| 摘要 |
A current steering mechanism is provided in a radio transmitter (e.g., a multiband radio transmitter) to provide compatibility with a variety of baseband parts. Different proportions of an input signal current ("in") may be steered to a dummy load ( 103 ), a mixer for a first band ( 106 ), and a mixer for a second band (108). In one example, five different loads are provided, one dummy load ( 103 ) and two different loads ( 105, 107 ) for each band. Possibilities include: 1. All current steered into dummy load via transistor A; 2. All current steered into Band 1 mixer via transistor B; 3. All current steered into a Band 1 mixer via transistor C, causing 6 dB input signal amplification; 4. All current steered into Band 2 mixer via transistor E; 5. All current steered into a Band 2 mixer via transistor D, causing 6 dB input signal amplification; 6. Like cases 2-5 but with diversion of some portion of current via a dummy load for attenuation of input signal in 1 dB steps.
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