Receiver

A receiver that receives a transmission signal into which an analog signal and a digital signal are incorporated, the carriers of the analog and digital signal having an identical center frequency, the digital signal having an upper side digital signal which is located in a higher frequency range on a frequency axis than the analog signal and a lower side digital signal which is located in a lower frequency range on the frequency axis than the analog signal, the receiver comprising:

• a narrow band pass filter configured with a pass band centered substantially at the identical center frequency of the carriers of the analog and digital signals, the narrow band pass filter further being configured to receive and filter the transmission signal such that the upper side and lower side digital signals are attenuated and the analog signal is allowed to pass through an output of the narrow band pass filter;
• a wide band pass filter configured to receive and filter the transmission signal such that the analog signal and the upper side and lower side digital signals to pass through an output of the wide band pass filter;
• first and second band pass filters operably connected to the output of the wide band pass filter in order to receive the filtered transmission signal output by the wide band pass filter, the first band pass filter further being configured to pass through the upper side digital signal while attenuating the analog signal and the lower side digital signal, the second band pass filter further being configured to pass through the lower side digital signal while attenuating the analog signal and the upper side digital signal;
• a selecting unit operably connected to the outputs of the narrow and wide band pass filters, the selecting unit being configured to output a selected one of the outputs of the narrow band pass filter means and the wide band pass filter;
• a signal processing device configured to receive the output of the selecting unit, the signal processing device further being configured to demodulate either the analog signal or the digital signal from the selected one of the outputs of the narrow and wide band pass filters;
• and
• a selection controller configured to receive the outputs of the first and second band pass filters and control which of the outputs of the narrow and wide band pass filters is selected to be output by the selecting unit to the signal processing device according to receive levels of the upper side digital signal and the lower side digital signal.

A method comprising:

• receiving a transmission signal into which an analog signal and a digital signal are incorporated, the carriers of the analog and digital signal having an identical center frequency, the digital signal having an upper side digital signal which is located in a higher frequency range on a frequency axis than the analog signal and a lower side digital signal which is located in a lower frequency range on the frequency axis than the analog signal;
• applying narrow band pass filtering to the received transmission signal which attenuates the upper side and lower side digital signals while passing through the analog signal;
• applying wide band pass filtering to the received transmission signal which passes through the analog signal and the upper side and lower side digital signals;
• applying additional filtering to the resultant signal of the wide band pass filtering to attenuate the analog signal while passing through the upper side digital signal and the lower side digital signals;
• selecting the resultant signal of either the narrow band filtering or the wide band filtering according to receive levels of the upper side digital signal and the lower side digital signal passed through by the additional filtering;
• and
• selectively demodulating either the analog signal or the digital signal from the selected resultant signal of filtering.