| 摘要 |
PROBLEM TO BE SOLVED: To improve transmission definition in bidirectional CATV transmission and reception by reducing noises and non-consistency at the transient response time of switch operation. SOLUTION: An imbalance/balance converter 2 distributes an input high frequency signal into two signals phase-shifted at 180 deg. and applies them to respective high frequency amplifiers 5 and 6. Afterwards, these output signals are respectively amplified by the respective high frequency amplifiers 5 and 6 and applied later to input terminals 7a and 8a of 1st and 2nd switch means 7 and 8. Concerning the 1st and 2nd switch means 7 and 8, a control signal to become the same phase controls the switch operation so as to connect/ disconnect output terminals 7b and 8b with respective input terminals 11 and 12 of the balance/imbalance converter 13. When two input signals are phase- shifted at 180 deg., the balance/imbalance converter 13 outputs two input signals after synthesizing them to the same phase. Thus, since the noises to be generated at the time of transient response by the 1st and 2nd switch means 7 and 8 can be mutually canceled, interference caused by these noises is reduced and the transmission fidelity of transmission equipment is improved. |
