CA2054859C - Down converter for satellite communication system - Google Patents
Down converter for satellite communication systemInfo
- Publication number
- CA2054859C CA2054859C CA 2054859 CA2054859A CA2054859C CA 2054859 C CA2054859 C CA 2054859C CA 2054859 CA2054859 CA 2054859 CA 2054859 A CA2054859 A CA 2054859A CA 2054859 C CA2054859 C CA 2054859C
- Authority
- CA
- Canada
- Prior art keywords
- signal
- intermediate frequency
- terminal
- down converter
- next stage
- 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.)
- Expired - Fee Related
Links
Abstract
A down converter device is used in a satellite communication system to convert a microwave signal to an intermediate frequency signal by the use of a standard signal having a frequency range of several to several tens of MHz, and to apply the intermediate frequency signal to a next stage component. The down converter includes a mixer for producing the intermediate frequency signal which is indicative of the frequency difference between the standard signal and the microwave signal. A separator includes a first terminal for receiving the intermediate frequency signal, a second terminal for producing and supplying the intermediate frequency signal to the next stage component and for receiving the standard signal from the next stage component, a first filter for separating the standard signal, and a third terminal for producing the standard signal to the mixing means. The system has the advantage over prior down converters that only a single connection is required between the converter and the next stage component.
Description
- 1 _ 2054859 DOWN CONVERTER FOR SATELLITE COMMUNICATION SYSTEM
The present invention relates to a down converter for use in satellite communication system, and, more particularly, to a down converter for microwave digital satellite communication.
The local signal used for frequency conversion by the down converter in a microwave digital satellite communication system requires a high quality in terms of frequency probability, frequency stability, and phase noise characteristic.
To enable the prior art to be described with the aid of a diagram, the figures of the drawings will first be listed.
Fig. 1 is a block diagram of a down converter for use in a satellite communication system according to an embodiment of the present invention; and Fig. 2 is a block diagram of a conventional down converter for use in a satellite communication system.
The prior art down converter DC' described below with reference to the Fig. 2 has a microwave signal MS of a frequency such as 12 GHz input to a microwave low noise amplifier 5 through a microwave input terminal 1. The amplifier 5 amplifies the signal MS and produces an amplified microwave signal MSa that is input to a mixing circuit 6.
Through an input terminal 3, a standard signal SS' having a frequency in the order of MHz is inputted to a phase locked oscillator (PLO) 9 which produces a phase synchronized signal SSs' having a frequency such as 2.15 GHz. The phase synchronized signal SSs' is input to a frequency multiplier 8 which produces a local signal sse ~ of a microwave band at a frequency range of ten GHz, by multiplying the signal SSs' by, e.g. five (2.15 GHz X 5 = 10.75 GHz). The local signal sse is input to the mixing circuit 6.
In the mixing circuit 6, the frequency difference between the amplified microwave signal MSa and the local signal sse is obtained to produce an intermediate frequency signal IF' _ - 2 having a frequency range of, for example, 950 MHz. The intermediate frequency signal IF' is input to an intermediate frequency amplifier 7 and is thereby amplified to produce an amplified intermediate frequency signal IFa' at an output terminal 2. DC power is supplied at a terminal 4 to a power source circuit 10 for driving the down converter DC' According to this prior art down converter DC', the terminals 2, 3 and 4 are provided for connection to a next stage circuit component, such as a receiver. Thus, if a cable is used, a 3-line cable is necessary to connect the terminals 2, 3, and 4 to the next stage component.
As a result, this conventional down converter DC' requires a number of lines in a cable, or a number of separate cables, for connection to the next stage component, resulting in difficulties of installation and maintenance, degradation of reliability, and an increase of cost.
The present invention has been developed with a view to substantially solving these disadvantages and has for its essential object to provide an improved down converter for use in a satellite communication system.
To this end, the invention consists of a down converter for converting a microwave signal to an intermediate frequency signal using a standard signal having a frequency range of several to several tens of MHz, and for applying said intermediate frequency signal to a next stage component, said down converter comprising: a mixing means for producing said intermediate frequency signal indicative of a frequency difference between said standard signal and said microwave signal; and a separator means comprising: a first terminal for receiving said intermediate frequency signal; a second terminal for producing and supplying said intermediate frequency signal to said next stage component and for receiving said stAn~rd signal from said next stage component;
a first filter means for separating said standard signal; and a third terminal for producing said standard signal to said mixing means.
205485~
The present invention relates to a down converter for use in satellite communication system, and, more particularly, to a down converter for microwave digital satellite communication.
The local signal used for frequency conversion by the down converter in a microwave digital satellite communication system requires a high quality in terms of frequency probability, frequency stability, and phase noise characteristic.
To enable the prior art to be described with the aid of a diagram, the figures of the drawings will first be listed.
Fig. 1 is a block diagram of a down converter for use in a satellite communication system according to an embodiment of the present invention; and Fig. 2 is a block diagram of a conventional down converter for use in a satellite communication system.
The prior art down converter DC' described below with reference to the Fig. 2 has a microwave signal MS of a frequency such as 12 GHz input to a microwave low noise amplifier 5 through a microwave input terminal 1. The amplifier 5 amplifies the signal MS and produces an amplified microwave signal MSa that is input to a mixing circuit 6.
Through an input terminal 3, a standard signal SS' having a frequency in the order of MHz is inputted to a phase locked oscillator (PLO) 9 which produces a phase synchronized signal SSs' having a frequency such as 2.15 GHz. The phase synchronized signal SSs' is input to a frequency multiplier 8 which produces a local signal sse ~ of a microwave band at a frequency range of ten GHz, by multiplying the signal SSs' by, e.g. five (2.15 GHz X 5 = 10.75 GHz). The local signal sse is input to the mixing circuit 6.
In the mixing circuit 6, the frequency difference between the amplified microwave signal MSa and the local signal sse is obtained to produce an intermediate frequency signal IF' _ - 2 having a frequency range of, for example, 950 MHz. The intermediate frequency signal IF' is input to an intermediate frequency amplifier 7 and is thereby amplified to produce an amplified intermediate frequency signal IFa' at an output terminal 2. DC power is supplied at a terminal 4 to a power source circuit 10 for driving the down converter DC' According to this prior art down converter DC', the terminals 2, 3 and 4 are provided for connection to a next stage circuit component, such as a receiver. Thus, if a cable is used, a 3-line cable is necessary to connect the terminals 2, 3, and 4 to the next stage component.
As a result, this conventional down converter DC' requires a number of lines in a cable, or a number of separate cables, for connection to the next stage component, resulting in difficulties of installation and maintenance, degradation of reliability, and an increase of cost.
The present invention has been developed with a view to substantially solving these disadvantages and has for its essential object to provide an improved down converter for use in a satellite communication system.
To this end, the invention consists of a down converter for converting a microwave signal to an intermediate frequency signal using a standard signal having a frequency range of several to several tens of MHz, and for applying said intermediate frequency signal to a next stage component, said down converter comprising: a mixing means for producing said intermediate frequency signal indicative of a frequency difference between said standard signal and said microwave signal; and a separator means comprising: a first terminal for receiving said intermediate frequency signal; a second terminal for producing and supplying said intermediate frequency signal to said next stage component and for receiving said stAn~rd signal from said next stage component;
a first filter means for separating said standard signal; and a third terminal for producing said standard signal to said mixing means.
205485~
Referring to Fig. 1, the microwave input terminal 1 is connected to the low noise amplifier 5 which is further connected to the mixing circuit 6 which is in turn connected to the intermediate frequency amplifier 7. The intermediate frequency amplifier 7 is then connected to a signal separator 11 which has four terminals T1, T2, T3 and T4. Terminal T1 is connected to the intermediate frequency amplifier 7. Terminal T2 is connected to the phase synchronizing oscillator 9 and in turn to the frequency multiplier 8, which is further connected to the mixing circuit 6. Terminal T3 is connected to the power source circuit 10. Terminal T4 is connected to a junction J that is connected to a high pass filter 12 and a low pass filter 13. The low pass filter 13 is further connected to a DC generator 14 and a standard signal generator lS which generates a standard signal SS having a frequency of several to several tens of MHz.
According to the present embodiment, the down converter DC is defined by circuits 5, 6, 7, 8, 9, 10 and 11. The circuits 12, 13, 14 and 15 are provided in a next stage component, such as a receiver. The connection between the down converter DC and the receiver, i.e., between the terminal T4 and the junction J is by a single line cable L.
The signal separator 11 includes a high pass filter lla, a first low pass filter llb, a band pass filter llc, and a second low pass filter lld.
In operation, a standard signal SS having a frequency of several to several tens of MHz, for example 10 MHz, is generated from the generator 15. This standard signal SS and a DC current from the generator 14 are supplied to the low pass filter 13. The DC current and the standard signal are thus transmitted from the junction J to the terminal T4 through the line L. Because of the high pass filter 12, the standard signal SS and the DC current will not be transmitted to the next stage circuit connected to high pass filter 12.
In the signal separator 11, the standard signal SS and the DC current are transmitted through the first low pass filter llb and are separated by the band pass filter llc and the second low pass filter lld. The band pass filter llc thus produces the standard signal SS of 10 MHz to the oscillator 9 through the terminal T2, and the second low pass filter lld provides the DC current to the power source circuit 10 through the terminal T3.
In the oscillator 9, a phase synchronized signal SSs (2.15 GHz) is produced with reference to the standard signal SS (10 MHz) and is applied to the frequency multiplier 8. In the frequency multiplier 8, the phase synchronized signal SSs is multiplied, e.g., by five, so that a local signal SS~
(10.75 GHz) is applied to the mixing circuit 6.
In the meantime, a microwave signal MS having a high frequency range, such as in the order of 12 GHz, is input to the amplifier 5 through the terminal 1 and further applied to the mixing circuit 6.
In the mixing circuit 6, the frequency difference between the signal MSa (about 12 GHz) and the signal SS~ (10.75 GHz) is obtained to produce an intermediate frequency signal IF
having a frequency in the range of 950 to 1450 MHz. This intermediate frequency signal IF is input to the amplifier 7 and further to the frequency distributor 11 through the terminal T1.
The amplified intermediate frequency signal IFa passes through the high pass filter lla, and is further applied through the line L to the high pass filter 12.
It is noted that the signal IFa will not pass through the low pass filters llb and 13.
The down converter DC thus requires only one cable line L
for its connection to the next stage component.
Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
According to the present embodiment, the down converter DC is defined by circuits 5, 6, 7, 8, 9, 10 and 11. The circuits 12, 13, 14 and 15 are provided in a next stage component, such as a receiver. The connection between the down converter DC and the receiver, i.e., between the terminal T4 and the junction J is by a single line cable L.
The signal separator 11 includes a high pass filter lla, a first low pass filter llb, a band pass filter llc, and a second low pass filter lld.
In operation, a standard signal SS having a frequency of several to several tens of MHz, for example 10 MHz, is generated from the generator 15. This standard signal SS and a DC current from the generator 14 are supplied to the low pass filter 13. The DC current and the standard signal are thus transmitted from the junction J to the terminal T4 through the line L. Because of the high pass filter 12, the standard signal SS and the DC current will not be transmitted to the next stage circuit connected to high pass filter 12.
In the signal separator 11, the standard signal SS and the DC current are transmitted through the first low pass filter llb and are separated by the band pass filter llc and the second low pass filter lld. The band pass filter llc thus produces the standard signal SS of 10 MHz to the oscillator 9 through the terminal T2, and the second low pass filter lld provides the DC current to the power source circuit 10 through the terminal T3.
In the oscillator 9, a phase synchronized signal SSs (2.15 GHz) is produced with reference to the standard signal SS (10 MHz) and is applied to the frequency multiplier 8. In the frequency multiplier 8, the phase synchronized signal SSs is multiplied, e.g., by five, so that a local signal SS~
(10.75 GHz) is applied to the mixing circuit 6.
In the meantime, a microwave signal MS having a high frequency range, such as in the order of 12 GHz, is input to the amplifier 5 through the terminal 1 and further applied to the mixing circuit 6.
In the mixing circuit 6, the frequency difference between the signal MSa (about 12 GHz) and the signal SS~ (10.75 GHz) is obtained to produce an intermediate frequency signal IF
having a frequency in the range of 950 to 1450 MHz. This intermediate frequency signal IF is input to the amplifier 7 and further to the frequency distributor 11 through the terminal T1.
The amplified intermediate frequency signal IFa passes through the high pass filter lla, and is further applied through the line L to the high pass filter 12.
It is noted that the signal IFa will not pass through the low pass filters llb and 13.
The down converter DC thus requires only one cable line L
for its connection to the next stage component.
Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
Claims (6)
1. A down converter for converting a microwave signal to an intermediate frequency signal by the use of a standard signal having a frequency range of several to several tens of MHz, and for applying said intermediate frequency signal to a next stage component, said down converter comprising:
a mixing means for producing said intermediate frequency signal indicative of a frequency difference between said standard signal and said microwave signal; and a separator means comprising:
a first terminal for receiving said intermediate frequency signal;
a second terminal for producing and supplying said intermediate frequency signal to said next stage component and for receiving said standard signal from said next stage component;
a first filter means for separating said standard signal from said intermediate frequency signal; and a third terminal for producing said standard signal to said mixing means.
a mixing means for producing said intermediate frequency signal indicative of a frequency difference between said standard signal and said microwave signal; and a separator means comprising:
a first terminal for receiving said intermediate frequency signal;
a second terminal for producing and supplying said intermediate frequency signal to said next stage component and for receiving said standard signal from said next stage component;
a first filter means for separating said standard signal from said intermediate frequency signal; and a third terminal for producing said standard signal to said mixing means.
2. A down converter as claimed in Claim 1, wherein said second terminal further receives a DC current from said next stage, and wherein separator means further comprises a second filter means for separating said DC current, and a fourth terminal for producing said DC current.
3. A down converter as claimed in Claim 2, further comprising a DC supply means connected to said fourth terminal.
4. A down converter as claimed in Claim 1, wherein said second terminal is adapted for connection with a single line cable through which said intermediate frequency signal and said standard signal are transmitted in opposite directions.
5. A down converter as claimed in Claim 2, wherein said second terminal is adapted for connection with a single line cable through which said intermediate frequency signal and a combined signal of said standard signal and DC current are transmitted in opposite directions.
6. A down converter as claimed in Claim 1, wherein said mixing means comprises a phase synchronizing oscillation means for synchronizing said standard signal before being mixed with said microwave signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-300798 | 1990-11-05 | ||
| JP30069890A JPH04173617A (en) | 1990-11-06 | 1990-11-06 | Transporting device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2054859A1 CA2054859A1 (en) | 1992-05-06 |
| CA2054859C true CA2054859C (en) | 1995-10-10 |
Family
ID=17888008
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2054859 Expired - Fee Related CA2054859C (en) | 1990-11-05 | 1991-11-04 | Down converter for satellite communication system |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH04173617A (en) |
| CA (1) | CA2054859C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5344366B2 (en) * | 2008-09-05 | 2013-11-20 | 村田機械株式会社 | Transport system |
-
1990
- 1990-11-06 JP JP30069890A patent/JPH04173617A/en active Pending
-
1991
- 1991-11-04 CA CA 2054859 patent/CA2054859C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2054859A1 (en) | 1992-05-06 |
| JPH04173617A (en) | 1992-06-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH03190431A (en) | Homodyne reception system for cable television-converter and device thereof | |
| MY126348A (en) | Arrangement in a communication system | |
| US4395734A (en) | Remote muting for CATV/STV converters | |
| US5204984A (en) | Down converter for satellite communication system | |
| US4794458A (en) | Modulation device | |
| CA2054859C (en) | Down converter for satellite communication system | |
| US3944931A (en) | Multi-channel frequency converter having automatic control | |
| JPS63152231A (en) | Rf converter circuit | |
| US2397157A (en) | Wave length modulation system | |
| JP3411148B2 (en) | Bidirectional frequency converter | |
| WO1990004306A1 (en) | Signal transmission | |
| US4001729A (en) | Fm to am converter | |
| GB1026126A (en) | Improvements in or relating to circuit arrangements for use in colour-television receivers | |
| US4400726A (en) | Television signal distribution equipment for a cable network and including a stabilizer | |
| JP3450960B2 (en) | Frequency converter | |
| KR950005600B1 (en) | Multi-sound receiving apparatus for vcr | |
| JPS633266Y2 (en) | ||
| KR930002607B1 (en) | Tv channel modulation circuit | |
| JPH05315989A (en) | Frequency converter and band restoring device | |
| KR930010172B1 (en) | Remote voice control circuit for catv | |
| JP2001339223A (en) | Method and device for satellite radio wave reception | |
| JPH0628866Y2 (en) | Satellite receiver | |
| KR0144988B1 (en) | Tuning apparatus of double converting method for catv | |
| JPS6349962Y2 (en) | ||
| JPH11186853A (en) | Balance type mixer circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |