Transmission/reception integrated radio-frequency apparatus
First Claim
1. A transmission/reception integrated radio-frequency apparatus comprising,an input/output terminal for inputting/outputting of a radio-frequency signal;
- a reception system block for processing a reception radio-frequency signal supplied to the input/output terminal;
a transmission processing section including a semiconductor element for outputting a transmission radio-frequency signal to the input/output terminal;
a first high-pass filter connected between the reception system block and the input/output terminal and having a first cut-off frequency (lower-limit frequency) less than a lower-limit frequency of reception frequencies;
a second high-pass filter connected to an output terminal of the transmission processing section and having a second cut-off frequency (lower-limit frequency) in a frequency band lower than said first cut-off frequency;
a low-pass filter connected between the second high-pass filter and the input/output terminal and having a cut-off frequency (upper-limit frequency) in a frequency band which is higher than said second cut-off frequency and tower than said first cut-off frequency; and
an overvoltage breakdown protection circuit connected between the output terminal of the transmission processing section and the second high-pass filter.
1 Assignment
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Accused Products
Abstract
There is provided a highly reliable transmission/reception integrated radio-frequency apparatus which can achieve a high communication quality in a cable modem. A reception RF signal is input to a reception system block via an input/output terminal, converted to an intermediate-frequency signal, and output from a terminal. An output terminal of a transmission processing section of a transmission system block is connected to the input/output terminal via an overvoltage protection circuit, a high-pass filter functioning as a countermeasure to overvoltage, and a low-pass filter for suppressing harmonics produced from the high-pass filter.
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Citations
3 Claims
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1. A transmission/reception integrated radio-frequency apparatus comprising,
an input/output terminal for inputting/outputting of a radio-frequency signal; -
a reception system block for processing a reception radio-frequency signal supplied to the input/output terminal; a transmission processing section including a semiconductor element for outputting a transmission radio-frequency signal to the input/output terminal; a first high-pass filter connected between the reception system block and the input/output terminal and having a first cut-off frequency (lower-limit frequency) less than a lower-limit frequency of reception frequencies; a second high-pass filter connected to an output terminal of the transmission processing section and having a second cut-off frequency (lower-limit frequency) in a frequency band lower than said first cut-off frequency; a low-pass filter connected between the second high-pass filter and the input/output terminal and having a cut-off frequency (upper-limit frequency) in a frequency band which is higher than said second cut-off frequency and tower than said first cut-off frequency; and an overvoltage breakdown protection circuit connected between the output terminal of the transmission processing section and the second high-pass filter. - View Dependent Claims (2, 3)
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Specification