JP4255436B2 - Converter for satellite broadcasting reception - Google Patents

Description

  The present invention relates to a satellite broadcast receiving converter, and more particularly to a satellite broadcast low noise converter (hereinafter referred to as “LNB”).

  First, a typical satellite broadcast receiving system will be described. The LNB is attached to the satellite broadcast receiving antenna. It converts the weak radio wave arriving from the satellite into the intermediate frequency (IF frequency) of the 1 GHz band, and amplifies it with low noise, and then connects. The so-called DBS tuner is supplied with a low noise and a sufficient level of signal. The DBS tuner processes this signal supplied from the coaxial cable by an internal circuit and supplies it to the television receiver.

  Next, a conventional configuration example of the LNB will be described with reference to FIGS. FIG. 2 is an electrical configuration diagram of a conventional LNB. FIG. 3 is an enlarged view of a part of FIG. 2 and is a diagram for explaining the operation around the band changeover switch (band transrating switch; BT SW) 14 in FIG. 3, the same parts as those in FIG. 2 are denoted by the same reference numerals.

  The LNB shown in FIG. 2 can receive broadcast radio waves from a first satellite (not shown) and broadcast radio waves from a second satellite (not shown). In addition, two output ports (an output port 20 and an output port 50 described later) connected to a tuner (not shown) are provided. In other words, it is a two-satellite reception and two-output type LNB.

  A 12 GHz band signal coming from a first satellite (not shown) is received by an antenna probe 30 in the waveguide, and a left-hand polarized signal (hereinafter referred to as “L1 polarized signal”) is transmitted from the antenna probe 30 to the line 1. Is extracted, and a right-hand polarized signal (hereinafter referred to as “R1 polarized signal”) is extracted from the line 2.

  These polarization signals (L1 polarization signal and R1 polarization signal) included in the broadcast radio wave from the first satellite are both signals in the 12.2 to 12.7 GHz band, and are low noise amplifiers (hereinafter referred to as “ L1 polarization signal is transmitted to a bandpass filter (hereinafter referred to as “BPF”) 4, and R1 polarization signal is transmitted to BPF 5. The LNA 3 includes amplifiers 3a and 3b that amplify the L1 polarization signal and amplifiers 3c and 3d that amplify the R1 polarization signal. Each of the BPFs 4 and 5 serves to remove a signal in the image frequency band.

  The signals that have passed through the BPFs 4 and 5 are transmitted to the mixers 6 and 7, respectively. The mixer 6 outputs an intermediate frequency signal having a frequency difference between the 14.35 GHz local oscillation signal supplied from the local oscillator 8 and the input L1 polarization signal. Therefore, the frequency band of the intermediate frequency signal output from the mixer 6 is (14.35 GHz-12.2 GHz) to (14.35 GHz-12.7 GHz) = 1650 MHz to 2150 MHz.

  On the other hand, the mixer 7 outputs an intermediate frequency signal having a frequency difference between the 11.25 GHz local oscillation signal supplied from the local oscillator 9 and the input R1 polarization signal. The frequency band of the intermediate frequency signal output from the mixer 7 is (12.2 GHz-11.25 GHz) to (12.7 GHz-11.25 GHz) = 950 MHz-1450 MHz.

  That is, the mixer 6 converts the received L1 polarization signal into a high frequency band and outputs it, and the mixer 7 converts the received R1 polarization signal into a low frequency band and outputs it.

  Hereinafter, in this specification, the frequency band of 1650 MHz to 2150 MHz is referred to as “high frequency side band”, and the frequency band of 950 MHz to 1450 MHz is referred to as “low frequency side band”.

  The output signal of the mixer 6 is supplied to the IF mixing circuit (synthesizer) 12 through a high-pass filter (hereinafter referred to as “HPF”) 10 that passes the high frequency side band (1650 MHz to 2150 MHz). The signal is supplied to an IF mixing circuit (synthesizer) 12 through a low-pass filter (hereinafter referred to as “LPF”) 11 that passes a low-frequency side band (950 MHz to 1450 MHz).

  In the IF mixing circuit 12, the output signal of the mixer 6 and the output signal of the mixer 7 are combined (combined), and further amplified by the IF amplifier 13 so as to have appropriate noise characteristics and gain characteristics. The output signal of the IF amplifier 13 is a signal in which the L1 polarization signal converted into the high frequency side band (High Band) and the R1 polarization signal converted into the low frequency side band (Low Band) coexist. (See FIG. 3). The output signal of the IF amplifier 13 is given to one input terminal of the band change switch 14.

  Further, a 12 GHz band signal coming from the second satellite (not shown) is received by the antenna probe 60 in the waveguide, and a left-handed polarization signal (hereinafter referred to as “L2 polarization signal”) is transmitted from the antenna probe 60 to the line 31. And a right-hand polarized signal (hereinafter referred to as “R2 polarized signal”) is extracted from the line 32.

  These polarization signals (L2 polarization signal and R2 polarization signal) included in the broadcast wave from the second satellite are both signals in the 12.2 to 12.7 GHz band, and after being amplified by the LNA 33, The L2 polarization signal is transmitted to the BPF 34, and the R2 polarization signal is transmitted to the BPF 35. The LNA 33 includes amplifiers 33a and 33b that amplify the L2 polarization signal and amplifiers 33c and 33d that amplify the R2 polarization signal. Each of the BPFs 34 and 35 serves to remove a signal in the image frequency band.

  The signals that have passed through the BPFs 34 and 35 are transmitted to the mixers 36 and 37, respectively. The mixer 36 outputs an intermediate frequency signal having a frequency difference between the 14.35 GHz local oscillation signal supplied from the local oscillator 8 and the input L2 polarization signal. Therefore, the frequency band of the intermediate frequency signal output from the mixer 36 is (14.35 GHz-12.2 GHz) to (14.35 GHz-12.7 GHz) = 1650 MHz to 2150 MHz (high frequency side band).

  On the other hand, the mixer 37 outputs an intermediate frequency signal having a frequency difference between the 11.25 GHz local oscillation signal supplied from the local oscillator 9 and the input R2 polarization signal. The frequency band of the intermediate frequency signal output from the mixer 37 is (12.2 GHz-11.25 GHz) to (12.7 GHz-11.25 GHz) = 950 MHz to 1450 MHz (low frequency side band).

  In other words, the mixer 36 converts the received L2 polarization signal into a frequency band on the high frequency side and outputs it, and the mixer 37 converts the received R2 polarization signal into a frequency band on the low frequency side and outputs it.

  The output signal of the mixer 36 is supplied to the IF mixing circuit (synthesizer) 42 via the HPF 40 that passes the high frequency side band (1650 MHz to 2150 MHz), and the output signal of the mixer 37 is the low frequency side band (950 MHz to To the IF mixing circuit (synthesizer) 42 through the LPF 41 that passes the band of 1450 MHz.

  In the IF mixing circuit 42, the output signal of the mixer 36 and the output signal of the mixer 37 are combined (combined), and further amplified by the IF amplifier 43 so as to have appropriate noise characteristics and gain characteristics. The output signal of the IF amplifier 43 is a signal in which the L2 polarization signal converted to the high frequency side band (High Band) and the R2 polarization signal converted to the low frequency side band (Low Band) coexist. (See FIG. 3). The output signal of the IF amplifier 43 is given to the other input terminal of the band change switch 14.

  The band changeover switch 14 includes a first output terminal 14a used as an output on the high frequency side, a second output terminal 14b used as an output on the low frequency side, a third output terminal 14c used as an output on the high frequency side, And a fourth output terminal 14d used as an output on the frequency side.

  The types of signals output from the band change switch 14 will be described with reference to FIG. FIG. 4A shows the types of signals output from the first output terminal 14a and the types of output signals of the HPF 15 described later. FIG. 4B shows the types of signals output from the second output terminal 14b and the types of output signals of the LPF 16 described later. FIG. 4C shows the types of signals output from the third output terminal 14c and the types of output signals of the HPF 45 described later. FIG. 4D shows the types of signals output from the fourth output terminal 14d and the types of output signals of the LPF 46 described later.

  As shown in FIG. 4A, the band changeover switch 14 synthesizes the L1 polarization signal converted into the high frequency side band and the R1 polarization signal converted into the low frequency side band from the first output terminal 14a. A signal (hereinafter referred to as “synthetic signal α”), an R1 polarized signal converted into a high frequency side band and an L1 polarized signal converted into a low frequency side band were synthesized ( Co-existing signal (hereinafter this signal is referred to as “combined signal β”), the L2 polarized signal converted to the high frequency side band and the R2 polarized signal converted to the low frequency side band were combined (coexisted) ) Signal (hereinafter, this signal is referred to as “synthetic signal γ”), and the R2 polarized signal converted to the high frequency side band and the L2 polarized signal converted to the low frequency side band are combined (coexisted). One of the signals (hereinafter, this signal is referred to as “synthetic signal δ”) One of the signals alternatively selects and outputs.

  This selection is made on the basis of a control signal from a control unit 21 composed of a microcomputer or the like, and the control signal is based on a pulse signal (selection signal) from an external tuner (not shown) connected to the output port 20. Created. That is, a tuner (not shown) connected to the output port 20 can arbitrarily select a signal output from the output terminal 14a as one of the combined signals α, β, γ, and δ.

  Similarly, as shown in FIG. 4B, the band changeover switch 14 selectively selects one of the composite signals α, β, γ, and δ from the second output terminal 14b. Output. This selection is also made based on a control signal from the control unit 21, and the control signal is also created based on a pulse signal (selection signal) from an external tuner (not shown) connected to the output port 20. That is, a tuner (not shown) connected to the output port 20 can arbitrarily select a signal output from the second output terminal 14b as one of the combined signals α, β, γ, and δ.

  Similarly, as shown in FIG. 4 (c), the band changeover switch 14 selectively selects one of the composite signals α, β, γ and δ from the third output terminal 14c. Output. This selection is also made based on a control signal from the control unit 21, and the control signal is created based on a pulse signal (selection signal) from an external tuner (not shown) connected to the output port 50. That is, a tuner (not shown) connected to the output port 50 can arbitrarily select a signal output from the third output terminal 14c as one of the combined signals α, β, γ, and δ.

  Similarly, as shown in FIG. 4D, the band changeover switch 14 selectively selects one of the composite signals α, β, γ, and δ from the fourth output terminal 14d. Output. This selection is also made based on a control signal from the control unit 21, and the control signal is also created based on a pulse signal (selection signal) from an external tuner (not shown) connected to the output port 50. That is, a tuner (not shown) connected to the output port 50 can arbitrarily select a signal output from the fourth output terminal 14d as one of the combined signals α, β, γ, and δ.

  In order to select the signal output from each output terminal 14a, 14b, 14c, 14d as one of four composite signals (synthesized signals α, β, γ, and δ) for each output terminal, for example, control The control signal from the unit 21 is composed of a digital signal of 8 bits (2 bits × 4 output terminals). The band change switch 14 is configured by, for example, an integrated circuit (IC).

  The output signal of the band changeover switch 14 output from the first output terminal 14a passes the component of the high frequency side band (1650 MHz to 2150 MHz) to the HPF 15 for attenuating the component of the low frequency side band (950 MHz to 1450 MHz). Given. As a result, when the composite signals α, β, γ, and δ are output from the first output terminal 14a, the HPF 15 has an R1 polarization signal, an L1 polarization signal, and R2 as shown in FIG. The polarization signal and the L2 polarization signal are removed.

  The output signal of the band changeover switch 14 output from the second output terminal 14b passes the component of the low frequency side band (950 MHz to 1450 MHz) to the LPF 16 for attenuating the component of the high frequency side band (1650 MHz to 2150 MHz). Given. As a result, when the combined signals α, β, γ, and δ are output from the second output terminal 14b, the LF polarization signal, the R1 polarization signal, and the L2 are respectively output from the LPF 16 as illustrated in FIG. 4B. The polarization signal and the R2 polarization signal are removed.

  The output signal of the band changeover switch 14 output from the third output terminal 14c passes the high frequency side band (1650 MHz to 2150 MHz) component and passes to the HPF 45 for attenuating the low frequency side band (950 MHz to 1450 MHz) component. Given. As a result, when the combined signals α, β, γ, and δ are output from the third output terminal 14c, as shown in FIG. 4 (c), the HPF 45 performs the R1 polarization signal, the L1 polarization signal, and the R2 respectively. The polarization signal and the L2 polarization signal are removed.

  The output signal of the band change switch 14 output from the fourth output terminal 14d passes through the low frequency side band (950 MHz to 1450 MHz) component and passes to the LPF 46 for attenuating the high frequency side band (1650 MHz to 2150 MHz) component. Given. As a result, when the composite signals α, β, γ, and δ are output from the fourth output terminal 14d, the LF polarization signal, the R1 polarization signal, and the L2 are respectively output from the LPF 46 as illustrated in FIG. The polarization signal and the R2 polarization signal are removed.

  The output signal of the HPF 15 and the output signal of the LPF 16 are both supplied to the IF mixing circuit (synthesizer) 17 and combined (combined), then amplified by the IF amplifier 18 and led to the output port 20 via the capacitor 19. The The output port 20 is connected to an input terminal of a tuner (not shown).

  Both the output signal of the HPF 45 and the output signal of the LPF 46 are supplied to an IF mixing circuit (synthesizer) 47 and synthesized (combined), then amplified by an IF amplifier 48 and led out to an output port 50 via a capacitor 49. The The output port 50 is connected to an input terminal of a tuner (not shown).

  A DC voltage is supplied from the tuner side to at least one of the output port 20 and the output port 50. The DC voltage is made constant by a regulator (not shown) and supplied as a power supply voltage to each circuit such as LNA 3 in the LNB. Further, in order to transmit a pulse signal (selection signal) transmitted from the tuner side to the control unit 21, the output port 20 and the control unit 21 are connected, and the output port 50 and the control unit 21 are connected.

  Since the LNB in FIG. 2 is a two-satellite reception and two-output type LNB, each output signal from the output port 20 and the output port 50 is divided into two, and two tuners (not shown) are connected to each output port. In this case, an arbitrary polarization signal from an arbitrary satellite can be used in each tuner (each of four tuners in total). This will be explained further.

  Consider a case where two tuners (not shown), tuner A and tuner B, are connected to the output port 20. For example, when tuner A desires to receive a channel included in the L1 polarization signal, and tuner B desires reception of a channel included in the R2 polarization signal, tuner A instructs the control unit 21 to “ Transmits a pulse signal (selection signal) indicating that “the reception of the channel included in the L1 polarization signal is desired”, and the tuner B desires to receive the “channel included in the R2 polarization signal” to the control unit 21. "Pulse signal" (selection signal) is transmitted. The pulse signals from the tuners A and B to the control unit 21 are transmitted at different timings (in a time division manner).

  The control unit 21 gives a control signal corresponding to the pulse signals (selection signals) from the tuners A and B to the band change switch 14. Then, the band changeover switch 14 outputs the combined signal α from the first output terminal 14a and also outputs the combined signal γ from the second output terminal 14b. Since the low frequency side band of the composite signal α from the first output terminal 14a is removed and the high frequency side band of the composite signal γ from the second output terminal 14b is removed, the output port 20 converts to the high frequency side band. The combined L1 polarization signal and the R2 polarization signal converted to the low frequency side band are combined (coexisted). Since the signals from the output port 20 are received by the tuners A and B, the above-mentioned hopes of the tuners A and B are fulfilled.

  Thus, each tuner connected to the output ports 20 and 50 can use any polarization signal from any satellite.

  In Patent Document 1 below, a slot that matches the frequency of a signal that is not desired to be received among the input signal components is provided on the short surface of the LNB input waveguide, and the reception is performed at the rear of the slot. An LNB device having a series resonant circuit for absorbing undesired signals is disclosed.

JP-A-11-330810

  However, in the conventional configuration example shown in FIG. 2, if the attenuation amount of the HPF 15 and the LPF 16 arranged at the subsequent stage of the band change switch 14 is not sufficient, an unnecessary signal is output as spurious. For example, if the attenuation amount of the HPF 15 is not sufficient, the low-frequency side band signal from the first output terminal 14a side is superimposed on the signal from the second output terminal 14b side and output as spurious.

  Similarly, if the attenuation amount of the HPF 45 and the LPF 46 arranged at the subsequent stage of the band change switch 14 is not sufficient, an unnecessary signal is output as a spurious signal.

  Another object of the LNB device described in Patent Document 1 is to prevent a signal having a frequency that is not desired to be received from being picked up by a waveguide probe so that a necessary signal can be received in good condition. However, it does not solve the above-mentioned problems of the conventional LNB having a band switching (band transrating) function.

  In view of the above points, the present invention provides a satellite broadcast receiving converter having a band switching (band transrating) function, which can reduce unnecessary signal components and suppress spurious generation. The purpose is to provide.

In order to achieve the above object, a first satellite broadcast receiving converter according to the present invention converts a first polarization signal included in a broadcast radio wave from a first satellite into a first frequency band and outputs the first polarized wave. 1 mixer, a second mixer for converting the second polarization signal contained in the broadcast radio wave from the first satellite to a second frequency band on the lower frequency side than the first frequency band, and outputting the second polarization signal from the second satellite A third mixer that converts the third polarization signal included in the broadcast radio wave to the first frequency band and outputs it, and a fourth polarization signal included in the broadcast radio wave from the second satellite is converted to the second frequency band. A first mixer that receives a signal obtained by combining the output signal of the first mixer and the output signal of the second mixer, and the output signal of the third mixer and the output signal of the fourth mixer. A first output terminal having a second input terminal for receiving the synthesized signal; , A first combined signal having a second output terminal, a third output terminal, and a fourth output terminal, and combining the first polarization signal in the first frequency band and the second polarization signal in the second frequency band; A second synthesized signal obtained by synthesizing the second polarization signal in the first frequency band and the first polarization signal in the second frequency band, the third polarization signal in the first frequency band, and the fourth polarization signal in the second frequency band. And a third synthesized signal, and a fourth synthesized signal obtained by synthesizing the fourth polarized signal in the first frequency band and the third polarized signal in the second frequency band. A band selector switch for selecting each output terminal of the first to fourth output terminals according to a selection signal supplied from the outside, and outputting the selected signals from each output terminal of the first to fourth output terminals; , A high pass filter for attenuating the second frequency band component in the output signal from the first output terminal. And a trap circuit for attenuating a component of the second frequency band in the output signal from the first output terminal, and a high-pass filter and a trap circuit. A synthesizer that synthesizes an output signal from the first output terminal in which the frequency band component is attenuated and a signal based on the output signal from the second output terminal, and the first polarization signal in the second frequency band The second polarization signal in the first frequency band, the third polarization signal in the second frequency band, the fourth polarization signal in the first frequency band, the second combined signal, and the fourth combined signal in the band changeover switch It is generated .

  When the second frequency band component in the output signal from the first output terminal is an unnecessary signal component, it is desirable to remove the unnecessary signal component as much as possible before supplying it to the synthesizer. Since the trap circuit is provided in addition to the high-pass filter, the output signal from the first output terminal can be supplied to the synthesizer after the second frequency band component is sufficiently attenuated. Thereby, in the combiner, unnecessary signal components superimposed on the signal based on the output signal from the second output terminal are reduced, and as a result, the occurrence of spurious is suppressed.

In order to achieve the above object, a second satellite broadcast receiving converter according to the present invention converts a first polarization signal included in a broadcast radio wave from the first satellite into a first frequency band and outputs the first polarization signal. A first mixer that converts the second polarization signal contained in the broadcast radio wave from the first satellite into a second frequency band lower than the first frequency band, and a second satellite. A third polarization signal included in the broadcast radio wave from the first satellite is converted into a first frequency band and output; and a fourth polarization signal included in the broadcast radio wave from the second satellite is converted into the second frequency band. A fourth mixer that converts and outputs the first mixer, a first input terminal that receives a signal obtained by combining the output signal of the first mixer and the output signal of the second mixer, and the output signal of the third mixer and the output signal of the fourth mixer And a second input terminal for receiving a combined signal, and a first output A first combined signal having a terminal, a second output terminal, a third output terminal, and a fourth output terminal, and combining the first polarization signal in the first frequency band and the second polarization signal in the second frequency band; A second synthesized signal obtained by synthesizing the second polarization signal in the first frequency band and the first polarization signal in the second frequency band; the third polarization signal in the first frequency band; and the fourth polarization in the second frequency band. One of the third synthesized signal obtained by synthesizing the signal and the fourth synthesized signal obtained by synthesizing the fourth polarized signal in the first frequency band and the third polarized signal in the second frequency band. Is selected for each output terminal of the first to fourth output terminals according to a selection signal supplied from the outside, and the band changeover switch for outputting the selected signals from the respective output terminals of the first to fourth output terminals And a low-pass filter for attenuating the first frequency band component in the output signal from the second output terminal. A filter, a trap circuit disposed before or after the low-pass filter, for attenuating a component of the first frequency band in the output signal from the second output terminal, and a first by the low-pass filter and the trap circuit. A synthesizer that synthesizes an output signal from the second output terminal in which the frequency band component is attenuated and a signal based on the output signal from the first output terminal, and the first polarization signal in the second frequency band The second polarization signal in the first frequency band, the third polarization signal in the second frequency band, the fourth polarization signal in the first frequency band, the second combined signal, and the fourth combined signal in the band changeover switch It is generated .

  When the first frequency band component in the output signal from the second output terminal is an unnecessary signal component, it is desirable to remove the unnecessary signal component as much as possible before supplying it to the synthesizer. Since the trap circuit is provided in addition to the low-pass filter, the output signal from the second output terminal can be supplied to the synthesizer after the first frequency band component is sufficiently attenuated. Thereby, in the synthesizer, unnecessary signal components to be superimposed on the signal based on the output signal from the first output terminal are reduced, and as a result, the occurrence of spurious is suppressed.

  Further, for example, in the first satellite broadcast receiving converter, the trap circuit may be composed of a plurality of trap portions having predetermined different frequencies in the second frequency band as attenuation center frequencies. .

  Thereby, an unnecessary signal component can be attenuated over a wide band. As a result, the occurrence of spurious is further suppressed.

  Further, for example, in the second satellite broadcast receiving converter, the trap circuit may be composed of a plurality of trap portions having predetermined different frequencies in the first frequency band as attenuation center frequencies. .

  Thereby, an unnecessary signal component can be attenuated over a wide band. As a result, the occurrence of spurious is further suppressed.

  Specifically, for example, each trap unit is a series resonant circuit including an inductive element and a capacitive element, and the attenuation center frequency is a series resonant frequency.

In order to achieve the above object, a third satellite broadcast receiving converter according to the present invention converts the first polarization signal contained in the broadcast radio wave from the first satellite into the first frequency band and outputs it. A first mixer that converts the second polarization signal contained in the broadcast radio wave from the first satellite into a second frequency band lower than the first frequency band, and a second satellite. A third polarization signal included in the broadcast radio wave from the first satellite is converted into a first frequency band and output; and a fourth polarization signal included in the broadcast radio wave from the second satellite is converted into the second frequency band. A fourth mixer that converts and outputs the first mixer, a first input terminal that receives a signal obtained by combining the output signal of the first mixer and the output signal of the second mixer, and the output signal of the third mixer and the output signal of the fourth mixer And a second input terminal for receiving a combined signal, and a first output A first combined signal having a terminal, a second output terminal, a third output terminal, and a fourth output terminal, and combining the first polarization signal in the first frequency band and the second polarization signal in the second frequency band; A second synthesized signal obtained by synthesizing the second polarization signal in the first frequency band and the first polarization signal in the second frequency band; the third polarization signal in the first frequency band; and the fourth polarization in the second frequency band. One of the third synthesized signal obtained by synthesizing the signal and the fourth synthesized signal obtained by synthesizing the fourth polarized signal in the first frequency band and the third polarized signal in the second frequency band. Is selected for each output terminal of the first to fourth output terminals according to a selection signal supplied from the outside, and the band changeover switch for outputting the selected signals from the respective output terminals of the first to fourth output terminals And a first harmonic for attenuating the second frequency band component in the output signal from the first output terminal. A pass filter, a first low-pass filter for attenuating the first frequency band component in the output signal from the second output terminal, and a second frequency band component in the output signal from the third output terminal A first high-pass filter, a second low-pass filter for attenuating a component of the first frequency band in the output signal from the fourth output terminal, and a first output after the first high-pass filter. A first trap circuit for attenuating a component of the second frequency band in the output signal from the terminal, and a first frequency band in the output signal from the second output terminal, disposed in the front stage or the rear stage of the first low-pass filter The second trap circuit for attenuating the component of the signal and the output signal from the third output terminal are arranged before or after the second high-pass filter. The third trap circuit for attenuating the second frequency band component in the signal and the second or low-pass filter are arranged before or after the second low-pass filter, and attenuate the first frequency band component in the output signal from the fourth output terminal. A fourth trap circuit, an output signal from the first output terminal in which a component of the second frequency band is attenuated by the first high-pass filter and the first trap circuit, a first low-pass filter and a second trap circuit, The second frequency band component is attenuated by the first combiner that synthesizes the output signal from the second output terminal in which the first frequency band component is attenuated by the second high-pass filter and the third trap circuit. An output signal from the third output terminal, and an output signal from the fourth output terminal in which the component of the first frequency band is attenuated by the second low-pass filter and the fourth trap circuit. Comprising a second combiner for forming the first polarization signal of the second frequency band, a second polarization signal of the first frequency band, a third polarization signal of the second frequency band, the first frequency band first The 4-polarized signal, the second combined signal, and the fourth combined signal are generated in the band changeover switch .

  When the second frequency band component in the output signal from the first output terminal is an unnecessary signal component, it is desirable to remove the unnecessary signal component as much as possible before supplying it to the first combiner. Since the first trap circuit is provided in addition to the first high-pass filter, the second frequency band component is sufficiently attenuated and the output signal from the first output terminal is supplied to the first combiner. be able to. As a result, in the first combiner, unnecessary signal components superimposed on the signal based on the output signal from the second output terminal are reduced, and as a result, the occurrence of spurious is suppressed.

  Similarly, since the third trap circuit is provided, in the second synthesizer, unnecessary signal components superimposed on the signal based on the output signal from the fourth output terminal are reduced, and as a result, the occurrence of spurious is suppressed. The

  If the first frequency band component in the output signal from the second output terminal is an unnecessary signal component, it is desirable to remove the unnecessary signal component as much as possible before supplying it to the first combiner. In the above configuration, since the second trap circuit is provided in addition to the first low-pass filter, the output signal from the second output terminal is supplied to the first combiner after sufficiently attenuating the first frequency band component. Can be supplied. Thereby, in the first combiner, unnecessary signal components superimposed on the signal based on the output signal from the first output terminal are reduced, and as a result, the occurrence of spurious is suppressed.

  Similarly, since the fourth trap circuit is provided, unnecessary signal components superimposed on the signal based on the output signal from the third output terminal are reduced in the second synthesizer, and as a result, the occurrence of spurious is suppressed. The

  For example, the first polarization signal and the second polarization signal are a left-hand polarization signal and a right-hand polarization signal, respectively. For example, the first polarization signal and the second polarization signal are a right-handed polarization signal and a left-handed polarization signal, respectively.

  Further, for example, the third polarization signal and the fourth polarization signal are a left-handed polarization signal and a right-handed polarization signal, respectively. Further, for example, the third polarization signal and the fourth polarization signal are a right-handed polarization signal and a left-handed polarization signal, respectively.

  As described above, according to the satellite broadcast receiving converter according to the present invention, unnecessary signal components can be reduced, and as a result, occurrence of spurious can be suppressed.

  Hereinafter, embodiments of a satellite broadcast receiving converter according to the present invention will be described in detail with reference to the drawings. An embodiment in which the present invention is applied to a satellite broadcast low noise converter (LNB) which is a kind of satellite broadcast reception converter will be described.

  FIG. 1 shows a block diagram of the LNB according to the present embodiment. In FIG. 1, the same parts in FIG. That is, in FIG. 1, the parts denoted by the same reference numerals as those in FIG. 2 perform the same operations as those described with reference to FIG.

  In FIG. 1, the antenna probe 30, the line 1, the line 2, the LNA 3, the BPF 4 and 5, the mixers 6 and 7, the local oscillators 8 and 9, the HPF 10, the LPF 11, the IF mixing circuit (synthesizer) 12, The connection relationship between the band changeover switch 14, the HPF 15 and the LPF 16, the connection relationship between the IF mixing circuit (synthesizer) 17, the IF amplifier 18, the capacitor 19, the output port 20 and the control unit 21, the antenna probe 60, the line 31, and the line 32. , LNA 33, BPF 34, 35, mixers 36, 37, local oscillators 8, 9, HPF 40, LPF 41, IF mixing circuit (synthesizer) 42, IF amplifier 43, band changeover switch 44, HPF 45 and LPF 46, IF mixing circuit (Synthesizer) 47, IF amplifier 48, capacitor 49, output port 50, and control unit 2 And connection relation, the connection relation of the band changeover switch 14 and the control unit 21 are the same as those in FIG.

  A DC voltage is supplied to the output port 20 from the tuner (not shown) side. The DC voltage is made constant by a regulator (not shown) and supplied as a power supply voltage to each circuit such as LNA 3 in the LNB.

  It should be noted that in FIG. 1, a trap circuit 31 is provided in the subsequent stage of the HPF 15, a trap circuit 32 is provided in the subsequent stage of the LPF 16, and a trap circuit 61 is provided in the subsequent stage of the HPF 45. And a trap circuit 62 is provided after the LPF 46. This will be described in more detail.

  The output side of the HPF 15 is commonly connected to one end of an inductor L 1 as an inductive element, one end of an inductor L 2 as an inductive element, and one input terminal of an IF mixing circuit (synthesizer) 17. The other end of the inductor L1 is connected to one end of a capacitor C1 as a capacitive element, and a reference potential is applied to the other end of the capacitor C1. The other end of the inductor L2 is connected to one end of a capacitor C2 as a capacitive element, and the reference potential is applied to the other end of the capacitor C2. The trap circuit 31 includes inductors L1 and L2 and capacitors C1 and C2.

  The output side of the LPF 16 is commonly connected to one end of an inductor L 3 as an inductive element, one end of an inductor L 4 as an inductive element, and the other input terminal of the IF mixing circuit (synthesizer) 17. The other end of the inductor L3 is connected to one end of a capacitor C3 as a capacitive element, and the reference potential is applied to the other end of the capacitor C3. The other end of the inductor L4 is connected to one end of a capacitor C4 as a capacitive element, and the reference potential is applied to the other end of the capacitor C4. The trap circuit 32 includes inductors L3 and L4 and capacitors C3 and C4.

  The IF mixing circuit 17 combines (combines) the output signal of the HPF 15 input via the trap circuit 31 and the output signal of the LPF 16 input via the trap circuit 32 and supplies the combined signal to the IF amplifier 18. Will do.

  The output side of the HPF 45 is commonly connected to one end of an inductor L 5 as an inductive element, one end of an inductor L 6 as an inductive element, and one input terminal of an IF mixing circuit (synthesizer) 47. The other end of the inductor L5 is connected to one end of a capacitor C5 as a capacitive element, and the reference potential is applied to the other end of the capacitor C5. The other end of the inductor L6 is connected to one end of a capacitor C6 as a capacitive element, and the reference potential is applied to the other end of the capacitor C6. The trap circuit 61 includes inductors L5 and L6 and capacitors C5 and C6.

  The output side of the LPF 46 is commonly connected to one end of an inductor L 7 as an inductive element, one end of an inductor L 8 as an inductive element, and the other input terminal of the IF mixing circuit (synthesizer) 47. The other end of the inductor L7 is connected to one end of a capacitor C7 as a capacitive element, and the reference potential is applied to the other end of the capacitor C7. The other end of the inductor L8 is connected to one end of a capacitor C8 as a capacitive element, and the reference potential is applied to the other end of the capacitor C8. The trap circuit 62 includes inductors L7 and L8 and capacitors C7 and C8. For example, the other ends of the capacitors C1, C2, C3, C4, C5, C6, C7, and C8 are grounded.

  The IF mixing circuit 47 combines (combines) the output signal of the HPF 45 input via the trap circuit 61 and the output signal of the LPF 46 input via the trap circuit 62, and supplies the combined signal to the IF amplifier 48. Will do.

  The resonance frequency f1 of the series resonance circuit (trap section) composed of the inductor L1 and the capacitor C1 and the resonance frequency f2 of the series resonance circuit (trap section) composed of the inductor L2 and the capacitor C2 are both low frequency side bands (950 MHz to 1450 MHz). The inductances of the inductors L1 and L2 and the capacitances of the capacitors C1 and C2 are set in advance so that the resonance frequency f1 and the resonance frequency f2 are different.

  That is, the trap circuit 31 attenuates an unnecessary signal component in the signal output from the first output terminal 14a of the band changeover switch 14, that is, a frequency component in the low frequency side band. The unnecessary signal component is also attenuated by the HPF 15, but the unnecessary signal component can be further attenuated by the presence of the trap circuit 31. As a result, the occurrence of spurious is suppressed.

  The trap circuit 31 includes two series resonance circuits (trap portions) having predetermined different frequencies in the low frequency side band (950 MHz to 1450 MHz) as attenuation center frequencies. The component can be attenuated. As a result, the occurrence of spurious is further suppressed.

  Similarly, the resonance frequency f5 of the series resonance circuit (trap section) composed of the inductor L5 and the capacitor C5 and the resonance frequency f6 of the series resonance circuit (trap section) composed of the inductor L6 and the capacitor C6 are both low frequency side bands (950 MHz to The inductances of the inductors L5 and L6 and the capacitances of the capacitors C5 and C6 are set in advance so that the resonance frequency f5 and the resonance frequency f6 are different. As a result, the same effect (suppression of spurious generation due to further attenuation of unnecessary signal components and attenuation over a wide band) can be obtained.

  The inductance of the inductor L1 may be set so that the resonance frequencies f1 and f2 of the two series resonance circuits (trap units) in the trap circuit 31 are equal. Similarly, the inductance of the inductor L5 may be set so that the resonance frequencies f5 and f6 of the two series resonance circuits (trap units) in the trap circuit 61 are equal. However, in order to obtain an attenuation effect over a wide band, the inductances and the like of the inductors L1 and L5 are set so that the resonance frequencies f1 and f2 are different frequencies and the resonance frequencies f5 and f6 are different frequencies. It is desirable. Further, the resonance frequencies f1, f2, f5 and f6 may all be the same.

  In addition, although an example in which each of the trap circuits 31 and 61 includes two series resonance circuits (trap units) is shown in FIG. 1, the number of series resonance circuits is not limited to “2”. That is, any integer value of 1 or more can be adopted as the number of series resonant circuits.

  Further, although an example in which the trap circuit 31 is provided in the subsequent stage of the HPF 15 is shown in FIG. 1, the trap circuit 31 may be provided in the subsequent stage of the band changeover switch 14 and in front of the HPF 15. Similarly, an example in which the trap circuit 61 is provided in the subsequent stage of the HPF 45 is shown in FIG. 1, but the trap circuit 61 may be provided in the subsequent stage of the band changeover switch 14 and in the previous stage of the HPF 45.

  Further, the resonance frequency f3 of the series resonance circuit (trap section) composed of the inductor L3 and the capacitor C3 and the resonance frequency f4 of the series resonance circuit (trap section) composed of the inductor L4 and the capacitor C4 are both high frequency side bands (1650 MHz to 2150 MHz). The inductances of the inductors L3 and L4 and the capacitances of the capacitors C3 and C4 are set in advance so that the resonance frequency f3 and the resonance frequency f4 are different.

  That is, the trap circuit 32 attenuates unnecessary signal components in the signal output from the second output terminal 14b of the band changeover switch 14, that is, frequency components in the high frequency side band. The unnecessary signal component is attenuated also by the LPF 16, but the unnecessary signal component can be further attenuated by the presence of the trap circuit 32. As a result, the occurrence of spurious is suppressed.

  The trap circuit 32 is composed of two series resonance circuits (trap portions) having predetermined different frequencies in the high frequency side band (1650 MHz to 2150 MHz) as attenuation center frequencies. Therefore, unnecessary signal components over a wide band. Can be attenuated. As a result, the occurrence of spurious is further suppressed.

  Similarly, the resonance frequency f7 of the series resonance circuit (trap section) composed of the inductor L7 and the capacitor C7 and the resonance frequency f8 of the series resonance circuit (trap section) composed of the inductor L8 and the capacitor C8 are both high frequency sidebands (1650 MHz to 2150 MHz). The inductances of the inductors L7 and L8 and the capacitances of the capacitors C7 and C8 are set in advance so that the resonance frequency f7 and the resonance frequency f8 are different. As a result, the same effect (suppression of spurious generation due to further attenuation of unnecessary signal components and attenuation over a wide band) can be obtained.

  Note that the inductance of the inductor L3 and the like may be set so that the resonance frequencies f3 and f4 of the two series resonance circuits (trap portions) in the trap circuit 32 are equal. Similarly, the inductance of the inductor L7 may be set so that the resonance frequencies f7 and f8 of the two series resonance circuits (trap units) in the trap circuit 62 are equal. However, in order to obtain an attenuation effect over a wide band, the inductances of the inductors L3 and L7 are set so that the resonance frequencies f3 and f4 are different from each other and the resonance frequencies f7 and f8 are different from each other. It is desirable. The resonance frequencies f3, f4, f7 and f8 may all be the same.

  In addition, although an example in which each of the trap circuits 32 and 62 includes two series resonance circuits (trap units) is shown in FIG. 1, the number of series resonance circuits is not limited to “2”. That is, any integer value of 1 or more can be adopted as the number of series resonant circuits.

  Further, although an example in which the trap circuit 32 is provided in the subsequent stage of the LPF 16 is shown in FIG. 1, the trap circuit 32 may be provided in the subsequent stage of the band changeover switch 14 and in front of the LPF 16. Similarly, an example in which the trap circuit 62 is provided in the subsequent stage of the LPF 46 is shown in FIG. 1, but the trap circuit 62 may be provided in the subsequent stage of the band changeover switch 14 and in front of the LPF 46.

(Deformation)
Although an embodiment of the present invention has been described by taking a 2-satellite reception and 2-output type LNB as an example, the present invention describes an n-satellite reception and m-output type (n is an arbitrary integer of 2 or more, The present invention can be widely applied to satellite broadcast receiving converters in which m is an arbitrary integer of 2 or more.

  In FIG. 1, the antenna provided with the antenna probe 30 and the antenna provided with the antenna probe 60 are described as separate, but may be separate or integrated. It does not matter (that is, the antenna probe 30 and the antenna probe 60 may be provided in one antenna).

  According to the satellite broadcast receiving converter of the present invention, unnecessary signal components can be reduced, and as a result, occurrence of spurious can be suppressed.

It is an electrical block diagram of LNB which concerns on embodiment of this invention. It is an electrical block diagram of the conventional LNB. It is a figure for demonstrating operation | movement of the band change switch periphery of FIG.1 and FIG.2. It is a figure for demonstrating the output signal of the band change switch of FIG.1 and FIG.2.

Explanation of symbols

1, 2, 31, 32 Line 3, 33 LNA
4, 5, 34, 35 BPF
6, 7, 36, 37 Mixer 8, 9 Local oscillator 10, 40 HPF
11, 41 LPF
12, 17, 42, 47 IF mixing circuit (synthesizer)
13, 18, 43, 48 IF amplifier 14 Band selection switch 14a First output terminal 14b Second output terminal 14c Third output terminal 14d Fourth output terminal 15, 45 HPF
16, 46 LPF
19, 49 Capacitor 20, 50 Output port 30, 60 Antenna probe 31, 32, 61, 62 Trap circuit L1, L2, L3, L4, L5, L6, L7, L8 Inductors C1, C2, C3, C4, C5, C6 , C7, C8 capacitors

Claims (6)

A first mixer that converts a first polarization signal included in a broadcast radio wave from the first satellite into a first frequency band and outputs the first polarization signal;
A second mixer that converts the second polarization signal included in the broadcast radio wave from the first satellite into a second frequency band on the lower frequency side than the first frequency band and outputs the second polarization signal;
A third mixer for converting the third polarization signal included in the broadcast radio wave from the second satellite to the first frequency band and outputting the first polarization band;
A fourth mixer for converting the fourth polarization signal contained in the broadcast radio wave from the second satellite to the second frequency band and outputting the second polarization signal;
A first input terminal that receives a signal obtained by combining the output signal of the first mixer and an output signal of the second mixer, and a second input terminal that receives a signal obtained by combining the output signal of the third mixer and the output signal of the fourth mixer And having a first output terminal, a second output terminal, a third output terminal and a fourth output terminal,
A first synthesized signal obtained by synthesizing the first polarization signal in the first frequency band and the second polarization signal in the second frequency band;
A second synthesized signal obtained by synthesizing the second polarization signal in the first frequency band and the first polarization signal in the second frequency band;
A third synthesized signal obtained by synthesizing the third polarization signal in the first frequency band and the fourth polarization signal in the second frequency band, and a third polarization of the fourth polarization signal in the first frequency band and the second frequency band. One of the fourth synthesized signals synthesized with the wave signal is selected for each output terminal of the first to fourth output terminals according to the selection signal supplied from the outside, and these are selected. A band changeover switch for outputting the received signal from each output terminal of the first to fourth output terminals;
A high-pass filter for attenuating the component of the second frequency band in the output signal from the first output terminal;
A trap circuit disposed before or after the high-pass filter for attenuating a component of the second frequency band in the output signal from the first output terminal;
A synthesizer that synthesizes an output signal from the first output terminal in which a component of the second frequency band is attenuated by the high-pass filter and the trap circuit and a signal based on the output signal from the second output terminal; ,
The first polarization signal in the second frequency band, the second polarization signal in the first frequency band, the third polarization signal in the second frequency band, the fourth polarization signal in the first frequency band, the second combined signal, and the second A satellite broadcast receiving converter , wherein the four composite signals are generated in the band changeover switch . A first mixer that converts a first polarization signal included in a broadcast radio wave from the first satellite into a first frequency band and outputs the first polarization signal;
A second mixer that converts the second polarization signal included in the broadcast radio wave from the first satellite into a second frequency band on the lower frequency side than the first frequency band and outputs the second polarization signal;
A third mixer for converting the third polarization signal included in the broadcast radio wave from the second satellite to the first frequency band and outputting the first polarization band;
A fourth mixer for converting the fourth polarization signal contained in the broadcast radio wave from the second satellite to the second frequency band and outputting the second polarization signal;
A first input terminal that receives a signal obtained by combining the output signal of the first mixer and an output signal of the second mixer, and a second input terminal that receives a signal obtained by combining the output signal of the third mixer and the output signal of the fourth mixer And having a first output terminal, a second output terminal, a third output terminal and a fourth output terminal,
A first synthesized signal obtained by synthesizing the first polarization signal in the first frequency band and the second polarization signal in the second frequency band;
A second synthesized signal obtained by synthesizing the second polarization signal in the first frequency band and the first polarization signal in the second frequency band;
A third synthesized signal obtained by synthesizing the third polarization signal in the first frequency band and the fourth polarization signal in the second frequency band, and a third polarization of the fourth polarization signal in the first frequency band and the second frequency band. One of the fourth synthesized signals synthesized with the wave signal is selected for each output terminal of the first to fourth output terminals according to the selection signal supplied from the outside, and these are selected. A band changeover switch for outputting the received signal from each output terminal of the first to fourth output terminals;
A low-pass filter for attenuating a component of the first frequency band in the output signal from the second output terminal;
A trap circuit disposed before or after the low-pass filter, for attenuating a component of the first frequency band in the output signal from the second output terminal;
A synthesizer that synthesizes an output signal from the second output terminal, the first frequency band component of which is attenuated by the low-pass filter and the trap circuit, and a signal based on the output signal from the first output terminal; ,
The first polarization signal in the second frequency band, the second polarization signal in the first frequency band, the third polarization signal in the second frequency band, the fourth polarization signal in the first frequency band, the second combined signal, and the second A satellite broadcast receiving converter , wherein the four composite signals are generated in the band changeover switch . 2. The satellite broadcast receiving converter according to claim 1, wherein the trap circuit includes a plurality of trap units having predetermined different frequencies in the second frequency band as attenuation center frequencies. 3. The satellite broadcast receiving converter according to claim 2, wherein the trap circuit includes a plurality of trap units having predetermined different frequencies in the first frequency band as attenuation center frequencies. 4. Each trap part is a series resonant circuit composed of an inductive element and a capacitive element,
5. The satellite broadcast receiving converter according to claim 3, wherein the attenuation center frequency is a series resonance frequency. A first mixer that converts a first polarization signal included in a broadcast radio wave from the first satellite into a first frequency band and outputs the first polarization signal;
A second mixer that converts the second polarization signal included in the broadcast radio wave from the first satellite into a second frequency band on the lower frequency side than the first frequency band and outputs the second polarization signal;
A third mixer for converting the third polarization signal included in the broadcast radio wave from the second satellite to the first frequency band and outputting the first polarization band;
A fourth mixer for converting the fourth polarization signal contained in the broadcast radio wave from the second satellite to the second frequency band and outputting the second polarization signal;
A first input terminal that receives a signal obtained by combining the output signal of the first mixer and an output signal of the second mixer, and a second input terminal that receives a signal obtained by combining the output signal of the third mixer and the output signal of the fourth mixer And having a first output terminal, a second output terminal, a third output terminal and a fourth output terminal,
A first synthesized signal obtained by synthesizing the first polarization signal in the first frequency band and the second polarization signal in the second frequency band;
A second synthesized signal obtained by synthesizing the second polarization signal in the first frequency band and the first polarization signal in the second frequency band;
A third synthesized signal obtained by synthesizing the third polarization signal in the first frequency band and the fourth polarization signal in the second frequency band, and a third polarization of the fourth polarization signal in the first frequency band and the second frequency band. One of the fourth synthesized signals synthesized with the wave signal is selected for each output terminal of the first to fourth output terminals according to the selection signal supplied from the outside, and these are selected. A band changeover switch for outputting the received signal from each output terminal of the first to fourth output terminals;
A first high-pass filter for attenuating a component of the second frequency band in the output signal from the first output terminal;
A first low-pass filter for attenuating a component of the first frequency band in the output signal from the second output terminal;
A second high-pass filter for attenuating the second frequency band component in the output signal from the third output terminal;
A second low-pass filter for attenuating a component of the first frequency band in the output signal from the fourth output terminal;
A first trap circuit disposed before or after the first high-pass filter for attenuating a component of the second frequency band in the output signal from the first output terminal;
A second trap circuit disposed before or after the first low-pass filter, for attenuating a component of the first frequency band in the output signal from the second output terminal;
A third trap circuit disposed before or after the second high-pass filter for attenuating a component of the second frequency band in the output signal from the third output terminal;
A fourth trap circuit disposed before or after the second low-pass filter for attenuating a component of the first frequency band in the output signal from the fourth output terminal;
The output signal from the first output terminal in which the component of the second frequency band is attenuated by the first high-pass filter and the first trap circuit, and the component of the first frequency band is attenuated by the first low-pass filter and the second trap circuit. A first combiner that combines the output signal from the second output terminal,
The output signal from the third output terminal in which the second frequency band component is attenuated by the second high-pass filter and the third trap circuit, and the first frequency band component is attenuated by the second low-pass filter and the fourth trap circuit. A second synthesizer for synthesizing the output signal from the fourth output terminal ,
The first polarization signal in the second frequency band, the second polarization signal in the first frequency band, the third polarization signal in the second frequency band, the fourth polarization signal in the first frequency band, the second combined signal, and the second A satellite broadcast receiving converter , wherein the four composite signals are generated in the band changeover switch .

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