| 摘要 |
<p>Extended definition television (EDTV) signals including a compatible composite wideband signal (SWB) and a separate helper or extended definition signal (SNB) are combined (18), for example, for recording purposes (20), using frequency multiplexing techniques. The helper signal (SNB) is applied to a modulator (16), which produces a suppressed carrier modulated signal, to frequency shift the helper signal to a spectral band above the frequency band occupied by the compatible composite wideband signal. The frequency shifted and wideband signal are then added (18) to form the combined signal.</p> |
