Television receiving device with a sound channel operating in accordance with the intercarrier method
In a television receiving device according to the invention, a frequency converter circuit (21) is connected between the input filter (19) and a switchable demodulator (29) of the sound channel (7), which is connected to the output (2) of the tuner (1) or the IF stage (3, 4) following it. This conve...
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Zusammenfassung: | In a television receiving device according to the invention, a frequency converter circuit (21) is connected between the input filter (19) and a switchable demodulator (29) of the sound channel (7), which is connected to the output (2) of the tuner (1) or the IF stage (3, 4) following it. This converter circuit converts the sound carrier (T1) and the picture carrier (B1) of the intermediate frequency television signal into a second IF frequency (ZF2) in which these two carriers have much lower frequencies (fB2) and (fT2). As a result, the reference circuit (30) of the switchable demodulator (29) can also assume a lower frequency. In the reference circuit (30), this allows tuning means having higher circuit capacities and a higher quality factor to be used. The result is a lower influence of noise effects of the integrated circuit (27) and of the picture carrier and of asymmetries on the sound reproduction. |
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