| 摘要 |
A microphone arrangement with improved directional characteristics is provided with at least two microphones (100, 102) and a signal processing arrangement (105). The signal processing arrangement is provided with a first (108) and a second input (109) for receiving the microphone signals of the at least two microphones. The inputs (108,109) are coupled to signal inputs of a first (110) and a second (111) multiplication circuit. The multiplication circuits are provided with control inputs for receiving respective first and second control signals, and with signal outputs. A control signal generator (112) is provided for generating the first and second control signals for the multiplication circuits (110,111). An arrangement (114) for a power corrected summation is provided, having a first and a second input coupled to the outputs of the first and second multiplication circuit, respectively, and having an output. A signal combination circuit (116) is provided with a first input (117) coupled to the output of the power corrected summation arrangement (114), a second input (118) coupled to one of the at least two microphones (102), and an output (119) coupled to the output (120) of the combination circuit (116). The first multiplication circuit (110) is adapted to multiply the signal applied to its input by a multiplication factor A*(1−g)1/2, under the influence of the first control signal. The second multiplication circuit (111) is adapted to multiply the signal applied to its input by a multiplication factor B*g1/2 under the influence of the second control signal. The multiplication factor g is frequency dependent (g[f]), and A and B are constant values, whose absolute values are preferably equal to 1. Further, A=B or A=−B applies. Preferably, the multiplication factor g[f], below a first frequency value, has a smaller value for increasing frequencies. Below a second frequency value that is smaller than the first frequency value, g[f] is a constant value (V), preferably equal to zero. (FIG. 2a) Thereby, a microphone arrangement can be obtained which exhibits a desired directional characteristics over an increased frequency range. |
