| 摘要 |
Mixer arrangement suitable for use in a television receiver operating in the UHF band is disclosed. The arrangement contains a variable gain amplifier stage including a first field effect transistor whose first principal terminal referred to as drain is biased via a load by a DC supply source and whose control terminal referred to as gate receives a first RF signal at a first frequency which is modulated by a second signal at a second frequency applied to the amplifier stage through a variable resistor T2 such that the output signal of the amplifier stage which is available at the first principal drain terminal of the first transistor is formed from the mixture of the first and the second signal. The second signal OL is applied via the variable resistor to the first principal drain terminal of the first transistor T1 resulting in the variation of the amplifier gain occurring from the modulation of the load constituted by the biasing load above and the variable resistor. The second principal terminal referred to as source of the first transistor is directly brought to a reference potential.
|
