| 摘要 |
PURPOSE:To attain charging of broadcast for viewing time and the instant collection of charge by extracting a secret call release code from a broadcast signal, comparing the code with a collating code and releasing the secret call when both codes are coincident. CONSTITUTION:A digital code generator 14 is a generator generating a code which acts as a key to the release of secret call of a ciphered desired signal, and when a signal from a signal controller 24 is incoming, the secret call release code is transmitted automatically and led to a comparator 37. On the other hand, since the same secret call release code is included also in a radio wave, the code is extracted in an extracting circuit 25 and compared at the comparator 37, and when both codes are coincident, the secret call release circuit 22 is conductive and a receiving signal output is outputted to a receiving signal output device 23. |
