;
• and
• changing an amplitude of the analog input signal corresponding to the measured frequency.