JPS648751A - Demodulation system - Google Patents
Demodulation systemInfo
- Publication number
- JPS648751A JPS648751A JP16446487A JP16446487A JPS648751A JP S648751 A JPS648751 A JP S648751A JP 16446487 A JP16446487 A JP 16446487A JP 16446487 A JP16446487 A JP 16446487A JP S648751 A JPS648751 A JP S648751A
- Authority
- JP
- Japan
- Prior art keywords
- mixers
- local oscillation
- demodulation
- reception signal
- branching device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
PURPOSE:To surely enable demodulation regardless of height of the carrier frequency by mixing local oscillation signals having a different phase by 90 deg. to a reception signal, demodulating the result by 2-system of demodulation circuits and adding the result. CONSTITUTION:A radio wave modulated by a responding device 2 is received by a transmission/reception antenna 101 of a questionnaire device 1 and led to mixers 107a, 107b via a circulator 102 and a branching device 106. Moreover, a branching device 103 branches a part of a high frequency power as a local oscillation signal and it is branched into two signals having a different phase of 90 deg. by a branching device 105 and injected to the mixers 107a, 107b. The local oscillation signal and the reception signal are mixed in the mixers 107a, 107b. The output is demodulated respectively by an FSK demodulator or detectors 108a, 108b and added to an adder circuit 109 via LPFs 110a, 110b to obtain information. Thus, the intermission of the reception signal is avoided. Thus, the demodulation is ensured regardless of the height of the carrier frequency.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16446487A JPS648751A (en) | 1987-06-30 | 1987-06-30 | Demodulation system |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16446487A JPS648751A (en) | 1987-06-30 | 1987-06-30 | Demodulation system |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS648751A true JPS648751A (en) | 1989-01-12 |
Family
ID=15793673
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16446487A Pending JPS648751A (en) | 1987-06-30 | 1987-06-30 | Demodulation system |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS648751A (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5819038A (en) * | 1981-07-16 | 1983-02-03 | インタ−ナシヨナル・スタンダ−ド・エレクトリツク・コ−ポレイシヨン | Radio receiver for frequency transient modulation signal |
JPS58106469A (en) * | 1981-12-21 | 1983-06-24 | Nec Corp | Digital sine wave level detecting circuit |
JPS58120334A (en) * | 1982-01-12 | 1983-07-18 | Oki Electric Ind Co Ltd | Narrow-band acoustic signal reception system |
JPS5928750A (en) * | 1982-08-09 | 1984-02-15 | Mitsubishi Electric Corp | Switching device of demodulator |
JPS60100859A (en) * | 1983-11-08 | 1985-06-04 | Nec Corp | Frequency detector |
-
1987
- 1987-06-30 JP JP16446487A patent/JPS648751A/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5819038A (en) * | 1981-07-16 | 1983-02-03 | インタ−ナシヨナル・スタンダ−ド・エレクトリツク・コ−ポレイシヨン | Radio receiver for frequency transient modulation signal |
JPS58106469A (en) * | 1981-12-21 | 1983-06-24 | Nec Corp | Digital sine wave level detecting circuit |
JPS58120334A (en) * | 1982-01-12 | 1983-07-18 | Oki Electric Ind Co Ltd | Narrow-band acoustic signal reception system |
JPS5928750A (en) * | 1982-08-09 | 1984-02-15 | Mitsubishi Electric Corp | Switching device of demodulator |
JPS60100859A (en) * | 1983-11-08 | 1985-06-04 | Nec Corp | Frequency detector |
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