| 摘要 |
<p>An oscillator (figure 2) of balanced design in which a resonant impedance network (R) is connected between the control ports (b) of two matched transistors (T1, T2), and a capacitance (C) is connected in parallel, across the two inputs (e) of these transistors. The inputs (e) of the transistors (T1, T2) are connected each to a matched current source (S1, S2). The signals at the transistor outputs (C) are applied across a differential load (ZL). Signals of resonant frequency (fR) in each arm of the oscillator are equal in magnitude but opposite in phase. Signals at resonant frequency (fR) thus add constructively, but since current swings are balanced in each arm, radiation and back conduction is effectively reduced. For high frequency operation, bipolar transistors (T1, T2) are utilised. In other applications, other transistor types may be adopted. The current sources (S1,S2) can be modulated and an IP mixer output derived. In an equivalent arrangement, an inductance (L) and resonant network (R) replace the resonant network (R) and capacitance (C) just mentioned.</p> |
