CN210111951U - Output circuit for down converter - Google Patents
Output circuit for down converter Download PDFInfo
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- CN210111951U CN210111951U CN201920804631.7U CN201920804631U CN210111951U CN 210111951 U CN210111951 U CN 210111951U CN 201920804631 U CN201920804631 U CN 201920804631U CN 210111951 U CN210111951 U CN 210111951U
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Abstract
The utility model discloses an output circuit for a down converter, which comprises an oscillator and a filter, wherein the output end of the oscillator is connected with the input end of the filter; the oscillator is used for generating a mixed signal, the oscillator comprises an arithmetic unit U1 and a feedback loop, the feedback loop can generate a local oscillation signal and transmit the local oscillation signal to the arithmetic unit U1 to be mixed with an input signal, the filter is used for filtering a miscellaneous signal in the mixed signal to output a required intermediate frequency signal, the filter comprises a high-pass filter and a low-pass filter, and a matching element is further arranged between the oscillator and the input end of the down converter; the feedback loop includes transformers T1, T2, resistors R2, R4, and a resonant circuit. The utility model discloses a combination of oscillator and wave filter has guaranteed the stable temperature of this down converter during operation when reducing circuit structure, and has improved the output rate, reduces the signal loss rate.
Description
Technical Field
The utility model relates to a down converter output circuit technical field especially relates to an output circuit for down converter.
Background
In a receiver, if the intermediate frequency signal obtained after mixing is lower than the original signal, the mixing is called down-conversion. The purpose of down-conversion is to reduce the carrier frequency of the signal or to directly remove the carrier frequency to obtain a baseband signal. The down-conversion mode has simple circuit and low cost, so the down-conversion mode is widely applied to civil equipment and military equipment with low performance requirement. The general down converter mixes the received signal with the local oscillator signal in the body and performs low-pass filtering. Therefore, the oscillating circuit, the mixer and the filter are usually included in the down converter, but the conventional mixer generates thermal noise when in operation, so that when the whole down converter is in operation, the internal temperature rises and simultaneously great noise is generated, and the mixer enlarges the circuit volume inside the whole down converter, thereby increasing the cost.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a: to overcome the above-mentioned drawbacks, an output circuit for a down converter is proposed to reduce noise while stabilizing the operating temperature of the down converter.
In order to achieve the above purpose, the technical scheme of the utility model is that: an output circuit for a down converter comprises an oscillator and a filter, wherein the output end of the oscillator is connected with the input end of the filter; the oscillator is used for generating a mixed signal and comprises an arithmetic unit U1 and a feedback loop, the feedback loop can generate a local oscillation signal and transmit the local oscillation signal to the arithmetic unit U1 to be mixed with an external input signal, the filter is used for filtering a miscellaneous signal in the mixed signal to output a required intermediate frequency signal, the filter comprises a high-pass filter and a low-pass filter, and a matching element is further arranged between the oscillator and the input end of the down converter.
Further, the feedback loop includes transformers T1, T2, resistors R2, R4, and a resonant circuit.
Furthermore, the resonant circuit comprises a resistor R3, an inductor L1 and a capacitor C1, one end of the resistor R2 is connected to the input end of the operator U1, the input end of the operator U1 serves as the input end of the oscillator, the other end of the resistor R2 is connected to one end of the secondary side of the transformer T1, one end of the primary side of the transformer T1 is connected to one end of the resistor R3, the inductor L1 and the capacitor C1 and then connected to one end of the secondary side of the transformer T2, and the other end of the primary side of the transformer T1 is connected to the other end of the resistor R3, the inductor L1 and the capacitor C1 and then connected to the other end of the secondary side of the transformer T2; the other end of the secondary side of the transformer T1 and the other end of the primary side of the transformer T2 are both grounded, one end of the primary side of the transformer T2 is connected to one end of a resistor R4, the other end of the resistor R4 is connected to the output end of an arithmetic unit U1, and the output end of the arithmetic unit U1 serving as the output end of the oscillator is connected with a filter.
Furthermore, the filter comprises inductors L2-L8 and capacitors C2-C5, wherein the capacitors C2-C3 and the inductors L2-L3 form a high-pass filter, and the inductors L7-L8 and the capacitors C4-C5 form a low-pass filter; one end of the inductor L4 is used as the input end of the filter and is connected with the output end of the oscillator, one end of the inductor L4 is also connected with one end of the capacitor C2, the other end of the capacitor C2 is connected with one end of the capacitor C3 and one end of the inductor L2, the other end of the capacitor C3 is connected with one end of the inductor L3, the other ends of the inductors L2 and L3 are grounded; the other end of the inductor L4 is connected to one end of inductors L5 and L7, the other end of the inductor L5 is connected to one end of inductors L6 and L8, the other end of the inductor L7 is connected to one end of a capacitor C4, the other end of the inductor L8 is connected to one end of a capacitor C5, the other ends of the capacitors C4 and C5 are grounded, and the other end of the inductor L6 is used as the output end of the filter.
Further, the matching element is a resistor R1.
Since the proposal is adopted, the beneficial effects of the utility model reside in that: the utility model provides a prior art not enough, the utility model provides a down converter is with output circuit, its benefit is:
(1) the utility model discloses a combination of oscillator and wave filter has guaranteed the stable temperature of this down converter during operation when reducing circuit structure, and has improved the output rate, reduces the signal loss rate.
(2) The utility model discloses an oscillator adopts feedback loop's form, and feedback loop simple structure can obtain local oscillator signal fast in the time of reduce cost to mix local oscillator signal and radio frequency signal, in order to obtain the intermediate frequency signal that needs.
(3) The utility model discloses a high pass filter and low pass filter that the wave filter set up can effectually filter the miscellaneous signal of high frequency and low frequency simultaneously, have reduced the noise of this down converter work.
Drawings
Fig. 1 is a schematic circuit diagram of the output circuit of the present invention.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Examples
As shown in fig. 1, a general down converter mixes a received signal with a local oscillation signal in a main body and performs low-pass filtering in an output circuit for a down converter. Therefore, the oscillating circuit, the mixer and the filter are usually included in the down converter, but the conventional mixer generates thermal noise when in operation, so that when the whole down converter is in operation, the internal temperature rises and simultaneously great noise is generated, and the mixer enlarges the circuit volume inside the whole down converter, thereby increasing the cost. Therefore, the utility model discloses new design has been made in order to reduce the noise when down converter operation in the cost-effective time to the internal circuit of down converter.
The output circuit comprises an oscillator and a filter, the oscillator is used for generating mixed signals, external radio frequency signals are input into the down converter and mixed with local oscillation signals generated inside the oscillator, and then the filter filters the residual signals to output required intermediate frequency signals.
Specifically, the oscillator comprises an arithmetic unit U1, transformers T1, T2, resistors R2-R4, an inductor L1 and a capacitor C1, wherein the resistance values of the resistors R2 and R4 are 76 Ω, the resistance value of the resistor R3 is 33 Ω, the value of the inductor L1 is 52 μ H, and the capacitance value of the capacitor C1 is 33 μ F; the type of the arithmetic unit U1 adopts A08 series, and the type of the transformer adopts GDYD series. The oscillator comprises a transformer T1, a transformer T2, resistors R2-R4, an inductor L1 and a capacitor C1, wherein the transformer T1, the resistor T2, the resistors R2-R4 and the capacitor C1 are feedback loops in the oscillator. The other end of the resistor R2 is connected with one end of the secondary side of the transformer T1, one end of the primary side of the transformer T1 is connected with one end of the resistor R3, the inductor L1 and the capacitor C1 and then connected with one end of the secondary side of the transformer T2, and the other end of the primary side of the transformer T1 is connected with the other end of the resistor R3, the inductor L1 and the capacitor C1 and then connected with the other end of the secondary side of the transformer T2; the other end of the secondary side of the transformer T1 and the other end of the primary side of the transformer T2 are both grounded, one end of the primary side of the transformer T2 is connected to one end of a resistor R4, the other end of the resistor R4 is connected to the output end of an arithmetic unit U1, and the output end of the arithmetic unit U1 serving as the output end of the oscillator is connected with a filter. The transformers T1 and T2 can amplify and reduce signals, the transformer T2 is used for amplifying a source signal before oscillation starting, the transformer T1 is used for restoring an original frequency of a local oscillation signal after oscillation starting so as to be conveniently input into the arithmetic unit U1, and the resonance circuit formed by the resistor R3, the inductor L1 and the capacitor C1 realizes oscillation of the circuit, so that a required local oscillation signal is obtained. The source signal is input into the feedback loop from the output end of the arithmetic unit U1, and the local oscillation signal is output to the input end of the arithmetic unit U1 through one end of the resistor R2 so as to be mixed with the input radio frequency signal. Meanwhile, because the arithmetic unit U1 is composed of a single-stage composite transistor pair with series-parallel resistive feedback, when the circuit works, the working static point of the transistor is unstable, so that the working temperature of the whole oscillator is increased, and the working static point of the transistor in the arithmetic unit U1 can be stabilized through the symmetrically arranged feedback loops, so that better temperature stability is obtained, and the thermal noise in the circuit is further reduced.
In this embodiment, the matching element is a resistor R1 with a resistance of 50 Ω, the other end of the resistor R1 is connected with one end of the resistor R2, and one end of the resistor R1 is used as the input end of the down converter and is connected with an external radio frequency signal. After the external radio frequency signal is input into the down converter, the external radio frequency signal is transmitted into the oscillator through the resistor R1. Because the resistor R1 is used as a matching element, partial signal reflection of the signal transmitted into the down converter can be avoided, and the output power is improved. After the signal passing through the resistor R1 is transmitted to the oscillator for signal mixing, the output signal can be transmitted to the filter for filtering the miscellaneous signals, and finally the required intermediate frequency signal is output.
The input end of the filter is connected with the output end of the oscillator and used for filtering the mixed signal output by the oscillator to obtain an intermediate frequency signal required to be output. Specifically, the filter comprises inductors L2-L8 and capacitors C2-C5, wherein the values of the inductors L2-L3 are 110 muH, the values of the inductors L7-L8 are 51 muH, the value of the inductor L4 is 100 muH, the value of the inductor L5 is 78 muH, the value of the inductor L6 is 150 muH, the capacitance values of the capacitors C2-C3 are 78 muF, and the capacitance values of the capacitors C4-C5 are 56 muF. One end of the inductor L4 is used as the input end of the filter and connected with the output end of the oscillator, one end of the inductor L4 is further connected to one end of the capacitor C2, the other end of the capacitor C2 is connected to one ends of the capacitor C3 and the inductor L2, the other end of the capacitor C3 is connected to one end of the inductor L3, and the other ends of the inductors L2 and L3 are both grounded. The other end of the inductor L4 is connected to one ends of inductors L5 and L7, the other end of the inductor L5 is connected to one ends of inductors L6 and L8, the other end of the inductor L7 is connected to one end of a capacitor C4, the other end of the inductor L8 is connected to one end of a capacitor C5, the other ends of the capacitors C4 and C5 are both grounded, and the other end of the inductor L6 serves as an output end of the filter. The capacitors C2-C3 and the inductors L2-L3 form a high-pass filter, the inductors L7-L8 and the capacitors C4-C5 form a low-pass filter, so that high-frequency and partial low-frequency signals and other miscellaneous signals input into the filter can be filtered conveniently, noise during operation of the down converter is effectively reduced, and finally required intermediate-frequency signals are output through the inductors L6.
Parts not described in the above modes can be realized by adopting or referring to the prior art.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing embodiments, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. An output circuit for a down converter, characterized in that: the output end of the oscillator is connected with the input end of the filter; the oscillator is used for generating a mixed signal and comprises an arithmetic unit U1 and a feedback loop, the feedback loop can generate a local oscillation signal and transmit the local oscillation signal to the arithmetic unit U1 to be mixed with an external input signal, the filter is used for filtering a miscellaneous signal in the mixed signal to output a required intermediate frequency signal, the filter comprises a high-pass filter and a low-pass filter, and a matching element is further arranged between the oscillator and the input end of the down converter.
2. The output circuit for a down converter according to claim 1, wherein: the feedback loop includes transformers T1, T2, resistors R2, R4, and a resonant circuit.
3. The output circuit for a down converter according to claim 2, wherein: the resonant circuit comprises a resistor R3, an inductor L1 and a capacitor C1, one end of the resistor R2 is connected to the input end of an operator U1, the input end of the operator U1 serves as the input end of the oscillator, the other end of the resistor R2 is connected with one end of the secondary side of a transformer T1, one end of the primary side of the transformer T1 is connected with one end of a resistor R3, an inductor L1 and a capacitor C1 and then connected with one end of the secondary side of the transformer T2, the other end of the primary side of the transformer T1 is connected with the other end of the secondary side of the transformer T2 and then connected with the other end of the resistor R3, the inductor L; the other end of the secondary side of the transformer T1 and the other end of the primary side of the transformer T2 are both grounded, one end of the primary side of the transformer T2 is connected to one end of a resistor R4, the other end of the resistor R4 is connected to the output end of an arithmetic unit U1, and the output end of the arithmetic unit U1 serving as the output end of the oscillator is connected with a filter.
4. The output circuit for a down converter according to claim 1, wherein: the filter comprises inductors L2-L8 and capacitors C2-C5, wherein the capacitors C2-C3 and the inductors L2-L3 form a high-pass filter, and the inductors L7-L8 and the capacitors C4-C5 form a low-pass filter; one end of the inductor L4 is used as the input end of the filter and is connected with the output end of the oscillator, one end of the inductor L4 is also connected with one end of the capacitor C2, the other end of the capacitor C2 is connected with one end of the capacitor C3 and one end of the inductor L2, the other end of the capacitor C3 is connected with one end of the inductor L3, the other ends of the inductors L2 and L3 are grounded; the other end of the inductor L4 is connected to one end of inductors L5 and L7, the other end of the inductor L5 is connected to one end of inductors L6 and L8, the other end of the inductor L7 is connected to one end of a capacitor C4, the other end of the inductor L8 is connected to one end of a capacitor C5, the other ends of the capacitors C4 and C5 are grounded, and the other end of the inductor L6 is used as the output end of the filter.
5. The output circuit for a down converter according to claim 1, wherein: the matching element is a resistor R1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920804631.7U CN210111951U (en) | 2019-05-31 | 2019-05-31 | Output circuit for down converter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920804631.7U CN210111951U (en) | 2019-05-31 | 2019-05-31 | Output circuit for down converter |
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| CN210111951U true CN210111951U (en) | 2020-02-21 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115189771A (en) * | 2022-07-08 | 2022-10-14 | 河南信烽通讯科技有限公司 | Optical modem capable of reducing signal loss |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115189771A (en) * | 2022-07-08 | 2022-10-14 | 河南信烽通讯科技有限公司 | Optical modem capable of reducing signal loss |
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