| 摘要 |
1. Battery-powered, portable call receiver responsive to the wireless reception of at least one call signal transmitted as a coded sequence of oscillation packets which are equal in length and of a single frequency, these oscillation packets having intervals between them of two different lengths, these intervals being decisive for the information content of the sequence, containing an amplifier (1) amplifying the signals arriving at its input and supplying them to a band-pass filter (4) tuned to the said frequency, further containing a monostable multivibrator (20, 21, 23, 24, 25, 27) which cannot be influenced while in operative position and is triggered by signals occurring at the output of the band-pass filter (4), the holding time of the multivibrator corresponding to the transmitted length of the said oscillation packets and its operating states reproducing the transmitted signal, further containing, for the series-to-parallel conversion of the transmitted signal reproduced by the first multivibrator, a shift register (7) needing for its operation a feed voltage higher than the battery voltage, and containing a DC voltage transformer (16) for producing the feed voltage needed for operating the shift register, characterized by first circuit means (46) influenced by the multivibrator (20, 21, 23, 24, 25, 27), which circuit means are put into operative state by this multivibrator during its own operative state and which feed the DC voltage transformer (16) in their operative state and interrupt this feed in their rest state. |
