| 摘要 |
PROBLEM TO BE SOLVED: To receive standard television signals and high definition television signals. SOLUTION: For NTSC signals, a single superheterodyne system for converting them into IF signals in a third mixer and separating a tuned channel from the IF signals in an IF filter for the NTSC signals is used. Also, for the high-definition television signals, a double superheterodyne system for turning them to first IF signals >=10 GHz in a first mixer 10, turning the first IF signals to second IF signals equal to the IF signals of the NTSC signals in a frequency band and separating a tuned channel from the second IF signals in the IF filter 15 for the high definition television signals which is a SAW filter is used. For the IF filter 11 for supplying the first IF signals from the first mixer 10, the band-pass filter of intra-band flatness and low group delay deviation is used. |
