| 摘要 |
<p>PURPOSE:To ensure stable operation and broad dynamic range, by obtaining a plurality of signals with different amplitude from an original signal, performing frequency conversion through the addition of the signal and a local oscillating output and further performing logarithmic compression after attenuation or amplification. CONSTITUTION:An original signal given to an input terminal t11 is respectively given to mixers 14, 15 via an attenuator or an amplifier 13. Then, the signal is mixed with an oscillation output of a local oscillator 16 at the mixers 14, 15 and converted into intermediate frequency signals with (G-A) and (G+A) dB. Signals (a)-(e) of the outputs or amplified at intermediate amplifiers 17, 18, 19 are applied to an amplitude limit adder 11. Thus, since signals increased by A dB to the original signal are inputted to each input terminal of the adder 11, the output having the input and output characteristics approximated with the logarithmic characteristics, i.e. the logarithmically compressed outputs can be obtained from an output terminal t12.</p> |
