Base band circuit of receiver and low cut-off frequency control method
AssigneeNEC Corporation
InventorMasaki Ichihara
Life of this patent
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Abstract
A base band circuit of a receiver and a low cut-off frequency control means can quickly converge transition state due to gain fluctuation with setting a low cut-off frequency of a high-pass filter as low as possible. The base band circuit of a receiver has a variable amplifier variably amplifying a base band signal depending upon a gain control signal, a high-pass filter provided in a path of the base band signal, and a controller detecting variation magnitude of the gain control signal and controlling variation of a low cut-off frequency of the high-pass filter means depending upon the detected variation magnitude.
Claims12
A base band circuit of a receiver comprising:
- variable amplifier means for variably amplifying a base band signal depending upon a gain control signal;
- high-pass filter means provided in a path of said base band signal;
- and
- control means for detecting variation magnitude of said gain control signal and controlling variation of a low cut-off frequency of said high-pass filter means depending upon the detected variation magnitude,
- wherein said control means controls in such a manner that said low cut-off frequency is set at a first value when said variation magnitude is smaller than a predetermined value and said low cut-off frequency is set at a second value higher than said first value when said variation magnitude is greater than or equal to said predetermined value.
A low cut-off frequency control method in a base band circuit of a receiver including variable amplifier means for variably amplifying a base band signal depending upon a gain control signal and high-pass filter means provided in a path of said base band signal, comprising:
- control step of detecting variation magnitude of said gain control signal and controlling variation of a low cut-off frequency of said high-pass filter means depending upon the detected variation magnitude,
- wherein said control means controls in such a manner that said low cut-off frequency is set at a first value when said variation magnitude is smaller than a predetermined value and said low cut-off frequency is set at a second value higher than said first value when said variation magnitude is greater than or equal to said predetermined value.
Dependencies are inferred from the claim text.