WO2003026158A1 - Single frequency duplex fm transceiver with digital ssb demulator - Google Patents
Single frequency duplex fm transceiver with digital ssb demulator Download PDFInfo
- Publication number
- WO2003026158A1 WO2003026158A1 PCT/EP2002/009283 EP0209283W WO03026158A1 WO 2003026158 A1 WO2003026158 A1 WO 2003026158A1 EP 0209283 W EP0209283 W EP 0209283W WO 03026158 A1 WO03026158 A1 WO 03026158A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- signals
- output
- transceiver
- phase
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/0003—Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/30—Circuits for homodyne or synchrodyne receivers
- H04B1/302—Circuits for homodyne or synchrodyne receivers for single sideband receivers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/54—Circuits using the same frequency for two directions of communication
- H04B1/56—Circuits using the same frequency for two directions of communication with provision for simultaneous communication in two directions
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/68—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for wholly or partially suppressing the carrier or one side band
Definitions
- This invention relates to transceivers which simultaneously receive and transmit the same signal and/or which receive and transmit signals on the same channel. It has particular application to N-Plex transceivers which permits the reception of many concurrent FM signals whilst simultaneously transmitting on the same frequency.
- a simple application of such a transceiver is also as a booster for transceivers which are out of range of each other. In such an example two persons each trying to transmit and receive signals to each other may have insufficient signal strength to overcome distance and natural obstacles such as e.g. a hill. Such a transceiver located on a hilltop would provide received signals to be rebroadcast.
- Such transceivers also have application where there is a desire to have simultaneous two way (transmitting and receiving) communication from a transceiver to one or more similar transceivers without having to switch to and f om transmit/receive modes. In other words it enables users to communicate as and hear and speak as if they were talking in a room.
- the use of such transceivers in N-Plex communication is known.
- the outputs of the mixers are fed into capacitors 35; this provides AC coupling in the I and Q paths.
- the outputs from the capacitors are each then fed into a low pass filters 12, which defines the channel, and then an amplifier 13.
- the in-phase signal is then shifted through 90 degrees by phase shifter 14 before being summed at 15 to provide the audio output.
- phase shifter 14 When transmitting there will be a leakage signal between the transmit and receive antennas, as shown by the dotted line on the figure, which will be typically larger than any wanted received signal.
- the output of the mixers will be zero, i.e. at a DC level.
- An FM signal received using an SSB (Single Sideband Suppressed Barrier) demodulator provided the FM deviation is small (peak phase deviation is less than 90 degrees).
- the FM signal consists substantially of a carrier component and the first order pair of side-bands.
- an SSB detector may be used to demodulate the signal.
- the phasing method of SSB detection is used in which the I and Q baseband signals are first shifted 90 degrees relative to each other, as mentioned. In this way, if multiple (N) received signals are present on the same frequency a linear superposition occurs and the composite signal may be demodulated as above. In this case the recovered audio will preserve the relative loudness of the individual signals according to their relative RF levels at the antenna and hence their respective ranges.
- FIG. 2 shows the basic configuration of the invention.
- the receiver antenna is input to an amplifier and split into I and Q components as described above and it shows all the same components with identical reference numbers.
- the I and Q components are put through analogue to digital (A/D) converters.
- the I and Q components are then passed through further high and low pass digital filters 17, 18.
- the I component is then phase shifted by 90 degrees at 19. It is then summed digitally with the Q component and the output converted to an analogue signal by D/A converter 20. The shifting is done digitally which allows for many advantages.
- the figure 3 embodiment shows a further preferred refinement. Again it includes all the integers of the previous examples as before.
- the microphone output is duplicated by also being input to an inverter 21 and converted to a digital signal by A/D converter 22; this digital signal is then used to frequency modulate a further oscillator 23, which is a numerically controlled oscillator (NCO) which provides a frequency controlled digital output.
- NCO numerically controlled oscillator
- the output from the oscillator is fed through a time delay ⁇ to give sine ⁇ and cos ⁇ ( ⁇ is an the arbitrary phase angle and this illustrates that these two outputs are orthogonal) before being input via a complex multiplier 24 along with the output from A/D Converters 16. This delay element compensates for the delay through the analogue signal path.
- FIG. 4 shows a yet further refinement.
- This embodiment is similar to that described in example 3; however the audio input is fed directly into A/D converter 22 and modulated by oscillator (NCO).
- NCO modulated by oscillator
- the inverter is not present as a module, as long as the inverter function is performed at some stage e.g. digitally with other functions.
- the sine and cosine output 30, 31 output are input to the time delay. They are also converted into analogue signals using two digital to analogue converters 25, which after passing through low pass filters 26 the I and Q components (transmit signals) are then mixed by mixer 27 with the output of a fixed local oscillator at the frequency of the carrier (fc) via phase shifter 26 and summed at 28 producing the desired FM signal at the output frequency.
- the local oscillator before mixing with the I and Q signals 32, 33 has applied a 90 degree phase shift by shifter 2d.
- the audio in from the microphone is fed through two oscillators compared to the figure 3 embodiment, in such a way as to be input into VCO (Local Oscillator) only after having digital FM modulation previously.
- VCO Local Oscillator
- the inventor has also developed a novel antenna arrangement which obviates the need for two antennas for transmitting and receiving arrangement N-plex system will normally be used in hand held systems where separate receive and transmit antennas are not practicable.
- a simple means of realising a single antenna mixer for use in N-plex systems is shown in figure 5.
- the antenna 30 is connected to one side of a 45 degree delay line 31 and the transmitter to the other via resistor 32.
- the signals at both sides of the delay line are rectified by diodes 33 connecting to two further potentiometers 34 as shown.
- the transmitter output is also rectified and a portion of the rectified signal is effectively subtracted from the other two outputs. Any AM noise on the transmitter signal is nulled by adjustment of the two potentiometers.
- the outgoing signal is delayed by 45 degrees but in the opposite direction as it is travelling in the opposite direction through the delay line. This give a relative phase shift of 90°.
- the product of the received and transmitted signals compared between the two rectifier/detector outputs is therefore at the desired phase quadrature.
- the circuit of figure 5 thus conveniently and neatly performs all the functions within the dotted line of figures 2.
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transceivers (AREA)
Abstract
Description
Claims
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0122196A GB0122196D0 (en) | 2001-09-14 | 2001-09-14 | Improvements to the n-plex transceiver |
GB0122196.9 | 2001-09-14 | ||
GB0208225.3 | 2002-04-10 | ||
GB0208225A GB2380641B (en) | 2001-09-14 | 2002-04-10 | Transceiver |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2003026158A1 true WO2003026158A1 (en) | 2003-03-27 |
Family
ID=26246541
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2002/009283 WO2003026158A1 (en) | 2001-09-14 | 2002-08-19 | Single frequency duplex fm transceiver with digital ssb demulator |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO2003026158A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015041993A1 (en) * | 2013-09-17 | 2015-03-26 | Skyworks Solutions, Inc. | Systems and methods related to carrier aggregation front-end module applications |
US20160171976A1 (en) * | 2014-12-11 | 2016-06-16 | Mediatek Inc. | Voice wakeup detecting device with digital microphone and associated method |
CN105704298A (en) * | 2014-12-11 | 2016-06-22 | 联发科技股份有限公司 | Voice wakeup detecting device and method |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1577514A (en) * | 1976-03-16 | 1980-10-22 | Plessey Co Ltd | Transmitter/receivers |
US4349919A (en) * | 1979-07-06 | 1982-09-14 | Plessey Handel Und Investments Ag | Transmitter/receivers capable of contemporaneous transmission/reception |
US4602227A (en) * | 1984-07-30 | 1986-07-22 | Rca Corporation | Coaxial LC phase-shifter for phase-controlled television broadcast switching circuit |
US4994769A (en) * | 1989-06-05 | 1991-02-19 | Kabuskiki Kaisha Kenwood | SSB modulation and demodulation apparatus |
DE19616368C1 (en) * | 1996-04-24 | 1997-12-11 | Hagenuk Marinekommunikation Gm | Demodulation method for single side band signal |
-
2002
- 2002-08-19 WO PCT/EP2002/009283 patent/WO2003026158A1/en not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1577514A (en) * | 1976-03-16 | 1980-10-22 | Plessey Co Ltd | Transmitter/receivers |
US4349919A (en) * | 1979-07-06 | 1982-09-14 | Plessey Handel Und Investments Ag | Transmitter/receivers capable of contemporaneous transmission/reception |
US4602227A (en) * | 1984-07-30 | 1986-07-22 | Rca Corporation | Coaxial LC phase-shifter for phase-controlled television broadcast switching circuit |
US4994769A (en) * | 1989-06-05 | 1991-02-19 | Kabuskiki Kaisha Kenwood | SSB modulation and demodulation apparatus |
DE19616368C1 (en) * | 1996-04-24 | 1997-12-11 | Hagenuk Marinekommunikation Gm | Demodulation method for single side band signal |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015041993A1 (en) * | 2013-09-17 | 2015-03-26 | Skyworks Solutions, Inc. | Systems and methods related to carrier aggregation front-end module applications |
US9621327B2 (en) | 2013-09-17 | 2017-04-11 | Skyworks Solutions, Inc. | Systems and methods related to carrier aggregation front-end module applications |
US10069615B2 (en) | 2013-09-17 | 2018-09-04 | Skyworks Solutions, Inc. | Front-end modules with switched filter assemblies for carrier aggregation |
US10135469B2 (en) | 2013-09-17 | 2018-11-20 | Skyworks Solutions, Inc. | Uplink and downlink carrier aggregation |
US20160171976A1 (en) * | 2014-12-11 | 2016-06-16 | Mediatek Inc. | Voice wakeup detecting device with digital microphone and associated method |
CN105704300A (en) * | 2014-12-11 | 2016-06-22 | 联发科技股份有限公司 | Voice wakeup detecting device with digital microphone and associated method |
CN105704298A (en) * | 2014-12-11 | 2016-06-22 | 联发科技股份有限公司 | Voice wakeup detecting device and method |
US9775113B2 (en) * | 2014-12-11 | 2017-09-26 | Mediatek Inc. | Voice wakeup detecting device with digital microphone and associated method |
US9779725B2 (en) | 2014-12-11 | 2017-10-03 | Mediatek Inc. | Voice wakeup detecting device and method |
CN105704300B (en) * | 2014-12-11 | 2019-08-09 | 联发科技股份有限公司 | The sound for having digital microphone wakes up arrangement for detecting and correlation technique |
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