| 摘要 |
<p>PURPOSE:To enable a clutter due to a sea-level reflection wave to be suppressed over a wide dynamic range. CONSTITUTION:Two variable gain intermediate frequency amplifiers 1 and 2 which are connected in series by placing tuning circuits 3 and 4 are subjected to gain control by a first gain control voltage S4 and a second gain control voltage S5 according to two systems of gain-control circuits, respectively, and then a characteristic at a lapse of time of degree of amplification by two variable gain intermediate frequency amplifiers 1 and 2 becomes a straight line by these two gain-controlling voltages and at the same time a dynamic range is also expanded. A buffer circuit 7 receives a trigger pulse S3, a first gain- controlling voltage S4 is generated by a monostable multivibrator 8a, a CR differential circuit 9a, and an amplifier 10a, and then a second gain-controlling voltage S5 which is delayed from the first gain-controlling voltage S4 is generated by a monostable multivibrator 8b, a CR differential circuit 9b, and an amplifier 10b. A sea-level reflection suppression variable resistor 11 allows an output pulse height of the monostable multivibrators 8a and 8b to be variable and time versus degree-of-amplitude characteristic by two variable gain intermediate frequency amplifiers 1 and 2 to be shifted in parallel.</p> |
