Abstract: A reception device receives a radio frequency (RF) signal and obtains a data signal from the RF signal in a desired reception channel. The reception device includes a bandpass filter, and first and second test signals are input to the bandpass filter in the test mode to obtain bandpass-filtered first and second test signals, respectively. Each of frequencies of the first and second test signals is lower and higher than a frequency of the desired reception channel, respectively. The reception device detects lower and higher frequency signal intensities from the bandpass-filtered first and second test signals, respectively, in the test mode, and adjusts a central frequency of the passband of the bandpass filter using a difference between the lower and higher frequency signal intensities so as to reduce a difference between the central frequency of the passband and the frequency of the desired reception channel.

Abstract: It is determined, on the basis of a signal component of a low frequency band and a signal component of a desired channel band of an intermediate frequency signal, whether an interfering wave is a far-off interfering wave which exists out of a low frequency band, an out-of-channel-band interfering wave which exists out of a channel band, or an in-channel-band interfering wave which exists in the channel band. When the interfering wave is determined to be the far-off interfering wave, the operation current of a circuit in the receiver is made lower than those in a case where the interfering wave is the out-of-channel-band or in-channel-band interfering wave.

Abstract: A reception device receives a radio frequency (RF) signal and obtains a data signal from the RF signal in a desired reception channel. The reception device includes a bandpass filter, and first and second test signals are input to the bandpass filter in the test mode to obtain bandpass-filtered first and second test signals, respectively. Each of frequencies of the first and second test signals is lower and higher than a frequency of the desired reception channel, respectively. The reception device detects lower and higher frequency signal intensities from the bandpass-filtered first and second test signals, respectively, in the test mode, and adjusts a central frequency of the passband of the bandpass filter using a difference between the lower and higher frequency signal intensities so as to reduce a difference between the central frequency of the passband and the frequency of the desired reception channel.

Abstract: It is determined, on the basis of a signal component of a low frequency band and a signal component of a desired channel band of an intermediate frequency signal, whether an interfering wave is a far-off interfering wave which exists out of a low frequency band, an out-of-channel-band interfering wave which exists out of a channel band, or an in-channel-band interfering wave which exists in the channel band. When the interfering wave is determined to be the far-off interfering wave, the operation current of a circuit in the receiver is made lower than those in a case where the interfering wave is the out-of-channel-band or in-channel-band interfering wave.

Abstract: A signal receiving device receives an incoming signal to obtain a frequency signal. The signal receiving device has a multi-filter device. The frequency signal is subjected to frequency selection processing by using the multi-filter device. The multi-filter device has a plurality of filters whose frequency characteristics are different from each other. The filters are connected in series. If the received signal intensity is higher than prescribed threshold intensity, the center frequency of at least one of the filters in the multi-filter device is biased.

Abstract: A memory card includes: a main body of the memory card in which a notched section is formed; a semiconductor memory; and a write/nonwrite setting element for setting the write/nonwrite state of data in the semiconductor memory, the write/nonwrite setting element being slidably fitted in the notched section, wherein the main body of the memory card includes an upper main body and a lower main body; at least one of the upper main body and the lower main body has an elastic guide formed within the notched section; the write/nonwrite setting element slides along the elastic guide so as to set the write/nonwrite state of the data in the semiconductor memory; and the elastic guide has an engagement portion for engagedly stopping the write/nonwrite setting element so as to select the position of the write/nonwrite setting element with respect to the elastic guide.

Abstract: A memory card includes: a main body of the memory card in which a notched section is formed; a semiconductor memory; and a write/nonwrite setting element for setting the write/nonwrite state of data in the semiconductor memory, the write/nonwrite setting element being slidably fitted in the notched section, wherein the main body of the memory card includes an upper main body and a lower main body; at least one of the upper main body and the lower main body has an elastic guide formed within the notched section; the write/nonwrite setting element slides along the elastic guide so as to set the write/nonwrite state of the data in the semiconductor memory; and the elastic guide has an engagement portion for engagedly stopping the write/nonwrite setting element so as to select the position of the write/nonwrite setting element with respect to the elastic guide.

Abstract: A memory card includes: a main body of the memory card in which a notched section is formed; a semiconductor memory; and a write/nonwrite setting element for setting the write/nonwrite state of data in the semiconductor memory, the write/nonwrite setting element being slidably fitted in the notched section, wherein the main body of the memory card includes an upper main body and a lower main body; at least one of the upper main body and the lower main body has an elastic guide formed within the notched section; the write/nonwrite setting element slides along the elastic guide so as to set the write/nonwrite state of the data in the semiconductor memory; and the elastic guide has an engagement portion for engagedly stopping the write/nonwrite setting element so as to select the position of the write/nonwrite setting element with respect to the elastic guide.

Abstract: A memory card includes: a main body of the memory card in which a notched section is formed; a semiconductor memory; and a write/nonwrite setting element for setting the write/nonwrite state of data in the semiconductor memory, the write/nonwrite setting element being slidably fitted in the notched section, wherein the main body of the memory card includes an upper main body and a lower main body; at least one of the upper main body and the lower main body has an elastic guide formed within the notched section; the write/nonwrite setting element slides along the elastic guide so as to set the write/nonwrite state of the data in the semiconductor memory; and the elastic guide has an engagement portion for engagedly stopping the write/nonwrite setting element so as to select the position of the write/nonwrite setting element with respect to the elastic guide.

Abstract: A memory card includes: a main body of the memory card in which a notched section is formed; a semiconductor memory; and a write/nonwrite setting element for setting the write/nonwrite state of data in the semiconductor memory, the write/nonwrite setting element being slidably fitted in the notched section, wherein the main body of the memory card includes an upper main body and a lower main body; at least one of the upper main body and the lower main body has an elastic guide formed within the notched section; the write/nonwrite setting element slides along the elastic guide so as to set the write/nonwrite state of the data in the semiconductor memory; and the elastic guide has an engagement portion for engagedly stopping the write/nonwrite setting element so as to select the position of the write/nonwrite setting element with respect to the elastic guide.

Abstract: A memory card includes: a main body of the memory card in which a notched section is formed; a semiconductor memory; and a write/nonwrite setting element for setting the write/nonwrite state of data in the semiconductor memory, the write/nonwrite setting element being slidably fitted in the notched section, wherein the main body of the memory card includes an upper main body and a lower main body; at least one of the upper main body and the lower main body has an elastic guide formed within the notched section; the write/nonwrite setting element slides along the elastic guide so as to set the write/nonwrite state of the data in the semiconductor memory; and the elastic guide has an engagement portion for engagedly stopping the write/nonwrite setting element so as to select the position of the write/nonwrite setting element with respect to the elastic guide.

Abstract: A memory card includes: a main body of the memory card in which a notched section is formed; a semiconductor memory; and a write/nonwrite setting element for setting the write/nonwrite state of data in the semiconductor memory, the write/nonwrite setting element being slidably fitted in the notched section, wherein the main body of the memory card includes an upper main body and ail lower main body; at least one of the upper main body and the lower main body has an elastic guide formed within the notched section the write/nonwrite setting element slides along the elastic guide so as to set the write/nonwrite state of the data in the semiconductor memory; and the elastic guide has an engagement portion for engagedly stopping the write/nonwrite setting element so as to select the position of the write/nonwrite setting element with respect to the elastic guide.