| 摘要 |
<p>A receiver circuit, particularly an integrated, zero IF receiver circuit in which a direct conversion IF stage (26) is separated from an antenna (10) by a further frequency conversion stage (18) which is coupled by ac coupling means to the direct conversion IF stage (26). A single crystal oscillator (68) generates a frequency which is multiplied prior to being applied as a local oscillator signal to the further frequency conversion stage (18) and is used to produce another frequency, which is divided to block harmonics, prior to being applied as quadrature related local oscillator signals to the direct conversion IF stage (26). The direct conversion IF stage (26) includes several dc nulling stages (56, 58; 60, 62; 64, 66) for compensating for dc offsets.</p> |
