Transmitting apparatus and method of adjusting gain of signal to be transmitted, and receiving apparatus and method of adjusting gain of received signal

A transmitting apparatus having gain varying means for adjusting a gain of a signal to be transmitted using said gain varying means, wherein said gain varying means comprises:

• first signal line selecting means having a plurality of input terminals, a plurality of output terminals, and a control terminal for switching a connection relationship between said plurality of input terminals and said plurality of output terminals;
• second signal line selecting means having a plurality of input terminals, at least one output terminal, and a control terminal for switching a connection relationship between said plurality of input terminals and said at least one output terminal;
• third signal line selecting means having at least one input terminal, a plurality of output terminals, and a control terminal for switching a connection relationship between said at least one input terminal and said plurality of output terminals;
• a plurality of first signal lines for connecting, on a one-by-one basis, said plurality of output terminals of said first signal line selecting means to said plurality of input terminals of said second signal line selecting means, and having different gains from each other by signal amplifying means;
• a plurality of second signal lines for connecting, on a one-by-one basis, said plurality of output terminals of said third signal line selecting means to said plurality of input terminals of said first signal line selecting means, and having different pass band characteristics from each other by filter means;
• and
• signal line control means for controlling the switching of the connection relationship in each of said first signal line selecting means, said second signal line selecting means, and said third signal line selecting means by applying control signals to said control terminal of said first signal line selecting means, said second signal line selecting means, and said third signal line selecting means, respectively,
• wherein said signal line control means selects an optimal signal line from said plurality of first signal lines and said plurality of second signal lines for adjusting the gain on a signal to be transmitted, which is supplied to the at least one input terminal of said third signal line selecting means, and to switch a pass band.

A transmitting apparatus having gain varying means for adjusting a gain of a signal to be transmitted using said gain varying means, wherein said gain varying means comprises:

• first signal line selecting means having at least one input terminal, a plurality of output terminals, and a control terminal for switching a connection relationship between said at least one input terminal and said plurality of output terminals;
• second signal line selecting means having a plurality of input terminals, a plurality of output terminals, and a control terminal for switching a connection relationship between said plurality of input terminals and said plurality of output terminals;
• third signal line selecting means having a plurality of input terminals, at least one output terminal, and a control terminal for switching a connection relationship between said plurality of input terminals and said at least one output terminal;
• a plurality of first signal lines for connecting, on a one-by-one basis, said plurality of output terminals of said first signal line selecting means to said plurality of input terminals of said second signal line selecting means, and having different gains from each other by signal amplifying means;
• a plurality of second signal lines for connecting, on a one-by-one basis, said plurality of output terminals of said second signal line selecting means to said plurality of input terminals of said third signal line selecting means, and having different pass band characteristics from each other by filter means;
• and
• signal line control means for controlling the switching of the connection relationship in each of said first signal line selecting means, said second signal line selecting means, and said third signal line selecting means by applying control signals to said control terminal of said first signal line selecting means, said second signal line selecting means, and said third signal line selecting means, respectively,
• wherein said signal line control means selects an optimal signal line from said plurality of first signal lines and said plurality of second signal lines for adjusting the gain on a signal to be transmitted, which is supplied to at least one input terminal of said first signal line selecting means, and to switch a pass band.

A transmitting apparatus having gain varying means for adjusting a gain of a signal to be transmitted using said gain varying means, wherein said gain varying means comprises:

• first signal line selecting means having a plurality of input terminals, a plurality of output terminals, and a control terminal for switching a connection relationship between said plurality of input terminals and said plurality of output terminals;
• second signal line selecting means having a plurality of input terminals, a plurality of output terminals, and a control terminal for switching a connection relationship between said plurality of input terminals and said plurality of output terminals;
• third signal line selecting means having at least one input terminal, a plurality of output terminals, and a control terminal for switching a connection relationship between said at least one input terminals and said plurality of output terminals;
• fourth signal line selecting means having a plurality of input terminals, at least one output terminal, and a control terminal for switching a connection relationship between said plurality of input terminals and said at least one output terminal;
• a plurality of first signal lines for connecting, on a one-by-one basis, said plurality of output terminals of said first signal line selecting means to said plurality of input terminals of said second signal line selecting means, and having different gains from each other by signal amplifying means;
• a plurality of second signal lines for connecting, on a one-by-one basis, said plurality of output terminals of said third signal line selecting means to said plurality of input terminals of said first signal line selecting means, and having different pass band characteristics from each other by filter means;
• a plurality of third signal lines for connecting, on a one-by-one basis, said plurality of output terminals of said second signal line selecting means to said plurality of input terminals of said fourth signal line selecting means, and having different pass band characteristics from each other by filter means;
• and
• signal line control means for controlling the switching of the connection relationship in each of said first line selecting means, said second line selecting means, said third line selecting means, and said fourth signal line selecting means by applying control signals to said control terminal of each of said first line selecting means, said second line selecting means, said third line selecting means, and said fourth signal line selecting means,
• wherein said signal line control means selects an optimal signal line from said plurality of first, said plurality of second, and said plurality of third signal lines for adjusting the gain on a signal to be transmitted, which is supplied to at least one input terminal of said third signal line selecting means, and to switch a pass band.

The method of adjusting a gain of a signal to be transmitted, comprising the steps of:

• providing a plurality of signal lines having different gains from each other by signal amplifying means;
• examining a first level of a signal to be transmitted, required at an output side of said signal line, and examining a second level of the signal to be transmitted on an input side of said signal line;
• determining which signal line of said plurality of signal lines is selected in accordance with a level difference between said first level and said second level;
• and
• optimally adjusting the gain on said signal to be transmitted by appropriately selecting said signal line in accordance with a result of said determining step.