| 摘要 |
404,225. Wireless receiving systems. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, Emmasingel, Eindhoven, Holland. July 17, 1933, No. 20180. Convention date, July 16, 1932. [Class 40 (v).] A wireless aerial is coupled to a distribution system by a number of amplifiers in parallel each effecting optimum amplification for a different range of frequencies and the output transformer of each amplifier is dimensioned to match the line impedance for the frequency range to be amplified. The amplifier 2 for the higher frequencies, as shown, has the output transformer secondary connected in series with a condenser 5 and in parallel with the secondary of the output transformer of the amplifier 1 for the lower frequencies. Alternatively the output transformer secondary windings may be connected in series with a small condenser in parallel with the output transformer of the amplifier operating on the lower frequencies. The inputs to the amplifiers may include band-pass filters so that cross modulation does not produce sum or difference frequencies within the frequency range of the amplifier. |
