GB2518467A

GB2518467A - Signal converter

Info

Publication number: GB2518467A
Application number: GB1404483.8A
Authority: GB
Inventors: Che-Ming Wang
Original assignee: Wistron Neweb Corp
Current assignee: Wistron Neweb Corp
Priority date: 2013-09-23
Filing date: 2014-03-13
Publication date: 2015-03-25
Anticipated expiration: 2034-03-13
Also published as: TW201513562A; TWI560997B; GB201404483D0; GB2518467B

Abstract

A signal converter comprises a reception terminal 110, a first local oscillator LO1, a first mixer 130, a first divider 140, a second local oscillator LO2, a second mixer 131, a third local oscillator LO3 and a third mixer 132. Input terminals 110 (and 120) receive RF signals which have been transmitted with horizontal and vertical polarisation and which may occupy a frequency band from 290 MHz to 2,340 MHz. The first LO may operate at 9.94 GHz. The first mixer stage may convert the received RF signal to a frequency band from 7.6 GHz to 9.65 GHz. The converted RF signal is split and passes to the second LO / mixer (9.75 GHz) and to the third LO / mixer (10.6 GHz). The output of the second mixer may lie in a band from 1100 MHz to 2,150 MHz. The output of the third mixer may lie in a band from 950 MHz to 1950 MHz. The converter thus allows a conventional set-top box (STB) to receive signals in the range 290 MHz to 2340 MHz. The chosen IF frequencies reduce spurs in the 950-2150 MHz band.

Description

Signal Converter

Background of the Invention

1. Field of the invention

The present invention relates to a signal converter, and more particularly, to a signal converter which reduces spurs and has low power consumption.

2. Description of the Prior Prt

Satellite Broadcasting Television has been widely used all over the world. In traditional satellite broadcasting television, Quad or Quattro structure have been used for multiple subscribers. Regardless of low-noise block down-converter (LMB) for Quad structure with four subscribers or multiple subscriber structure composed of the Quattro structure and multiple switches, they are facing four-path signals (e.g. VL/VH/HL/HH) . Due to the overlapping among signals, four cables must be adopted in the system in order to individually input the signals to the set-top box or multiple switches.

The latest frequency band of 29O234O MHz is introduced for the LNB, which effectively transmit four-path signals (e.g. VL/VH/HL/HH) through two cables, reducing the number of the cables and the cost as well as provided for an IF based set-top box. However, the currently used set-top box is not able to receive the four-path signals of 29O234G MHz directly.

Slymmary of the invention It is therefore an objective of the present invention to provide a signal converter to convert a wide-band signal to a signal which can be received by a traditional set-top-box.

The present invention discloses a signal converter. The signal converter comprises a reception terminal, a first local oscillator, a first mixer, a first divider, a second local oscillator, a second mixer, a third local oscillator and a third mixer. The reception terminal is used for receiving a radio frequency (RF) signal which occupies a first frequency band. The first local oscillator is coupled to the reception terminal, and used for generating a first frequency. The first mixer is coupled to the first local oscillator, and used for convertinq the RE signal to a second frequency band. The first divider is coupled to the first mixer, and used for dividing the converted RE signal into a first signal and a second signal.

The second local oscillator is used for generating a second frequency. The second mixer is used for converting the first signal to a third frequency band according to the second frequency and the first signal. The third local oscillator is used for generating a third frequency. The third mixer is used for converting the second signal to a fourth frequency band according to the third frequency and the second signal.

The first frequency is 9.94Ghz; the second frequency is 9.75 GHz; the third frequency is 10.6GHz.

These and other obj ectves of the present invention will no doubt become obujous to tbse of ordinary skill in the art after: reading the following det.ai 1.ed description of the prefe.rred embodini.ent that is i.ilustrated in the various figures and drawings.

Er.ief rescr iutron of the Drawings FTG.l is an exemplary schematic diagram of a wireless system 1000.

FIG.2 is an exemplary schematic diagram of a signal converter 10.

FIG.3 is another example of the signal converter 10.

FIG.4 is an exemplary schematic diagram of a signal converter 20.

FIG.5 is an exemplary schematic diagram of a signal converter 30.

FIG. 6 is an exemplary schematic diagram of a signal converter 40.

Detailed Descrption Please refer to FIG.l, which is an exemplary schematic diagram of a wireless system 1000. The wireless system includes a wideband low-noise block down-converter (INB) 1200, a signal converter 1400 and a set-top-box (SIB) 1600. The signal converter 1400 is coupled between the IJNB 1200 and the set-top-box 1600 and used for converting the signal outputted from the LNB 1200 and then inputting the converted signal to the set-top-box 1600. The LNB 1200 can output a radio frequency (RF) signal composed of a vertical polarization and a horizontal polarization to the signal converter 1400.

Preferably, the signal converter 1400 transmits the signal to the set-top-box 1600 via four paths. The RF signal is around 2902340 MHz.

Please refer to FIG.2, which is an exemplary schematic diagram of a signal converter 10. The signal converter 10 can implement the signal converter 1400. The signal converter 10 includes reception terminals 110 and 112, multiple amplifiers 120, local oscillators L01, L02 and L03, multiple band-pass filter BPF1, BPF2, BPF3, BPF4, BPF5 and EPF6, multiple mixers 130, 131 and 132 and divider 140, switch module 150 and output terminals outputl, output2, output3 and output4. A radio frequency (RE) signal is transmitted to the signal converter via a vertical polarization and a horizontal polarization and received by the reception terminals 110 and 120. The RF signal is outputted from LNB (not shown in FIG.2) and a frequency band 31 of the RF signal is about 2902340 MHz. The multiple amplifiers 120 are used for amplifying the RF signal received from the front stage. The local oscillators L01, L02 and L03 generate frequencies fl, f2 and f3, respectively.

Wherein, the frequency fl is 9.94GHz; the frequency f2 is 9.75 GHz; the frequency f3 is 10.6 GHz. The mixer 130 is coupled to the local oscillator LOS and used for convertirg the RF signal to a frequency band 32 according to the RF signal and the frequency fl. The frequency band B2 is about 7.6GHz-9.65GHz. The divider 140 is coupled to the mixer 130 and used for dividing the RF signal into a first signal and a second signal. The mixer 131 is used for converting the first signal to a frequency band 33 according to the first signal and the frequency f2 (9.750Hz). The freguency band 33 is about 1100 MHz215O MHz. The mixer 132 is used for converting the second signal to a freqilency band B4 according to the frequency f3 (10.6 0Hz) and the second signal. The frequency band 34 is around 950 MHz"4950 MHz. The frequency bands 33 and 34 are the frequency bands which can be received by a traditional set-top-box. The band-pass filter BPF1 has the same bandwidth as the frequency band 31, which filters out the noise outside of the freguency B1. The band-pass filter BPF2 is coupled to the mixer 130. The band-pass filter BPF2 has the same frequency band as the frequency band 32, which filters out the noise outside of the frequency band 32. The band-pass filter BPF4 is coupled to the divider 140 and the mixer 132. The band-pass filter BPF4 has the same frequency band as the second signal.

The band-pass filter 3PF3 is coupled to the divider 140 and the mixer 131. The band-pass filter BPF3 has the same frequency band as the first signal. The band-pass filter BPF5 is coupled to the mixer 132. The band-pass filter BPF5 has the same frequency band as the freguency band 34 (950MHz4950MHz) which filters out the noise outside of the frequency band 34.

The band-pass filter BPF6 is coupled to the mixer 131. The band-pass filter BPF6 has the same frequency as the frequency bandB3 (1100MHz"2150MHz), which filters out the noise outside of the frequency band 33. Preferably, the abovementioned mixers 130, 131 and 132 can be implemented by Schcttky dicdes.

The switch module 150 includes switches SWl and 5W2 which are coupled to the output terminals outputl and output2 and the output terminals output3 and output 4, respectively. Thus, the signal converter 10 can convert the RF signal (290 MHz-2340 MHz) to the frequency bands 33 (1100 MHz2150 MHz) and B4 (950 MHzl950 MHz) which can be outputted to and received by the traditional set-top-box. Please note that the signal converter 10, besides the band-pass filters EFF1, BPF2, 3PE3, BPF4, BPF5 and BPF6, may include more band-pass filters or high-pass filters and low-pass filters accordinq to a practical requirement, not limited herein. Please refer to FIG.3, which is another example of the signal converter 10.

As shown in FTG.3, the dividers 141, 142 and 143, and the band-pass filters BPF7, BPF8 and BPF9 can be added between the local oscillators Lol, L02, L03 and the mixers 130, 131, 132. The detailed description of FIG.3 can be found above, and thus omitted herein.

To be more specific, the LMB outputs the RF signal cccupying the frequency band 31 (2902340 MHz) to the signal converter through vertical polarization and horizontal polarization.

Then, the amplifiers 120 of the signal converter 10 amplify the RF signal and output the amplified RE signal to the mixer 130. The mixer 130 converts the RE signal up to the frequency band 32 (7.69.65 GHz) by using the frequency fl generated by the local oscillator hal. The frequency band 32 falls within the frequency band X (812 GHz) regulated by IEEE standard.

The divider 140 divides the up-converted RE signal into the first signal and the second signal. The first signal is about 7.68.65 GHz while the second signal is about 8.65-9.65 GHz.

The mixer 131 converts the first signal down to the frequency band B3 (l1002150 MHZ) by using the frequency f2 (9.75 GHz) generated by the local oscillaror L02. The mixer 132 converts the second signal down to the frequency band B4 (9501950 MHz) by using the frequency f3 (10.6 GHz) generated by the local oscillator L03. Such that the signal converter 10 converts the RF signal (2902340 MHz) outpntted from the LNB to the traditional four-path signals (i.e. VL/VH/HL/HH) and outputs the traditional four-path signals to the traditional set-top-box. Since the frequencies generated by the local oscillators JUO1, L02, L03 and 1J04 are 9.94 GHz, 9.75 GHz and 10.6 GHz, it is less likely that the spurs generated by the local oscillators fall within the frequency band 950MHz2150 MHz, as shown in table 1.

tOll 11tJ Ø1: Ø$ :j5j 4$ :$,a M.Ø --o i,l -si 1. - WI 041. ------ 102 W' 43U 43 l0t 13 080 (1 II -----at.l41o13'" C:' : . I 1-1 aiL II) (45 KilO S.Z I I I I SJM.3 122:311071022 004 10.3? 37 1° 1:-1-1 aim-I' 1371 1135 1538 037 1373 5115 -87 3 1 37*3 31,2 1192 123 10,5 198 53 -- 4*01 1 211 1. 1*101 2216 1955 2023 18.30 9131 11151 7% 1 -I I - 33 0 2925224 1912 195 138 938 9,75 7.2 -*355 4*Th 4Z1 21 325531.8 2252 329 21.2 1258 13.15 10.6 204 1 (8 377: 3,J3 3:1.295.2 302 *28,5 1555 *2045 1711 955 107 72: Lm4ar *.n 315 siss7 scr.s 27,55 1555 1%: 1695 599: 905 6,55 -os -aim I 13(1 13' 91 3312 335 31.8 2318 23.55 212 1321 1'l 10.6 31 4'

Table 1 (in GHz)

According to Table 1, the local oscillators LOl, L02 and LOS only generates spurs at 1.32 GHz, 1.7 GHz and 1.98GHz.

Neither the in-bad spurious caused by the mixers nor the overlapping due to up-conversion is found. In this case, the high isolation mixer is no longer required. Apart from that, another advantage is low power consumption. Compared to the currently used frequency conversion in L/S/C frequency bands, the signal converter 10 in the examples of the present disclosure converts the RF signal to the X frequency band by using the local oscillator LO1 (9.94 0Hz), and then coverts the down-converted RF signal back to the four-path signals (VL/VH/HL/HH) by using the local oscillators 502 and 503 (9.75 GHz and 10.6GHZ) . Since the examples of the present disclosure avoid the frequency conversion in s/s/c frequency bands, the prohibitive and high power consuming frequency conversion chip is no longer needed, which further saves the extra power consumption of about 500-100 mA generated by the frequency conversion chip. Besides, the input and output isolation for up-conversion and down-conversion chips must be above 40 dB in the prior art, this rising the cost and difficulty for the chip design. The signal converter 10 according to examples

of the present disclosure can solve that problem.

Please refer to FTG.4, which is another exemplary schematic diagram of a signal converter 20. The basic structure of the signal converter 20 is similar to the one of the signal converter 10. Thus the same reference numbers indicate identical or functionally similar elements. The difference between the signal converter 10 and the signal converter 20 is that the switch module 150 in the signal converter 20 has two output paths while the switch module 140 in the signal converter 10 has four output paths. In this situation, the signal converter 20 includes only the switch OWl and output terminals outputS and output2.

In other hand, more electronic components can be added in the signal converter 10 to support the new set-top-box or wideband set-top-box. Please refer to FIG.5, which is still another exemplary schematic diagram of a signal converter 30.

The basic structure of the signal converter 30 is similar to the one of the signal converter 10. Thus the same reference numbers indicate identical or functionally similar elements.

The difference between the signal converter 10 and the signal converter 30 is that the signal converter 30 includes a divider and a switch module 170. The divider 160 is coupled to the reception terminals 110 and 112 and used for receiving the RF signals from the reception terminals 110 and 112, individually. The switch module 170 includes switches SW3 and SW4. The switch module 170 is coupled to the divider 160 and the switch module 150, and used for switching the switches SW3, SW4, SW5, and SW6 to output the RF signal or the down-converted first signal and the second signal according to a signal S sent from an electronic device. The signal S can be a digital satellite equipment control (DiSEqC) , a frequency-shifting keying (FSK) or includes voltage information. The signal S indicates that the electronic device is a traditional set-top-box or a wide band set top box. When the signal S indicates the set top box is a traditional set top box, the switch module 170 switches the switches S SW3, SW4, SW5, and SW6 to output the down-converted first signal and second signal to the output terminals outputl, output2, output 3, and output4. When the signal S indicates the set top box is a wide band set top box, the switch module 170 switches the switches SW3, SW4, SW5, and SW6 to output the RF signal to the output terminals outputi, output2, output 3, and output4.

Please refer to FIG.6, which is yet another exemplary schematic diagram of a signal converter 40. The basic structure of the signal converter 40 is similar to the one of the signal converter 10. Thus the same reference numbers indicate identical or functionally similar elements. The difference between the signal converter 10 and the signal converter 40 is that the signal converter 40 includes a switch module 180 and a switch module 190. The switch module 180 includes switches SW7 and SW8 coupled to the reception terminal 110 and 112, respectively. The switch module 180 is used for switching the switches 5W7 and 5W8 to output the RF signal to different terminals. The switch module 190 includes switches SW9 and SWiG, which are coupled to the switch modules and 180, respectively. The switch module 190 is used for switching the switches SW9 and SW1O to output the RF signal or the down-converted first signal and second signal according to the signal S. When the signal S indicates the set top box is a traditional set top box, the switch module 180 switches the switches SW7 and SW8 to output the RF signal to the output terminals outputl and output2. When the signal S indicates the set top box is a wide band set top box, the switch module switches the switches 5W7 and SW8 to output the RF signal to the switch 190. The switch 190 switches the switches SW9 and SW1C to output the RF signal to the output terminals outputl and output2.

To sun up, the signal converter outputs the RF signal to the first mixer after amplifying the RE signal through the amplifier and then uses the local oscillator of 9.94 GHz to up-convert the RE signal to 7.6-9.65 GHz. The divider is used to divide the up-converted RF signal into the first signal (8.659.65 GHz) and the second signal (7.68.65 5Hz). The first signal and the second signal are down-converted back to 950il950 MHz and 1l00-2150 MHz, respectively, by using the local oscillators of 10.6 5Hz and 9.75 5Hz. Finally, the down-converted signals are received by the currently used set top box through the switch module. To put it simply, the signal converter converters the RE signal of 2902340 MHz into four-path signals (VL/VH/HL/HH) which could be received by the currently used set top box.

Those skilled in the art. will readily observe that nume.rous rn.odni.cat.ionb and alterations of the device arid rnethcd may be made while retaining the teachirLgs of the irozentlon.

Accordingly, the above disclosure shoul!d he construed as limited only by the--metes and bcunds of the appended claims.

Claims

Cl aims What is claimed is: 1. A signal converter comprising: a reception terminal for receiving a radio frequency (RF) signal which occupies a first frequency band; a first local oscillator coupled to the reception terminal, for generating a first frequency; a first mixer coupled to the first local oscillator, for converting the RB' signal to a second frequency band according to the RB' signal and the first frequency; a first divider coupled to the first mixer, for dividing the converted RB' signal into a first signal and a second signal; a second local oscillator, for generating a second frequency; a second mixer, for converting the first signal to a third frequency band according to the second frequency and the first signal; a third local oscillator, for generating a third frequency; and a third mixer, for converting the second signal to a fourth frequency band according to the third frequency and the second signal; wherein, the first frequency is 9.94GHz; the second frequency is 9.75 GFIz; the third frequency is 10.6GHz.
2. The signal converter of claim 1, wherein the first frequency band is about fron 290 MHz to 2340 MHz; the second frequency band is about from 7.6 GHz to 9.65 GUs; the third frequencybandis about fromllOOMHz to 2150MHz; the fourth frequency band is about from 950 MHz to 1950 MHz. ii
3. The signal converter of claim 1 further comprising: an ampiifier coupled to the reception terminal, for amplifying the RF signal; a first band-pass filter coupled the amplifier, wherein a bandwidth of the first band-pass filter is equal to the first frequency band; a second band-pass filter coupled to the first mixer, wherein a bandwidth of the second band-pass filter is equal to the second frequency band; a third band-pass filter coupled to the first divider, wherein a bandwidth of the third band-pass filter is equal to a bandwidth of the second signal; a fourth band-pass filter coupled to the first divider, wherein a bandwidth of the fourth band-pass filter is equal to a bandwidth of the first signal; a fifth band-pass filter coupled to the third mixer, wherein a bandwidth of the fifth band-pass filter is equal to the fourth frequency band; and a sixth band-pass filter coupled to the second mixer, wherein a bandwidth of the sixth band-pass filter is equal to the third frequency band.
4. The signal converter of claim 1, wherein each of the first mixer, the second mixer and the third mixer is implemented by a Schottky diode.
5. The signal converter of claim 1 further comprising: a plurality of output terminals; and a first switch module coupled to the second mixer and the third mixer, for switching between the first signal and the second signal to be outputted to the plurality of output terminals.
6. The signal converter of claim 5 further comprising: a second divider coupled to the reception terminal, for dividing the RF signal; and a second switch module coupled to the second divider and the first switch module, for outputting the RE signal or the down-converted first signal and the second signal according to a signal from an electronic device.
7. The signal converter of claim 6, wherein the signal indicates that the electronic device is a set-top-box or a wide-band set-top-box.
8. The signal converter of claim 6, wherein the signal is a digital satellite equipment control (DiSEqC) , a frequency-shifting keying (ESK) or the signal includes voltage information.
9. The signal converter of claim 5 further comprising: a second switch module coupled to the reception terminal, for outputting the RE signal to different input terminals; and a third switch module coupled to the first switch module and the second switch module, for outputting the RE signal or the first signal and the second signal according to a signal from an electronic device.
10. The signal converter of claim 9, wherein the signal indicates that the electronic device is a traditional set-top-box or a wide-band set-top-box.

ii. The signal converter of claim 9, wherein the signal is a digital satellite equipment control (DiSEgC) , a frequency-shifting keying (FSK) or the signal includes voltage information.Amendments to the claims have been filed as follows Claims What is claimed is: 1. A signal converter comprising: a reception terminal for receiving a radio frequency (RE) signal which occupies a first frequency band; a first local oscillator, for generating a first frequency; a first mixer coupled to the first local oscillator, for converting the RE signal to a second frequency band accordinq to the RE signal and the first frequency; a first divider coupled to the first mixer, for dividing the converted RE signal into a first signal and a second signal; a second local oscillator, for generating a second frequency; a second mixer, for converting the first signal to & third frequency band according to the second frequency and the first signal; a third local oscillator, for generating a third frequency; C) and a third mixer, for converting the second signal to a fourth frequency band according to the third frequency and the second signal; wherein, the first frequency is 9.94GHZ; the second freguency is 9.75 GHz; the third frequency is 10.6GHz.2. The signal converter of claim 1, wherein the first frequency band is substantially from 290 MHz to 2340 MHz; the second frequency band is substantially from 7.6 GHz to 9.65 GHz; the third frequency band is substantially from 1100 MHz to 2150 MHZ; the fourth frequency band is substantially from 950 MHz to 1950 MHz.3. The signal converter of claim 1 further comprising: an amplifier coupled to the reception terminal, for amplifying the RF signal; a first band-pass filter coupled the amplifier, wherein a bandwidth of the first band-pass filter is equal to the first frequency band; a second band-pass filter coupled to the first mixer, wherein a bandwidth of the second band-pass filter is equal to the second frequency band; a third band-pass filter coupled to the first divider, wherein a bandwidth of the third band-pass filter is equal to a bandwidth of the second signal; a fourth band-pass filter coupled to the first divider, wherein a bandwidth of the fourth band-pass filter is equal to a bandwidth of the first signal; a fifth band-pass filter coupled to the third mixer, wherein a bandwidth of the fifth band-pass filter is equal to the fourth frequency band; and a sixth band-pass filter coupled to the second mixer, wherein a bandwidth of the sixth band-pass filter is equal to the 0) third frequency band. (44. The signal converter of claim 1, wherein each of the first mixer, the second mixer and the third mixer is implemented by a Schottky diode.5. The signal converter of claim 1 further comprising: a plurality of output terminals; and a first switch module coupled to the second mixer and the third mixer, for switching between the first signal and the second signal to be outputted to the plurality of output terminals.6. The signal converter of claim 5 further comprising: a second divider coupled to the reception terminal, for dividing the RE signal; and a second switch module coupled to the second divider and the first switch module, for outputting the RE signal or the down-converted first signal and the second signal according to a signal from an electronic device.7. The signal converter of claim 6, wherein the signal indicates that the electronic device is a set-top-box or a wide-band set-top-box.8. The signal converter of claim 5 further comprising: a second switch module coupled to the reception terminal, for outputting the RE signal to different input terminals; and a third switch module coupled to the first switch module and the second switch module, for outputting the RE signal or the first signal and the second signal according to a signal from an electronic device.Q) 9. The signal converter of claim 8, wherein the signal indicates that the electronic device is a traditional set-top-box or a wide-band set-top-box.10. The signal converter of claim 6 or claim 8, wherein the signal is a digital satellite equipment control (DiSEqC), a frequency-shifting keying (P3K) or the signal includes voltage information.