| 摘要 |
Frequency changing circuits are disclosed which each include an unbalanced input circuit, complementary mixing devices and a balanced output circuit. The mixer input signals are cancelled in the balanced output circuit. Moreover, whatever mixer out-of-phase output signals that are undesirably fed back to the input circuit are cancelled in the unbalanced input circuit. Also, circuitry is disclosed for rendering one or the other of the complementary mixing transistors inoperative so that the other of the complementary transistors can operate as a neutralized amplifier for utilization in a television receiver adapted to receive both VHF and UHF signals.
|
