TWI578791B - A signal processing device - Google Patents

Description

Signal processing device

The present invention relates to a signal processing apparatus, and more particularly to a signal processing apparatus that can process mixed television signals and optical television signals.

The program operator or the broadcaster transmits the television signal to the user terminal by using the head end device, and the user terminal can use the television set or the set-top box to perform various processing on the received television signal, and then present the television program or the video and audio multimedia. The transmission form of television signals includes wireless broadcasting and wired transmission. In the case of wireless broadcasting, the form includes satellite transmission and terrestrial wireless transmission; the two wireless transmission systems use antennas to receive television signals, and then transmit them to a set-top box or receiver through a coaxial cable, and after processing , showing TV shows. The application mode of wired transmission can be roughly divided into three types: broadband network, optical fiber and coaxial cable; these three kinds of wired transmissions use television sets or receivers to receive television signals transmitted by broadband networks, optical fibers or coaxial cables, and After being processed, a television program is presented.

However, different types of transmission methods require different types of set-top boxes or signal receivers. Therefore, if the user needs to watch TV programs transmitted by different transmission methods (such as optical fiber transmission and coaxial cable transmission, optical fiber transmission and satellite transmission, or optical fiber transmission and terrestrial wireless transmission), the corresponding set-top box or signal must be used separately. The receiver can receive the desired TV signal. Taking fiber transmission and coaxial cable transmission as an example, since the coaxial cable and the optical fiber cannot be installed on the same set-top box or signal receiver, the user must use two different set-top boxes or signal receivers to watch the coaxial separately. The TV programs transmitted by cables and optical fibers cause great inconvenience and trouble to the user terminal. In addition, for the user side, the use of two different set-top boxes or signal receivers is bound to take up a lot of space and incur additional costs, so volume and cost are also points to be improved.

The main purpose of the present invention is to provide a signal processing device for integrating a low noise amplifier, a transimpedance amplifier, a multiplexer or matrix switch, and a down conversion module into a device (for example, a single semiconductor chip). ), allowing users to watch TV programs transmitted by cables and optical fibers separately.

Another object of the present invention is to provide a signal processing device that integrates a low noise amplifier, a transimpedance amplifier, a multiplexer or matrix switch, and a down conversion module onto a single semiconductor wafer. It can modularly design these circuits to avoid poor matching, which makes the circuit design difficult and cost-effective. In addition, integrating these circuits on a single semiconductor wafer can reduce production costs and reduce the size of the device.

To achieve the above object, the present invention provides a signal processing apparatus which can include a low noise amplifier, a transimpedance amplifier, a multiplexer or matrix switch, and a down conversion module. The multiplexer or matrix switch includes a first switch, a second switch, a third switch, and a fourth switch. An input of the first switch is related to an output of the low noise amplifier, and the first switch can exhibit a first conductive state or a first closed state (ie, the first conductive state and the first closed state), An on state may cause an output of the first switch to be associated with the input of the first switch, and the first off state may cause an electrical disconnection between the output of the first switch and the input of the first switch. An input of the second switch is related to the output of the low noise amplifier, and the second switch can exhibit a second conductive state or a second closed state (ie, the second conductive state and the second closed state), The two-on state may cause an output of the second switch to be associated with the input of the second switch, and the second off state may be in an electrically disconnected state between the output of the second switch and the input of the second switch. An input of the third switch is related to an output of the transimpedance amplifier, and the third switch can exhibit a third conductive state or a third closed state (ie, a third conductive state and a third closed state), and a third The conduction state may cause an output of the third switch to be related to the input of the third switch, and the third closed state may electrically disconnect the output of the third switch from the input of the third switch. An input of the fourth switch is related to the output of the transimpedance amplifier, and the fourth switch can assume a fourth conductive state or a fourth closed state (ie, the fourth conductive state and the fourth closed state are selected), and the fourth The on state may cause an output of the fourth switch to be related to the input of the fourth switch, and the fourth off state may electrically disconnect the output of the fourth switch from the input of the fourth switch. The down conversion module includes a first down converter and a second down converter. The first down converter includes a first mixer, a first frequency synthesizer, a first in-phase quadrature (I/Q) generator, a first channel selection filter, and a first variable gain. Amplifier. a first input of the first mixer is related to the output of the second switch or the output of the fourth switch, and a second input of the first mixer is related to a frequency output by one of the first frequency synthesizers, A mixer is adapted to mix the first input of the first mixer with the second input of the first mixer to produce an output. The second down converter includes a second mixer, a second frequency synthesizer, a second in-phase quadrature (I/Q) generator, a second channel selection filter, and a second variable gain amplifier. . a first input of the second mixer is related to the output of the first switch or the output of the third switch, and a second input of the second mixer is related to a frequency output by one of the second frequency synthesizers, The second mixer is adapted to mix the first input of the second mixer with the second input of the second mixer to produce an output. Low noise amplifiers, transimpedance amplifiers, down conversion modules, and multiplexers or matrix switches can be integrated circuits on a single semiconductor wafer.

These and other components, steps, features, advantages and advantages of the present invention will become apparent from the description of the appended claims.

The drawings disclose illustrative embodiments of the invention. It does not describe all of the embodiments. Other embodiments may be used in addition or instead. In order to save space or more effectively explain, obvious or unnecessary details may be omitted. Instead, some embodiments may be implemented without revealing all the details. When the same number or label appears in a different figure, it refers to the same or similar components or steps. The invention will be more fully understood from the following description, taken in conjunction with the accompanying drawings.

Referring to FIG. 1, the signal processing device 1 of the present invention can receive a first signal transmitted through a cable (for example, a coaxial cable) and/or receive a second signal output from a light receiver 2. The first signal may be an analog or digital form of a hybrid TV signal; the mixed television signal may be a signal received from an antenna. The second signal originates from a signal transmitted through a fiber, such as an analog or digital form of an optical TV signal. The signal processing device 1 can be disposed on a television set, a set-top box (STB), a television signal receiver or a mobile receiving system.

The signal processing device 1 includes a low noise amplifier (LNA) 4, a transimpedence amplifier (TIA) 6, a multiplexer (mux) or a matrix switch 8 and a down converter. The conversion module 10, wherein the multiplexer or matrix switch 8 is located at the downstream end of the signal of the low noise amplifier 4 and the transimpedance amplifier 6, and the down conversion module 10 is located at the downstream end of the signal of the multiplexer or matrix switch 8. The low noise amplifier 4, the transimpedance amplifier 6, the multiplexer or matrix switch 8 and the down conversion module 10 can be integrated circuits on a single semiconductor wafer. Although the present invention uses a low noise amplifier as an example; other amplifiers may be used as an alternative to the low noise amplifier, in addition to the low noise amplifier, if necessary.

The low noise amplifier 4 is configured to receive an input (for example, a single-ended input or a differential input), wherein the input is related to the first signal transmitted by the cable, for example, the input is equal to the first signal; and the first signal includes, for example, A digital signal or a analog signal. The low noise amplifier 4 can be a single-ended input single-ended output amplifier, a single-ended input differential output amplifier, a differential input single-ended output amplifier, or a differential input differential output amplifier. An input terminal 4a of the low noise amplifier 4 can be coupled to the cable, so that the low noise amplifier 4 can receive and amplify the first signal, and then output the amplified first signal from the output terminal 4b (hereinafter referred to as "signal S1" ") to a first input 8a of the multiplexer or matrix switch 8. The output mode of the low noise amplifier 4 can be a single-ended output or a differential output. The transimpedance amplifier 6 is configured to receive an input (eg, a single-ended input or a differential input), wherein the input is related to a second signal generated by the optical receiver 2, for example, the input is equal to the second signal; and the second signal is, for example, Includes a digital signal or a analog signal. When the input of the transimpedance amplifier 6 is a differential input, the sensitivity can be increased. The transimpedance amplifier 6 can be a single-ended input single-ended output amplifier, a single-ended input differential output amplifier, a differential input single-ended output amplifier, or a differential input differential output amplifier. An input terminal 6a of the transimpedance amplifier 6 can be coupled to an output end of the optical receiver 2, so that the transimpedance amplifier 6 can receive the second signal output by the optical receiver 2, and convert the second signal into a voltage difference. A signal S2 is generated based on the voltage difference, and then the signal S2 is output from its output terminal 6b to a second input terminal 8b of the multiplexer or matrix switch 8. The output mode of the transimpedance amplifier 6 can be a single-ended output or a differential output.

The down conversion module 10 includes a first down converter 12 and a second down converter 14. An input 12a of the first down converter 12 is coupled to a first output 8c of the multiplexer or matrix switch 8, so the first down converter 12 can receive the first output of the multiplexer or matrix switch 8. The signal output by terminal 8c. The first down converter 12 can down convert the received signal (for example, convert the RF signal into an intermediate frequency signal or a baseband signal), and filter the desired signal (for example, a signal in a predetermined channel or frequency). ). An input 14a of the second down converter 14 is coupled to a second output 8d of the multiplexer or matrix switch 8, so that the second down converter 14 can receive the second output of the multiplexer or matrix switch 8. The signal output by terminal 8d. The second down converter 14 can down convert the received signal (for example, convert the RF signal into an intermediate frequency signal or a baseband signal), and filter the desired signal (for example, a signal in a predetermined channel or frequency). ).

Referring also to FIG. 2, the multiplexer or matrix switch 8 includes first to fourth switches 16, 18, 20, 22. The first to fourth switches 16, 18, 20, 22 may be four N-type MOS transistors, four P-type MOS transistors or other suitable components. . Hereinafter, the first switch 16, the second switch 18, the third switch 20, and the fourth switch 22 are respectively a first N-type MOS field effect transistor, a second N-type MOS field-effect transistor, and a first An example of a three-N type gold oxide half field effect transistor and a fourth N type gold oxide half field effect transistor will be described. Each of the first to fourth N-type MOS field-effect transistors has a first terminal (eg, a source), a second terminal (eg, a drain), and a third terminal (eg, a gate) And, an N-type channel can be formed to connect the first end point and the second end point. In this example, the output terminal 4b of the low noise amplifier 4 is coupled to the first end of the first N-type MOS field-effect transistor (which is an input terminal 16a of the first switch 16) and the second N-type. a first end of the MOS field effect transistor (which serves as an input terminal 18a of the second switch 18), and an output terminal 6b of the transimpedance amplifier 6 is coupled to the first end of the third N-type MOS field-effect transistor a point (which is an input terminal 20a of the third switch 20) and a first end point of the fourth N-type MOS field-effect transistor (which serves as an input terminal 22a of the fourth switch 22), the first frequency down The input end 12a of the converter 12 is coupled to the second end of the second N-type MOS field-effect transistor (which is an output terminal 18b of the second switch 18) and the fourth N-type MOS field-effect transistor. a second end point (which is an output end 22b of the fourth switch 22), and an input end 14a of the second down converter 14 is coupled to the second end of the first N-type MOS field-effect transistor As an output end 16b of the first switch 16, and a second end of the third N-type MOS field-effect transistor (which is an output terminal 20b of the third switch 20).

The N-type channel of the first N-type gold-oxygen half field effect transistor can be brought into or present in a first conductive state or a first closed state by controlling the third end point of the first N-type metal oxide half field effect transistor. The first conducting state may be related to an input of the second end of the first N-type MOS field-effect transistor to an input of the first end of the first N-type MOS field-effect transistor, wherein the first N-type The input of the first terminal of the MOS field effect transistor is associated with an output of the low noise amplifier 4 (ie, signal S1), such as the input of the first terminal of the first N-type MOS field-effect transistor. This output of the low noise amplifier 4 is low. The first off state electrically disconnects the output of the second end of the first N-type MOS field-effect transistor from the input of the first end of the first N-type MOS field-effect transistor status. For example, in the first conducting state, the signal S1 output by the low noise amplifier 4 is transmitted to the first N-type MOSFET by the first end point and the N-type channel of the first N-type MOS field-effect transistor. a second end of the transistor; in the first off state, the signal S1 output by the low noise amplifier 4 cannot be transmitted to the first N-type gold oxide through the N-type channel of the first N-type MOS field-effect transistor The second end of the half field effect transistor.

The N-type channel of the second N-type MOS field-effect transistor can be brought into or present in a second conductive state or a second closed state by controlling the third terminal of the second N-type MOS field-effect transistor. The second conducting state may be related to an output of the second end of the second N-type MOS field-effect transistor being related to an input of the first end of the second N-type MOS field-effect transistor, wherein the second N-type The input of the first terminal of the MOS field effect transistor is associated with an output of the low noise amplifier 4 (ie, signal S1), such as the input of the first terminal of the second N-type MOS field-effect transistor. This output of the low noise amplifier 4 is low. The second off state electrically disconnects the output of the second end of the second N-type MOS field-effect transistor from the input of the first end of the second N-type MOS field-effect transistor status. For example, in the second conducting state, the signal S1 output by the low noise amplifier 4 is transmitted to the second N-type MOSFET by the first end point and the N-type channel of the second N-type MOS field-effect transistor. The second end of the transistor; in the second off state, the signal S1 output by the low noise amplifier 4 cannot be transmitted to the second N-type gold oxide through the N-type channel of the second N-type metal oxide half field effect transistor The second end of the half field effect transistor.

By controlling the third end point of the third N-type MOS field effect transistor, the N-type channel of the third N-type MOS field-effect transistor can be made to assume a third conduction state or a third OFF state. The third conduction state may be related to an input of the second end of the third N-type MOS field-effect transistor and an input of the first end of the third N-type MOS field-effect transistor, wherein the third N-type The input of the first terminal of the MOS field effect transistor is related to an output of the transimpedance amplifier 6 (ie, signal S2), for example, the input of the first terminal of the third N-type MOS field-effect transistor is equal to the turn This output of the resistive amplifier 6. The third off state electrically disconnects the output of the second end of the third N-type MOS field-effect transistor from the input of the first end of the third N-type MOS field-effect transistor status. For example, in the third conduction state, the signal S2 outputted by the transimpedance amplifier 6 is transmitted to the third N-type MOS half-field power through the first end point and the N-type channel of the third N-type MOS field-effect transistor. The second end of the crystal; in the third off state, the signal S2 outputted by the transimpedance amplifier 6 cannot be transmitted to the third N-type gold-oxygen half-field through the N-type channel of the third N-type MOS field-effect transistor The second end of the transistor.

By controlling the third end point of the fourth N-type MOS field effect transistor, the N-type channel of the fourth N-type MOS field effect transistor can be brought into or assume a fourth conduction state or a fourth OFF state. The fourth conduction state may be related to an input of the second end of the fourth N-type MOS field-effect transistor and an input of the first end of the fourth N-type MOS field-effect transistor, wherein the fourth N-type The input of the first terminal of the MOS field effect transistor is related to an output of the transimpedance amplifier 6 (ie, signal S2), for example, the input of the first terminal of the fourth N-type MOS field-effect transistor is equal to the turn. This output of the resistive amplifier 6. The fourth off state electrically disconnects the output of the second end of the fourth N-type MOS field-effect transistor from the input of the first end of the fourth N-type MOS field-effect transistor status. For example, in the fourth conduction state, the signal S2 outputted by the transimpedance amplifier 6 is transmitted to the fourth N-type MOS half-field power through the first end point and the N-type channel of the fourth N-type MOS field-effect transistor. The second end of the crystal; in the fourth off state, the signal S2 outputted by the transimpedance amplifier 6 cannot be transmitted through the N-type channel of the fourth N-type MOS field-effect transistor to the fourth N-type MOSFET The second end of the transistor.

Therefore, in the present invention, the first to fourth N-type metal oxide half field effect transistors (i.e., the switches 16, 18, 20, and 22) can assume the states described below. For example, the first N-type MOS field effect transistor (ie, the first switch 16) assumes a first conduction state, and the second N-type MOS field effect transistor (ie, the second switch 18) exhibits a second off state, and a third The N-type gold-oxygen half-field effect transistor (ie, the third switch 20) exhibits a third off state, and the fourth N-type gold-oxygen half-field effect transistor (ie, the fourth switch 22) assumes a fourth conduction state; therefore, when the signal processing device When receiving the first and second signals, the multiplexer or matrix switch 8 can receive the signal S1 via the first input terminal 8a (ie, the amplified first signal outputted by the output terminal 4b of the low noise amplifier 4) and The signal S2 is received via the second input terminal 8b (which is derived from the second signal), and then the signal S1 is output from the second output terminal 8d through the first N-type MOS field effect transistor, and the signal S2 is passed through the fourth N-type. The gold oxide half field effect transistor is output from the first output terminal 8c. Alternatively, the first N-type MOS field-effect transistor exhibits a first off state, the second N-type MOS field-effect transistor exhibits a second conduction state, and the third N-type MOS field-effect transistor exhibits a third conduction state. The fourth N-type metal oxide half field effect transistor exhibits a fourth off state; therefore, when the signal processing device 1 simultaneously receives the first and second signals, the multiplexer or matrix switch 8 can be received via the first input terminal 8a. The signal S1 (ie, the amplified first signal) and the signal S2 (which is derived from the second signal) are received via the second input terminal 8b, and then the signal S1 is passed from the first output terminal through the second N-type metal oxide half field effect transistor. The 8c output, the signal S2 is output from the second output terminal 8d through the third N-type metal oxide half field effect transistor. Alternatively, the first N-type gold-oxygen half-field effect transistor exhibits a first conduction state, the second N-type gold-oxygen half-field effect transistor exhibits a second conduction state, and the third N-type gold-oxygen half-field effect transistor exhibits a third closed state. The fourth N-type MOS field effect transistor exhibits a fourth off state; therefore, when the signal processing device 1 receives only the first signal, the multiplexer or matrix switch 8 can receive the signal S1 via the first input terminal 8a ( That is, the amplified first signal), and then the signal S1 is output from the first and second output terminals 8c, 8d through the first and second N-type MOS field-effect transistors. Alternatively, the first N-type gold-oxygen half-field effect transistor exhibits a first off state, the second N-type gold-oxygen half-field effect transistor exhibits a second off state, and the third N-type gold-oxygen half-field effect transistor exhibits a third on state. The fourth N-type MOS field-effect transistor exhibits a fourth conduction state; therefore, when the signal processing device 1 receives only the second signal, the multiplexer or matrix switch 8 can receive the signal S2 via the second input terminal 8b ( It is derived from the second signal), and then the signal S2 is output from the first and second output terminals 8c, 8d through the third and fourth N-type metal oxide half field effect transistors. Alternatively, the first N-type gold-oxygen half-field effect transistor exhibits a first on state, the second N-type gold-oxygen half-field effect transistor exhibits a second off state, and the third N-type gold-oxygen half-field effect transistor exhibits a third off state. The fourth N-type MOS field effect transistor exhibits a fourth off state; therefore, when the signal processing device 1 receives only the first signal, the multiplexer or matrix switch 8 can receive the signal S1 via the first input terminal 8a ( That is, the amplified first signal), and then the signal S1 is output from the second output terminal 8d through the first N-type metal oxide half field effect transistor. Alternatively, the first N-type gold-oxygen half-field effect transistor exhibits a first off state, the second N-type gold-oxygen half-field effect transistor exhibits a second off state, and the third N-type gold-oxygen half-field effect transistor exhibits a third off state. The fourth N-type MOS field-effect transistor exhibits a fourth conduction state; therefore, when the signal processing device 1 receives only the second signal, the multiplexer or matrix switch 8 can receive the signal S2 via the second input terminal 8b ( It is derived from the second signal), and then the signal S2 is output from the first output terminal 8c through the fourth N-type metal oxide half field effect transistor.

In addition, an input of the input end 16a of the first switch 16 can be a differential input, an output of the output end 16b of the first switch 16 can be a differential output, and an input of the input end 18a of the second switch 18 can be For a differential input, an output of the output terminal 18b of the second switch 18 can be a differential output, an input of the input terminal 20a of the third switch 20 can be a differential input, and an output terminal 20b of the third switch 20 An output of the fourth switch 22 can be a differential input, and an output of the output 22b of the fourth switch 22 can be a differential output. When the outputs of the outputs 16b, 18b, 20b, and 22b of the switches 16, 18, 20, and 22 are differential outputs, Common-Mode Noise can be eliminated. Alternatively, an input of the input terminal 16a of the first switch 16 can be a single-ended input, an output of the output terminal 16b of the first switch 16 can be a single-ended output, and an input of the input terminal 18a of the second switch 18 can be For a single-ended input, an output of the output 18b of the second switch 18 can be a single-ended output, an input of the input 20a of the third switch 20 can be a single-ended input, and an output 20b of the third switch 20 An output of the fourth switch 22 can be a single-ended input, and an input of the output 22b of the fourth switch 22 can be a single-ended output.

FIG. 3A is an embodiment of the down converters 12, 14. Referring to FIG. 3A, each of the down converters 12, 14 includes: a frequency synthesizer 24, an in-phase quadrature (I/Q) generator 26, and a pair of mixers. (mixers) 28a and 28b, three variable gain amplifiers (VGA) 30a, 30b and 32, and two filters 34a and 34b. The frequency synthesizer 24 includes: a local oscillator (LO) 24a, such as a Voltage Controlled Oscillator (VCO), and a Phase-Locked Loop (PLL) 24b, such as a fractional lock. Phase loop (fractional PLL). The local oscillator 24a is coupled to the phase locked loop 24b and can generate an output having a periodicity based on the frequency of one of the phase locked loops 24b. The frequency synthesizer 24 is operative to provide or generate a local oscillator signal (i.e., the output of the local oscillator 24a) to the in-phase quadrature generator 26. The in-phase orthogonal generator 26 is a phase shifter that divides the received local oscillation signal into an in-phase (I) component (ie, an in-phase oscillation signal) and a quadrature (Q) component (ie, an orthogonal oscillation signal), and The signals are sent to the mixer 28a and the mixer 28b respectively; the in-phase oscillation signal has the same frequency as the orthogonal oscillation signal, but has a phase difference of 90 degrees. Therefore, the in-phase orthogonal generator 26 can generate two outputs (ie, an in-phase oscillation signal and a quadrature oscillation signal) according to the frequency of one output of the frequency synthesizer 24 (ie, the local oscillation signal), wherein the two outputs have the same frequency. But with a 90 degree phase difference.

In the first down converter 12, an input end of the mixer 28a and an input end of the mixer 28b are coupled to the output end 18b of the second switch 18 and the output end 22b of the fourth switch 22; therefore, A first input of the mixer 28a and a first input of the mixer 28b are selectively associated with an output of the output 18b of the second switch 18 and an output of the output 22b of the fourth switch 22, For example, the first input of the mixer 28a and the first input of the mixer 28b are equal to the output of the output 18b of the second switch 18 or the output of the output 22b of the fourth switch 22. In the second down converter 14, an input end of the mixer 28a and an input end of the mixer 28b are coupled to the output end 16b of the first switch 16 and the output end 20b of the third switch 20; therefore, A first input of the mixer 28a and a first input of the mixer 28b are related to an output of the output 16b of the first switch 16 and an output of the output 20b of the third switch 20, For example, the first input of the mixer 28a and the first input of the mixer 28b are equal to the output of the output 16b of the first switch 16 or the output of the output 20b of the third switch 20.

The mixers 28a and 28b are used for frequency conversion, for example, down-converting a received signal (such as a signal whose frequency is a radio frequency) to a lower frequency (such as a fundamental frequency or an intermediate frequency), wherein the received signal The signal can be from the output 16b, 18b, 20b or 22b. The mixer 28a can receive the in-phase oscillation signal output by the in-phase orthogonal generator 26 (in other words, a second input of the mixer 28a is related to the in-phase oscillation signal output by the in-phase orthogonal generator 26, and the frequency The frequency of the local oscillator signal generated or output by the synthesizer 24 is such that the mixer 28a can be driven by the in-phase oscillator signal output by the in-phase quadrature generator 26. The mixer 28b can receive the orthogonal oscillation signal output by the in-phase orthogonal generator 26 (in other words, a second input of the mixer 28b is related to the orthogonal oscillation signal output by the in-phase orthogonal generator 26, and In relation to the frequency of the local oscillator signal generated or output by the frequency synthesizer 24, the mixer 28b can be driven by the quadrature oscillator signal output by the in-phase quadrature generator 26. Additionally, both mixers 28a and 28b can be differential outputs or single-ended outputs.

In the first down converter 12, the mixer 28a can output the in-phase oscillation signal output by the in-phase orthogonal generator 26 and the output terminal 18b of the second switch 18 or the output terminal 22b of the fourth switch 22 Performing mixing (in other words, the mixer 28a is adapted to mix the first input and the second input of the mixer 28a) to generate and output an in-phase mixed signal; The wave filter 28b can mix the orthogonal oscillation signal output by the in-phase orthogonal generator 26 with the signal output from the output terminal 18b of the second switch 18 or the output terminal 22b of the fourth switch 22 (in other words, the mixed wave The 28b is adapted to mix the first input and the second input of the mixer 28b to generate and output a quadrature mixed signal. The in-phase mixed-wave signal and the quadrature mixed-wave signal are two-phase orthogonal signals, that is, the phase difference between the in-phase mixed-wave signal and the orthogonal mixed-wave signal is 90 degrees; in addition, the in-phase mixed wave signal and the orthogonal mixed wave The signal can be a differential signal or a single-ended signal. Therefore, the first down converter 12 can cause the signals output by the first output terminal 8c of the multiplexer or matrix switch 8 (for example, an output of the output terminal 18b or 22b) to be respectively associated with the mixers 28a and 28b. The two outputs (i.e., the in-phase oscillating signal and the quadrature oscillating signal) generated by the in-phase quadrature generator 26 are mixed to generate an in-phase mixed-wave signal and an orthogonal mixed-wave signal.

In the second down converter 14, the mixer 28a can output the in-phase oscillation signal output by the in-phase orthogonal generator 26 and the output terminal 16b of the first switch 16 or the output terminal 20b of the third switch 20 Mixing is performed (in other words, the mixer 28a is adapted to mix the first input of the mixer 28a with the second input) to generate and output an in-phase mixed wave signal; the mixer 28b can be in phase The orthogonal oscillating signal output by the quadrature generator 26 is mixed with the signal output from the output terminal 16b of the first switch 16 or the output terminal 20b of the third switch 20 (in other words, the mixer 28b is suitable for mixing The first input of the waver 28b is mixed with the second input to generate and output a quadrature mixed signal. The in-phase mixed-wave signal and the quadrature mixed-wave signal are two-phase orthogonal signals, that is, the phase difference between the in-phase mixed-wave signal and the orthogonal mixed-wave signal is 90 degrees; in addition, the in-phase mixed wave signal and the orthogonal mixed wave The signal can be a differential signal or a single-ended signal. Therefore, the second down converter 14 can cause the signals output by the second output terminal 8d of the multiplexer or matrix switch 8 (for example, an output of the output terminal 16b or 20b) to be respectively associated with the mixers 28a and 28b. The two outputs (i.e., the in-phase oscillating signal and the quadrature oscillating signal) generated by the in-phase quadrature generator 26 are mixed to generate an in-phase mixed-wave signal and an orthogonal mixed-wave signal.

An input of the variable gain amplifier 30a is coupled to an output of the mixer 28a. An input of the variable gain amplifier 30a is associated with an output of the mixer 28a (i.e., an in-phase mixed signal), such as the input of the variable gain amplifier 30a being equal to the output of the mixer 28a. The variable gain amplifier 30a can amplify the input of the variable gain amplifier 30a (e.g., the in-phase mixed signal output from the mixer 28a) according to a gain to generate an output (e.g., the amplified in-phase mixed signal). An input of the variable gain amplifier 30b is coupled to an output of the mixer 28b. An input of the variable gain amplifier 30b is associated with an output of the mixer 28b (i.e., a quadrature mixed signal), such as the input of the variable gain amplifier 30b being equal to the output of the mixer 28b. The variable gain amplifier 30b can amplify the input of the variable gain amplifier 30b (for example, the quadrature mixed signal output by the mixer 28b) according to a gain to generate an output (for example, an amplified quadrature mixed signal). .

A first input end and a second input end of the filter 34a are respectively coupled to an output end of the variable gain amplifier 30a and an output end of the variable gain amplifier 30b. A first input of the filter 34a is associated with the output of the mixer 28a (i.e., the in-phase mixed-wave signal) and the output of the variable gain amplifier 30a (e.g., the amplified in-phase mixed-wave signal), such as the filter 34a. This first input is equal to the output of the variable gain amplifier 30a. A second input of filter 34a is associated with the output of mixer 28b (ie, the quadrature mixed signal) and the output of variable gain amplifier 30b (eg, the amplified quadrature mixed signal), such as a filter. This second input of 34a is equal to the output of variable gain amplifier 30b. The filter 34a can combine the first input of the filter 34a (for example, the in-phase mixed signal amplified by the variable gain amplifier 30a) and the second input (for example, the orthogonal mixed signal amplified by the variable gain amplifier 30b). And offsetting a particular signal (eg, a mirror signal) to produce an output, wherein the phase of the output is coupled to the output of the mixer 28a (ie, the in-phase mixed signal) and the output of the variable gain amplifier 30a (eg, after amplification) The in-phase mixed signal is different, and is also different from the output of the mixer 28b (ie, the quadrature mixed signal) and the output of the variable gain amplifier 30b (eg, the amplified quadrature mixed signal). The filter 34a may be an Image Rejection Filter that combines the first input and the second input of the filter 34a to solve the problem of the image signal.

An input of the filter 34b is coupled to an output of the filter 34a. An input of filter 34b is associated with the output of filter 34a, such as the input of filter 34b being equal to the output of filter 34a. Filter 34b may perform filtering on the input of filter 34b (e.g., the signal output by filter 34a) to produce an output (e.g., a signal in a predetermined channel or frequency). Filter 34b can be a channel selection filter that filters out or selects a signal carried in a predetermined channel or frequency. An input of the variable gain amplifier 32 is coupled to an output of the filter 34b. An input of variable gain amplifier 32 is associated with the output of filter 34b (e.g., a signal in a predetermined channel or frequency), such as the input of variable gain amplifier 32 being equal to the output of filter 34b. The variable gain amplifier 32 can amplify the input of the variable gain amplifier 32 (eg, a signal in a predetermined channel or frequency output by the filter 34b) according to a gain to generate an output (such as A or B as shown in FIG. 3A). ). Additionally, the output of variable gain amplifier 32 can be a differential output.

FIG. 3B is another embodiment of the down converters 12, 14. Referring to FIG. 3B, each of the down converters 12, 14 includes a frequency synthesizer 24, a mixer 28a, two variable gain amplifiers 30a and 32, and a filter 34b. The frequency synthesizer 24 includes a local oscillator 24a (e.g., a voltage controlled oscillator) and a phase locked loop 24b (e.g., a fractional phase locked loop). The local oscillator 24a is coupled to the phase locked loop 24b and can generate an output having a periodicity based on the frequency of one of the phase locked loops 24b. The frequency synthesizer 24 is operative to provide or generate a local oscillator signal (i.e., the output of the local oscillator 24a) to the mixer 28a.

In the first down converter 12, an input end of the mixer 28a is coupled to the output 18b of the second switch 18 and the output 22b of the fourth switch 22; therefore, a first input of the mixer 28a is An output of the output 18b of the second switch 18 and an output of the output 22b of the fourth switch 22 are alternatively associated, for example, the first input of the mixer 28a is equal to the output 18b of the second switch 18. The output or the output of the output 22b of the fourth switch 22 is output. In the second down converter 14, an input end of the mixer 28a is coupled to the output 16b of the first switch 16 and the output 20b of the third switch 20; therefore, a first input of the mixer 28a is An output of the output 16b of the first switch 16 and an output of the output 20b of the third switch 20 are alternatively associated, for example, the first input of the mixer 28a is equal to the output 16b of the first switch 16 The output or the output of the output 20b of the third switch 20 is output.

The mixer 28a is configured to perform frequency conversion, for example, down-converting a received signal (such as a signal whose frequency is a radio frequency) to a lower frequency (such as a fundamental frequency or an intermediate frequency), wherein the received signal can be It is from the output 16b, 18b, 20b or 22b. The mixer 28a can receive the local oscillation signal output by the local oscillator 24a of the frequency synthesizer 24 (in other words, a second input of the mixer 28a is related to the frequency of the local oscillation signal output by the local oscillator 24a) The mixer 28a can be driven by a local oscillation signal output from the local oscillator 24a of the frequency synthesizer 24. Additionally, the mixer 28a can be a differential output or a single-ended output.

In the first down converter 12, the mixer 28a can output the local oscillation signal to the local oscillator 24a of the frequency synthesizer 24 and the output terminal 18b of the second switch 18 or the output terminal 22b of the fourth switch 22. The output signal is mixed (in other words, the mixer 28a is adapted to mix the first input of the mixer 28a with the second input) to generate and output a mixed signal. The mixed signal output by the mixer 28a may be a single-ended signal or a differential signal. Therefore, the first down converter 12 can pass the signal output by the first output terminal 8c of the multiplexer or matrix switch 8 (for example, an output of the output terminal 18b or 22b) to the frequency synthesizer 24 through the mixer 28a. The local oscillator signals output by the local oscillator 24a are mixed to generate a mixed signal.

In the second down converter 14, the mixer 28a can output the local oscillation signal to the local oscillator 24a of the frequency synthesizer 24 and the output terminal 16b of the first switch 16 or the output terminal 20b of the third switch 20. The output signal is mixed (in other words, the mixer 28a is adapted to mix the first input of the mixer 28a with the second input) to generate and output a mixed signal. The mixed signal output by the mixer 28a may be a single-ended signal or a differential signal. Therefore, the second down converter 14 can transmit the signal (for example, an output of the output terminal 16b or 20b) of the multiplexer or the second output terminal 8d of the matrix switch 8 to the frequency synthesizer 24 through the mixer 28a. The local oscillator signals output by the local oscillator 24a are mixed to generate a mixed signal.

An input of the variable gain amplifier 30a is coupled to an output of the mixer 28a. An input of the variable gain amplifier 30a is associated with an output of the mixer 28a (i.e., a mixed signal), such as the input of the variable gain amplifier 30a being equal to the output of the mixer 28a. The variable gain amplifier 30a can amplify the input of the variable gain amplifier 30a (e.g., the mixed signal output by the mixer 28a) according to a gain to generate an output (e.g., the amplified mixed signal). An input of the filter 34b is coupled to an output of the variable gain amplifier 30a. An input of filter 34b is associated with the output of variable gain amplifier 30a (e.g., the amplified mixed signal), such as the input of filter 34b being equal to the output of variable gain amplifier 30a. Filter 34b may perform filtering on the input of filter 34b (e.g., the amplified mixed signal output by variable gain amplifier 30a) to produce an output (e.g., a predetermined channel or signal in frequency). Filter 34b can be a channel selection filter that filters out or selects a signal carried in a predetermined channel or frequency. An input of the variable gain amplifier 32 is coupled to an output of the filter 34b. An input of variable gain amplifier 32 is associated with the output of filter 34b (e.g., a signal in a predetermined channel or frequency), such as the input of variable gain amplifier 32 being equal to the output of filter 34b. The variable gain amplifier 32 can amplify the input of the variable gain amplifier 32 (eg, a signal in a predetermined channel or frequency output by the filter 34b) according to a gain to generate an output (such as A or B as shown in FIG. 3B). ). Additionally, the output of variable gain amplifier 32 can be a differential output.

4A, 4B, and 4C illustrate three aspects of the optical receiver 2; these three aspects are for illustrative purposes only and are not intended to limit the scope of the invention. Referring to FIG. 4A, the optical receiver 2 can include a light receiving element 36 and two inductive elements 38a, 38b. The light receiving element 36 has a function of generating an electric signal by receiving light or an optical signal. Hereinafter, a photo diode will be described as an example of the light receiving element 36. However, in addition to the photodiode, other suitable components may be used as an alternative to the light receiving component 36. A positive terminal and a negative terminal of the light receiving component 36 are respectively coupled to a ground terminal (Vss) and a power voltage terminal (Vdd), and the inductor component 38a is coupled to the power voltage terminal (Vdd) and the negative of the light receiving component 36. Between the extremes, the inductive component 38b is coupled between the ground terminal (Vss) and the positive terminal of the light receiving component 36. Each of the inductive components 38a, 38b can be considered a low pass filter to eliminate noise. When the light receiving component 36 (for example, the photodiode) receives a light or an optical signal, the light receiving component 36 generates an electrical signal (ie, the second signal described above) and transmits the signal to the transimpedance amplifier 6; the transimpedance amplifier 6 The electrical signal generated by the light receiving element 36 can be converted into a voltage difference value, and an output signal (ie, the above-mentioned signal S2) is generated according to the voltage difference. In this example, the light receiving element 36 is a differential output to the transimpedance amplifier 6, that is, the transimpedance amplifier 6 can be coupled to the positive and negative terminals of the light receiving element 36, respectively.

The optical receiver 2 may be a single-ended output to the transimpedance amplifier 6 in addition to the differential output to the transimpedance amplifier 6, as shown in FIGS. 4B and 4C. Referring to FIG. 4B, the optical receiver 2 can include a light receiving component 36 (eg, a photodiode) and an inductive component 38. A positive terminal and a negative terminal of the light receiving component 36 are respectively coupled to a ground. The terminal (Vss) and a power supply voltage terminal (Vdd) are coupled between the power supply voltage terminal (Vdd) and the negative terminal of the light receiving component 36. In FIG. 4B, an output 40 of the optical receiver 2 is located between the negative terminal of the light receiving element 36 and the inductive component 38; the transimpedance amplifier 6 can be coupled to the output 40 of the optical receiver 2 to receive light. The electrical signal generated by the component 36 (ie, the second signal described above) is received. Referring to FIG. 4C, the optical receiver 2 can include a light receiving component 36 (eg, a photodiode) and an inductive component 38. A positive terminal and a negative terminal of the light receiving component 36 are respectively coupled to a ground. The terminal (Vss) and a power supply voltage terminal (Vdd), the inductive component 38 is coupled between the ground terminal (Vss) and the positive terminal of the light receiving component 36. In FIG. 4C, an output terminal 40 of the optical receiver 2 is located between the positive terminal of the light receiving element 36 and the inductive component 38; the transimpedance amplifier 6 can be coupled to the output terminal 40 of the optical receiver 2 to receive light. The electrical signal generated by the component 36 (ie, the second signal described above) is received.

In the present invention, the signal processing device 1 can receive only the first signal described above, such as a mixed television signal transmitted by a cable. In the case where the signal processing device 1 receives only the first signal, the first signal is amplified by the low noise amplifier 4 and output to the multiplexer or matrix switch 8, and then amplified by the multiplexer or matrix switch 8. A signal (ie, the signal S1 described above) is transmitted to the down converter 12 or 14, and finally a signal carried by a predetermined channel or frequency is selected from the amplified first signal via the down converter 12 or 14. Alternatively, in the case where the signal processing device 1 receives only the first signal, the first signal is amplified by the low noise amplifier 4 and transmitted to the multiplexer or matrix switch 8, and then amplified by the multiplexer or matrix switch 8. The first signal is simultaneously transmitted to the down converters 12 and 14 (that is, the multiplexer or matrix switch 8 simultaneously outputs the amplified first signal to the down converters 12 and 14), and finally to the down converter 12 And 14 select a signal carried by a predetermined channel or frequency.

In addition, the signal processing device 1 may also receive only the second signal described above, such as the signal generated by the optical receiver 2. In the case where the signal processing device 1 receives only the second signal, the second signal is amplified by the transimpedance amplifier 6 and output to the multiplexer or matrix switch 8, and then the second amplified by the multiplexer or matrix switch 8. The signal (ie, the signal S2 described above) is transmitted to the down converter 12 or 14, and finally the signal carried by the predetermined channel or frequency is selected from the amplified second signal via the down converter 12 or 14. Alternatively, in the case where the signal processing device 1 receives only the second signal, the second signal is amplified by the transimpedance amplifier 6 and output to the multiplexer or matrix switch 8, and then amplified by the multiplexer or matrix switch 8. The second signal is simultaneously transmitted to the down converters 12 and 14 (that is, the multiplexer or matrix switch 8 simultaneously outputs the amplified second signal to the down converters 12 and 14), and finally via the down converter 12 14 Select a signal carried by a predetermined channel or frequency.

In addition to the case where only the first or second signal is received, the signal processing device 1 can simultaneously receive the first and second signals described above. In the case that the signal processing device 1 simultaneously receives the first and second signals, the first signal and the second signal are respectively amplified by the low noise amplifier 4 and the transimpedance amplifier 6 and output to the multiplexer or matrix switch 8, and then The amplified first and second signals are respectively transmitted to the down converters 12 and 14 via the multiplexer or matrix switch 8, and finally from the amplified first or second signals via the down converter 12 or 14. Select a signal carried by a predetermined channel or frequency.

The invention can integrate the low noise amplifier 4, the transimpedance amplifier 6, the multiplexer or matrix switch 8 and the down conversion module 10 on a chip, so that the circuit can be modularly designed to avoid Poorly matched conditions result in reduced circuit design and cost. In addition, the integration of these circuits on a wafer reduces production costs and reduces the size of the device.

The above description of the embodiments of the present invention is intended to be understood by those skilled in the art, and the invention may be practiced without departing from the scope of the invention. Equivalent modifications or modifications made by the spirit of the invention should still be included in the scope of the claims described below.

1‧‧‧Signal Processing Unit
2‧‧‧Light Receiver
4‧‧‧Low noise amplifier
4a‧‧‧ input
4b‧‧‧output
6‧‧‧Transistor amplifier
6a‧‧‧ input
6b‧‧‧output
8‧‧‧Multiplexer or matrix switch
8a‧‧‧ first input
8b‧‧‧second input
8c‧‧‧ first output
8d‧‧‧second output
10‧‧‧ Down Conversion Module
12‧‧‧First down converter
12a‧‧‧ input
14‧‧‧Second down converter
14a‧‧‧ input
16‧‧‧First switch
16a‧‧‧ input
16b‧‧‧output
18‧‧‧second switch
18a‧‧‧ input
18b‧‧‧output
20‧‧‧third switch
20a‧‧‧ input
20b‧‧‧output
22‧‧‧fourth switch
22a‧‧‧ input
22b‧‧‧output
24‧‧‧ frequency synthesizer
24a‧‧‧Local Oscillator
24b‧‧‧ phase-locked loop
26‧‧‧In-phase orthogonal generator
28a‧‧‧Mixer
28b‧‧‧Mixer
30a‧‧‧Variable Gain Amplifier
30b‧‧‧Variable Gain Amplifier
32‧‧‧Variable Gain Amplifier
34a‧‧‧Filter
34b‧‧‧Filter
36‧‧‧Light receiving components
38‧‧‧Inductive components
38a‧‧‧Inductance components
38b‧‧‧Inductive components
40‧‧‧output
S1‧‧‧ output signal
S2‧‧‧ output signal
A‧‧‧ output
B‧‧‧ output

Figure 1 is a schematic diagram of a signal processing device of the present invention. Figure 2 is a circuit diagram of a multiplexer or matrix switch of the present invention. FIG. 3A is a circuit diagram of a down conversion module of the present invention. FIG. 3B is a circuit diagram of a down conversion module of the present invention. 4A is a schematic diagram of a photo diode bias network of the present invention. 4B is a schematic view of a photodiode biasing circuit of the present invention. 4C is a schematic view of a photodiode biasing circuit of the present invention.

While certain embodiments have been illustrated in the drawings, the embodiments of the invention And other embodiments described herein.

1‧‧‧Signal Processing Unit

2‧‧‧Light Receiver

4‧‧‧Low noise amplifier

4a‧‧‧ input

4b‧‧‧output

6‧‧‧Transistor amplifier

6a‧‧‧ input

6b‧‧‧output

8‧‧‧Multiplexer or matrix switch

8a‧‧‧ first input

8b‧‧‧second input

8c‧‧‧ first output

8d‧‧‧second output

10‧‧‧ Down Conversion Module

12‧‧‧First down converter

12a‧‧‧ input

14‧‧‧Second down converter

14a‧‧‧ input

A‧‧‧ output

B‧‧‧ output

Claims (12)

A signal processing device includes: a low noise amplifier; a transimpedance amplifier; a first switch, an input of the first switch is related to an output of the low noise amplifier, and the first switch can present a first An on state or a first off state, the first on state may be related to an output of the first switch being related to the input of the first switch, the first off state enabling the output of the first switch to be the same a state of being electrically disconnected between the inputs of a switch; a second switch, an input of the second switch being related to the output of the low noise amplifier, the second switch being capable of exhibiting a second conductive state or a a second off state, wherein the second switch can cause an output of the second switch to be related to the input of the second switch, the second off state to enable the output of the second switch and the second switch a state of being electrically disconnected between the inputs; a third switch, an input of the third switch being related to an output of the transimpedance amplifier, the third switch being capable of exhibiting a third conductive state or a third closed state The third The pass state may cause an output of the third switch to be associated with the input of the third switch, the third closed state electrically disconnecting the output of the third switch from the input of the third switch a fourth switch, an input of the fourth switch is related to the output of the transimpedance amplifier, and the fourth switch can assume a fourth conductive state or a fourth closed state, and the fourth conductive state can An output of the fourth switch is related to the input of the fourth switch, and the fourth closed state is capable of electrically disconnecting between the output of the fourth switch and the input of the fourth switch; The down converter includes a first mixer and a first frequency synthesizer, wherein a first input of the first mixer is related to the output of the second switch or the output of the fourth switch, a second input of the first mixer is related to a frequency output by one of the first frequency synthesizers, the first mixer being adapted to mix the first input of the first mixer with the first The second input of the waver is mixed to produce an output; a second down converter comprising a second mixer and a second frequency synthesizer, wherein a first input of the second mixer and the output of the first switch or the third switch Outputting, a second input of the second mixer is related to a frequency output by one of the second frequency synthesizers, the second mixer being adapted to the first input of the second mixer The second input of the second mixer is mixed to produce an output. The signal processing device of claim 1, wherein the low noise amplifier, the transimpedance amplifier, the first down converter, the second down converter, the first switch, the second The switch, the third switch, and the fourth switch are integrated circuits on a single semiconductor wafer. The signal processing device of claim 1, wherein the first down converter further comprises a first in-phase quadrature (I/Q) generator, the first in-phase orthogonal generator is adapted to Generating a first output according to a frequency of the output of the first frequency synthesizer, the second input of the first mixer being related to the first output of the first in-phase orthogonal generator, the second drop The frequency converter further includes a second non-inverting quadrature generator, wherein the second in-phase quadrature generator is adapted to generate a first output according to a frequency of the output of the second frequency synthesizer, the second mixer The second input is associated with the first output of the second in-phase quadrature generator. The signal processing device of claim 3, wherein the first down converter further comprises a third mixer, a first input of the third mixer and the first mixer The first input is identical, the first in-phase orthogonal generator is adapted to generate a second output according to a frequency of the output of the first frequency synthesizer, the first output of the first in-phase orthogonal generator The second output has the same frequency but a 90 degree phase difference, and a second input of the third mixer is associated with the second output of the first in-phase quadrature generator, the second down converter is further A fourth mixer is included, a first input of the fourth mixer is the same as the first input of the second mixer, and the second in-phase orthogonal generator is adapted to be based on the second frequency synthesizer The output frequency produces a second output, the first output of the second in-phase quadrature generator has the same frequency as the second output but has a phase difference of 90 degrees, and a second input of the fourth mixer Associated with the second output of the second in-phase quadrature generator. The signal processing device of claim 1, wherein the first frequency synthesizer comprises a first local oscillator and a first phase locked loop, the first local oscillator being adapted to be based on the first phase lock The frequency of one of the outputs of the loop produces an output having a periodicity, the second input of the first mixer being related to the frequency of the output of the first local oscillator, the second frequency synthesizer comprising a second local An oscillator and a second phase locked loop, the second local oscillator being adapted to generate an output having a periodicity according to a frequency output by one of the second phase locked loops, the second input of the second mixer The frequency of the output of the second local oscillator is related. The signal processing device of claim 1, wherein the first down converter further comprises a first channel selection filter, and one of the first channel selection filters is input to the first mixer. The output is related to, and the first channel selection filter is adapted to filter the input of the first channel selection filter to generate an output, and the second down converter further comprises a second channel selection filter, the second One of the channel selection filters is associated with the output of the second mixer, and the second channel selection filter is adapted to filter the input of the second channel selection filter to produce an output. The signal processing device of claim 1, wherein the first down converter further includes a first channel selection filter, a first variable gain amplifier, and a second variable gain amplifier. An input of a variable gain amplifier is associated with the output of the first mixer, the first variable gain amplifier being adapted to amplify the input of the first variable gain amplifier to generate an output according to a first gain, One of the first channel selection filters is associated with the output of the first variable gain amplifier, the first channel selection filter being adapted to filter the input of the first channel selection filter to produce an output, the An input of the second variable gain amplifier is associated with the output of the first channel selection filter, the second variable gain amplifier being adapted to amplify the input of the second variable gain amplifier to generate an output according to a second gain The second down converter further includes a second channel selection filter, a third variable gain amplifier, and a fourth variable gain amplifier, the third variable gain amplifier An input is associated with the output of the second mixer, the third variable gain amplifier being adapted to amplify the input of the third variable gain amplifier to generate an output according to a third gain, the second channel selective filtering One of the inputs is associated with the output of the third variable gain amplifier, the second channel selection filter is adapted to filter the input of the second channel selection filter to produce an output, the fourth variable gain amplifier An input is associated with the output of the second channel select filter, the fourth variable gain amplifier being adapted to amplify the input of the fourth variable gain amplifier to generate an output in accordance with a fourth gain. The signal processing device of claim 1, wherein the transimpedance amplifier is configured to receive a differential input. The signal processing device of claim 1, wherein the low noise amplifier is configured to receive a first input, and the first input is related to a first signal transmitted by a coaxial cable, and the transimpedance amplifier is used. Receiving a second input, the second input is related to a second signal generated by a light receiver. The signal processing device of claim 1, wherein the signal processing device is disposed on a television set or a set top box. The signal processing device of claim 1, wherein the input of the first switch is a differential input, the output of the first switch is a differential output, and the input of the second switch is a a differential input, the output of the second switch is a differential output, the input of the third switch is a differential input, the output of the third switch is a differential output, and the input of the fourth switch For a differential input, the output of the fourth switch is a differential output. The signal processing device of claim 1, wherein the input of the first switch is a single-ended input, the output of the first switch is a single-ended output, and the input of the second switch is a Single-ended input, the output of the second switch is a single-ended output, the input of the third switch is a single-ended input, the output of the third switch is a single-ended output, the input of the fourth switch For a single-ended input, the output of the fourth switch is a single-ended output.