| 摘要 |
A method of varying the gain of an amplifier and an amplifier array are provided. The amplifier array includes two or more amplifier stages ( 201, 202 ) connected in parallel with each amplifier stage having a gain control means. Input signal means ( 203, 204 ) are provided for each amplifier stage with the input signals of the amplifier stages being of different amplitude. Means for enabling and disabling an amplifier stage ( 216 ) are provided and means for summing the outputs of the enabled amplifier stages obtain an output signal ( 212 ). The gain of the amplifier array has a range from a low gain setting with a first amplifier stage ( 202 ) enabled, through increasing gain settings as the gain of the first amplifier stage is increased from a minimum to a maximum gain, a second amplifier stage ( 201 ) can then be enabled in addition to the first amplifier stage and the gain of the second amplifier stage increased from a minimum to a maximum gain, further amplifier stages are enabled as available up to a maximum gain setting for the amplifier array. Each amplifier stage that is enabled has a decreasingly attenuated input signal and a final amplifier stage to be enabled has a full input signal ( 203 ).
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