Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA. DETAILED ACTION This office action is in regards to application # 18/465,178 that was filed on 09/12/2023. Claims 1-20 are currently pending and are under examination. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claim s 1-20 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Independent claim 1, the term "dual-wavelength phase range finder" is not clear, because it appears that only one wavelength seem to be used for ranging: The local and measurement beams have the same invisible wavelength, and the visible wavelength is not used for ranging, but only for aiming. Appropriate correction/clarification required. It is not clear from the recitation in Claim 1 how the phase of a signal is used to determine the range. Appropriate correction/clarification required. It is not clear from the recitation in Claim 1 how the range can be determined "based on the first low-frequency signal and the second low-frequency signal". Appropriate correction/clarification required. The same rejection also applies to independent claims 11 and 18. It is not clear from the recitation in Claim 1 what the reference signal is in terms of features recited in the claim , in particular whether it is an electric or optical signal. If it is an optical signal, then what is the difference to the signal of the local path, and if it is an electric signal, then how can it be mixed with a received optical signal? Appropriate correction/clarification required. The same rejection also applies to independent claims 11 and 18. It is not clear from the recitation in Claim 1 how the first and second low-frequency signals can be obtained at what appears to be the same signal path. It appears that some form of multiplexing would have to be involved, but this is left unclear. Appropriate correction/clarification required. The same rejection also applies to independent claims 11 and 18. Independent claim 11, the term "dual-wavelength phase range finder" is not clear, because it appears that only one wavelength seem to be used for ranging: The local and measurement beams have the same invisible wavelength, and the visible wavelength is not used for ranging, but only for aiming. Appropriate correction/clarification required. It is not clear from the recitation in Claim 11 how the phase of a signal is used to determine the range. Appropriate correction/clarification required. Independent claim 18, the term "dual-wavelength phase range finder" is not clear, because it appears that only one wavelength seem to be used for ranging: The local and measurement beams have the same invisible wavelength, and the visible wavelength is not used for ranging, but only for aiming. Appropriate correction/clarification required. It is not clear from the recitation in Claim 18 how the phase of a signal is used to determine the range. Appropriate correction/clarification required. All dependent claims are rejected under the same rational as the rejection of the rejected parent claims above solely based on their dependency from the rejected parent claims. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claim(s) 1 -2, and 4-8, and 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hu et al. (US 2021/0247495 ) in view of Dunne (US 2014/0071432) . Regarding Claim 1 , as best understood, Hu discloses a dual-wavelength phase range finder ( para. [ 0041 ] : "laser radar system", see fig. 1 ), comprising: an emitting device ( para. [ 0112 ] : "After the first master oscillator signal is loaded on the first laser diode, a first laser beam frequency-modulated by the first master oscillator signal is emitted", see fig. 10 ), a receiving device, and a processing device ( para. [ 0113 ] : "The optical signal detection module of the laser radar comprises a photodetector. [...]. The low-frequency electrical signal is amplified by an amplifier circuit 3 and converted by an analog-to-digital converter, to output a low-frequency digital electrical signal (represented by eD) to a Field-Programmable Gate Array (FPGA)", see fig. 10 ); wherein the emitting device comprises a frequency synthesizing device, a laser processing device, and a laser aiming device; and the laser processing device is connected between the frequency synthesizing device and the laser aiming device; the processing device is configured to control the frequency synthesizing device to generate a high-frequency modulation signal and a reference signal; the high- frequency modulation signal passes through the laser processing device to define an outer optical path emitted to a target and define an inner optical path emitted to a filtering device of the receiving device ( para. [0043]: "the high-frequency modulation signal output unit 10 is configured to output at least two preset high-frequency modulation signals with different frequencies; the laser emitting unit 20 is connected to the high-frequency modulation signal output unit 10, and configured to emit at least two laser beams with different frequencies respectively modulated by the at least two preset high-frequency modulation signals with different frequencies; the reference signal transmitting unit 30 is connected to the high-frequency modulation signal output unit 10 and configured to emit at least two reference signals with different frequencies after being respectively modulated by the at least two preset high-frequency modulation signals with different frequencies", see fig. 10 ), the outer optical path is configured to emit a first invisible light signal, the inner optical path is configured to emit a second invisible light signal, and a wavelength of the first invisible light signal is equal to a wavelength of the second invisible light signal ( para. [0065]: "the light emitting module emits a laser beam modulated by a high-frequency modulation signal as a detection optical signal and a reference optical signal, respectively, wherein the optical signal is reflected by the target object to form an echo signal related to the distance of the target object" , wherein para. [0057]: "the laser emitting unit 20 comprises a laser diode, such as a low-power continuous laser diode in the infrared band" ); the receiving device comprises the filtering device, a receiver, and a signal-transmitting circuit; the filtering device is configured to allow a first reflecting light signal and the second invisible light signal to pass through, and the first reflecting light signal is obtained by reflecting the first invisible light signal after the first invisible light signal is irradiated onto the target ( para. [0102]: "the signal receiving unit 40 may further comprise a receiving lens 213 and a filter 214, and the receiving lens 213, the filter 214, and the photodetector 211 are sequentially arranged along the propagation direction of the light beam; [...]; the filter 214 is configured to let the first high-frequency echo signal and the second high-frequency echo signal pass through to filter out interference signals of other wavelengths", see fig. 8); the processing device is further configured to control the first invisible light signal and the reference signal to undergo a photoelectric frequency mixing process at the receiver, thereby to obtain a first low-frequency signal; the processing device is further configured to control the second invisible light signal and the reference signal to undergo the photoelectric frequency mixing process at the receiver, thereby to obtain a second low-frequency signal; and the first low-frequency signal and the second low-frequency signal are transmitted to the processing device through the signal-transmitting circuit; and the processing device is configured to determine a distance between the dual-wavelength phase range finder and the target based on the first low-frequency signal and the second low-frequency signal ( para. [0081]: "The signal processing unit 50 is configured to obtain a first reference distance value of the target object according to a first phase difference between the first reference signal and the first high-frequency echo signal, acquire a second reference distance value of the target object according to the first reference distance value and the second reference distance value, and determine a measurement distance value of the target object according to the first reference distance value and the second reference distance value; wherein the second phase difference is a phase difference between the second reference signal and the second high-frequency echo signal" ). H u is do not explicitly discloses , but Dunne teaches a processing device is configured to control the laser aiming device to emit a visible light signal for aiming at the target and a filtering device is configured to block a second reflecting light signal, and the second reflecting light signal is obtained by reflecting the ·visible light signal after the visible light signal is irradiated onto the target ( para. [0025]: "The instrument 100 also comprises a phase-based, continuous wave, visible light source 118 [...]. Of the approximately 4% of the visible light incident upon the reflective surface 128 something on the order of about 0.2% is then redirected back towards the other side of the dichroic mirror 122 and then redirected 90° towards a viewer/user of the instrument 100 along path 130 and through viewing aperture 132", see fig. 1 and 2 ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase range finder disclosed in H u with the phase-based continuous wave visible light source control and filtering taught i n Dunne with a reasonable expectation of success because it permits precision target acquisition, improved signal-to-noise ratio, and enhanced usability . The modified device would have emitted visible light as claimed, which would have been filtered by the already existing bandpass filter as claimed. Regarding Claim 2 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein a wavelength of the visible light signal is smaller than the wavelength of the first invisible light signal ( Hu discloses emitting invisible IR light as cited above, which has a wavelength higher than that of visible light ) . Regarding Claim 4 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( Hu, para. [0041]: "laser radar system", see fig. 1 ) wherein the dual-wavelength phase range finder further comprises a bias circuit configured to generate and supply a bias voltage to the receiver under control of the processing device, and a first end of the bias circuit is connected to the processing device and a second end of the bias circuit is connected to the receiver ( para. [0069], Fig. 7C, ‘TX_BIAS’ ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase range finder disclosed in Hu with the bias circuit taught in Dunne with a reasonable expectation of success because it permits dynamic, real-time optimization of the operating point (Q-point), improving stability against value shifts and component variability. By controlling the bias, the processor can optimize for high linearity, power efficiency, or low-noise performance, while also enabling rapid adaptation to changing input signal conditions . Regarding Claim 5 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( Hu, p ara. [0041]: "laser radar system", see fig. 1 ) with a display device configured to display data ( para. [0167]: "two-dimensional detection point cloud image data can be displayed" ). Dunne also discloses a display device configured to display the distance, and the display device is connected to the processing device. ( Dunne , para. [0043]: "Information regarding distance to a target point as well as other user information such as battery status, head-up display, aiming reticule, operational mode and the like may be displayed in a liquid crystal display (LCD) 446", see fig. 4 ). Regarding Claim 6, as best understood, Hu is do not explicitly discloses, but Dunne teaches a range finding equipment wherein the receiver comprises an avalanche photodiode (APD) ( para. [0069]: "avalanche photodiode (APO)", see fig. 7C ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the receiver of phase range finder disclosed in Hu with the avalanche photodiode taught in Dunne with a reasonable expectation of success because it provides superior sensitivity, internal gain, and rapid response times compared to standard photodiodes. Regarding Claim 7 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein the frequency synthesizing device comprises a direct digital synthesizer (DDS) circuit ( Hu, para. [0051]: "a Direct Digital Synthesizer (ODS) may be used in the high-frequency modulation signal unit 10” ). Regarding Claim 8 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein the laser processing device comprises a laser driving circuit and laser diodes ( Hu, para. [0129]: "a constant current and constant voltage and constant power driving circuit (not shown in FIG. 10) is also used to provide a stable power supply system for the laser emitting unit (including the first laser diode and the second laser diode), while the voltage feedback of the laser emitting unit itself is used to stabilize the working point of the laser emitting unit" ). Regarding Claim 10 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( Hu, para. [0041]: "laser radar system", see fig. 1 ) wherein the wavelength of the first invisible light signal and the wavelength of the second invisible light signal are both greater than 760 nm ( Hu. para. [0057]: "the laser emitting unit 20 comprises a laser diode, such as a low-power continuous laser diode in the infrared band" ) and wherein a wavelength of the visible light signal is in a range of 440 nanometers (nm) to 580 nm, ( Dunne, para. [0025], visible light signals implicitly range from about 380nm to about 750nm ).. Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over modified Hu et al. (US 2021/0247495) in view of Gaalema et al. (US 2020/0256961). Regarding Claim 3, as best understood, modified Hu discloses a signal amplification using an operational low frequency amplifier/ amplifier circuit ( see Hu, para. [0105] ) recited in claim 3 . Modified Hu is silent about the operational amplifier being of a transconductance type, but Gaalema teaches an operational amplifier being of a transconductance ( see para. [0099] ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the amplifier disclosed in the phase range finder disclosed in modified Hu with the transconductance operational amplifier taught in Gaalema with a reasonable expectation of success because it provides distinct advantages like electrically tunable gain, high-speed operation, and excellent linear voltage-to-current conversion. Claim(s) 11 -13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hu et al. (US 2021/0247495) in view of Gaalema et al. (US 2020/0256961). Regarding Claim 11 , as best understood, Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein the dual-wavelength phase range finder comprises a frequency synthesizing device, a processing device, a laser processing device, a bias circuit ( para. [0069], Fig. 7C, ‘TX_BIAS’ ), a laser aiming device, and a receiving device( para. [0113]: "The optical signal detection module of the laser radar comprises a photodetector. [...]. The low-frequency electrical signal is amplified by an amplifier circuit 3 and converted by an analog-to-digital converter, to output a low-frequency digital electrical signal (represented by eD) to a Field-Programmable Gate Array (FPGA)", see fig. 10 ); wherein the laser aiming device is connected to the frequency synthesizing device through the laser processing device( para. [0043]: "the high-frequency modulation signal output unit 10 is configured to output at least two preset high-frequency modulation signals with different frequencies; the laser emitting unit 20 is connected to the high-frequency modulation signal output unit 10, and configured to emit at least two laser beams with different frequencies respectively modulated by the at least two preset high-frequency modulation signals with different frequencies; the reference signal transmitting unit 30 is connected to the high-frequency modulation signal output unit 10 and configured to emit at least two reference signals with different frequencies after being respectively modulated by the at least two preset high-frequency modulation signals with different frequencies", see fig. 10 ); wherein a first end of the bias circuit is connected to the processing device, and a second end of the bias circuit is connected to a receiver of the receiving device( para. [0069], Fig. 7C, ‘TX_BIAS’ ); wherein the processing device is configured to control the frequency synthesizing device to generate a high-frequency modulation signal and a reference signal, and the high-frequency modulation signal is processed through the laser processing device to emit a first invisible light signal and a second invisible light signal; the processing device is further configured to control the laser aiming device to emit a visible light signal; the visible light signal is configured to aim a target and obtain a second reflecting light signal reflected by the target; the first invisible light signal is configured to irradiated onto the target and obtain a first reflecting light signal reflected by the target; and the second invisible light signal is configured to emitted to a filtering device of the receiving device ( para. [0043]: "the high-frequency modulation signal output unit 10 is configured to output at least two preset high-frequency modulation signals with different frequencies; the laser emitting unit 20 is connected to the high-frequency modulation signal output unit 10, and configured to emit at least two laser beams with different frequencies respectively modulated by the at least two preset high-frequency modulation signals with different frequencies; the reference signal transmitting unit 30 is connected to the high-frequency modulation signal output unit 10 and configured to emit at least two reference signals with different frequencies after being respectively modulated by the at least two preset high-frequency modulation signals with different frequencies", see fig. 10 ); wherein the receiving device comprises the filtering device, the receiver ; wherein the filtering device is configured to allow the first reflecting light signal and the second invisible light signal to pass there-through, and filter-out the second reflecting light signal( para. [0102]: "the signal receiving unit 40 may further comprise a receiving lens 213 and a filter 214, and the receiving lens 213, the filter 214, and the photodetector 211 are sequentially arranged along the propagation direction of the light beam; [...]; the filter 214 is configured to let the first high-frequency echo signal and the second high-frequency echo signal pass through to filter out interference signals of other wavelengths", see fig. 8); wherein the processing device is further configured to control the receiver to perform a photoelectric frequency mixing process on the first reflecting light signal and the reference signal to obtain a first low-frequency signal, and control the receiver to perform the photoelectric frequency mixing process on the second reflecting light signal and the reference signal to obtain a second low-frequency signal; and wherein the first low-frequency signal and the second low-frequency signal are transmitted to the processing device through the amplifier and the low-frequency bandpass amplification circuit, and the processing device is further configured to determine a distance between the dual-wavelength phase range finder and the target based on the first low-frequency signal and the second low-frequency signal ( para. [0081]: "The signal processing unit 50 is configured to obtain a first reference distance value of the target object according to a first phase difference between the first reference signal and the first high-frequency echo signal, acquire a second reference distance value of the target object according to the first reference distance value and the second reference distance value, and determine a measurement distance value of the target object according to the first reference distance value and the second reference distance value; wherein the second phase difference is a phase difference between the second reference signal and the second high-frequency echo signal" ). modified Hu discloses a signal amplification using an operational low frequency amplifier/amplifier circuit ( see Hu, para. [0105] ) recited in claim 3. Modified Hu is silent about the operational amplifier being of a transconductance type, but Gaalema teaches an operational amplifier being of a transconductance ( see para. [0099] ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the low frequency amplifier disclosed in the phase range finder disclosed in Hu with the transconductance operational amplifier taught in Gaalema with a reasonable expectation of success because it provides distinct advantages like electrically tunable gain, high-speed operation, and excellent linear voltage-to-current conversion. Regarding Claim 12 , modified Hu discloses the claimed dual-wavelength phase range finder ( Hu, para. [0041]: "laser radar system", see fig. 1 ) wherein a wavelength of the first invisible light signal is equal to a wavelength of the second invisible light signal (( para. [0102]: "the signal receiving unit 40 may further comprise a receiving lens 213 and a filter 214, and the receiving lens 213, the filter 214, and the photodetector 211 are sequentially arranged along the propagation direction of the light beam; [...]; the filter 214 is configured to let the first high-frequency echo signal and the second high-frequency echo signal pass through to filter out interference signals of other wavelengths", see fig. 8; i.e., the frequencies have to be the same to pass through the filter and not get filtered out ) . Regarding Claim 13 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein a wavelength of the visible light signal is smaller than the wavelength of the first invisible light signal ( Hu discloses emitting invisible IR light as cited above, which has a wavelength higher than that of visible light ). Claim(s) 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over modified Hu et al. (US 2021/0247495) in view of Herman et al. (US 2020/0232895). Regarding Claim 9 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ), with visible light signal ( Dunne, para. [0025] ) . Modified Hu is silent about the color of the visible light signal is green, blue, or red., but Herman teaches an optical sensor with color of the visible light signal is green, blue, or red ( para. [0035], “…The optical sensor 28 may detect one or more wavelengths, such as red, blue, green, visible light, near infrared, ultraviolet, etc….” ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the visible light signal in the phase range finder disclosed in modified Hu with the green, blue or red visible light signals taught in Herman with a reasonable expectation of success because green is best for high daytime visibility, red is ideal for low-light/short-range and power efficiency, and blue is excellent for precision on dark surfaces. Claim(s) 14 -1 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over modified Hu et al. (US 2021/0247495) in view of Dunne (US 2014/0071432). Regarding Claim 14, as best understood, modified Hu is do not explicitly discloses, but Dunne teaches a range finding equipment wherein the receiver comprises an avalanche photodiode (APD) ( para. [0069]: "avalanche photodiode (APO)", see fig. 7C ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the receiver of phase range finder disclosed in modified Hu with the avalanche photodiode taught in Dunne with a reasonable expectation of success because it provides superior sensitivity, internal gain, and rapid response times compared to standard photodiodes. Regarding Claim 15 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein the frequency synthesizing device comprises a direct digital synthesizer (DDS) circuit ( Hu, para. [0051]: "a Direct Digital Synthesizer (ODS) may be used in the high-frequency modulation signal unit 10” ). Regarding Claim 16 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein the laser processing device comprises a laser driving circuit and laser diodes ( Hu, para. [0129]: "a constant current and constant voltage and constant power driving circuit (not shown in FIG. 10) is also used to provide a stable power supply system for the laser emitting unit (including the first laser diode and the second laser diode), while the voltage feedback of the laser emitting unit itself is used to stabilize the working point of the laser emitting unit" ). Regarding Claim 17 , modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein the filtering device comprises a wavelength filter ( para. [0102] ) . Claim(s) 18 -19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hu et al. (US 2021/0247495) in view of Dunne (US 2014/0071432) and further view of Gaalema et al. (US 2020/0256961). Regarding Claim 18 , as best understood, Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) comprising: an emitting device ( para. [0112]: "After the first master oscillator signal is loaded on the first laser diode, a first laser beam frequency-modulated by the first master oscillator signal is emitted", see fig. 10 ), a receiving device, and a processing device ( para. [0113]: "The optical signal detection module of the laser radar comprises a photodetector. [...]. The low-frequency electrical signal is amplified by an amplifier circuit 3 and converted by an analog-to-digital converter, to output a low-frequency digital electrical signal (represented by eD) to a Field-Programmable Gate Array (FPGA)", see fig. 10 ); wherein the emitting device comprises a frequency synthesizing device, a laser processing device, a laser aiming device, and an emitting optical system( Fig. 1, para. [0043]: "the high-frequency modulation signal output unit 10 is configured to output at least two preset high-frequency modulation signals with different frequencies; the laser emitting unit 20 is connected to the high-frequency modulation signal output unit 10, and configured to emit at least two laser beams with different frequencies respectively modulated by the at least two preset high-frequency modulation signals with different frequencies; the reference signal transmitting unit 30 is connected to the high-frequency modulation signal output unit 10 and configured to emit at least two reference signals with different frequencies after being respectively modulated by the at least two preset high-frequency modulation signals with different frequencies", see fig. 10 ); wherein the receiving device comprises a receiving optical system, a filtering device, a receiver, w herein the processing device is configured to control the frequency synthesizing device to generate a high-frequency modulation signal and a reference signal ( para. [0043], see Fig. 10 ); the laser processing device is configured to process the high-frequency modulation signal to emit a first invisible light signal and a second invisible light signal (para. [0065]); the emitting optical system is configured to receive the first invisible light signal from the laser processing device and irradiate the first invisible light signal onto the target and obtain a first reflecting light signal reflected by the target (para. [006 5]); the filtering device is configured to allow the first reflecting light signal and the second invisible light signal to pass there-through ; and the receiving optical system is configured to receive the first reflecting light signal and the second invisible light signal from the filtering device, and focus the first reflecting light signal and the second invisible light signal to the receiver( para. [0102]: "the signal receiving unit 40 may further comprise a receiving lens 213 and a filter 214, and the receiving lens 213, the filter 214, and the photodetector 211 are sequentially arranged along the propagation direction of the light beam; [...]; the filter 214 is configured to let the first high-frequency echo signal and the second high-frequency echo signal pass through to filter out interference signals of other wavelengths", see fig. 8); wherein the processing device is further configured to control the receiver to perform a photoelectric frequency mixing process on the first reflecting light signal and the reference signal to obtain a first low-frequency signal, and control the receiver to perform the photoelectric frequency mixing process on the second reflecting light signal and the reference signal to obtain a second low-frequency signal; and wherein the first low-frequency signal and the second low-frequency signal are transmitted to the processing device through the transconductance amplification circuit and the low-frequency bandpass amplification circuit, and the processing device is further configured to determine a distance between the dual-wavelength phase range finder and the target based on the first low-frequency signal and the second low-frequency signal( para. [0081]: "The signal processing unit 50 is configured to obtain a first reference distance value of the target object according to a first phase difference between the first reference signal and the first high-frequency echo signal, acquire a second reference distance value of the target object according to the first reference distance value and the second reference distance value, and determine a measurement distance value of the target object according to the first reference distance value and the second reference distance value; wherein the second phase difference is a phase difference between the second reference signal and the second high-frequency echo signal" ). Hu is do not explicitly discloses, but Dunne teaches a processing device configured to control the laser aiming device to emit a visible light signal; the visible light signal is configured to aim a target and obtain a second reflecting light signal reflected by the target and a filtering device is configured to filter-out the second reflecting light signal. ( para. [0025]: "The instrument 100 also comprises a phase-based, continuous wave, visible light source 118 [...]. Of the approximately 4% of the visible light incident upon the reflective surface 128 something on the order of about 0.2% is then redirected back towards the other side of the dichroic mirror 122 and then redirected 90° towards a viewer/user of the instrument 100 along path 130 and through viewing aperture 132", see fig. 1 and 2 ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the phase range finder disclosed in Hu with the phase-based continuous wave visible light source control and filtering taught in Dunne with a reasonable expectation of success because it permits precision target acquisition, improved signal-to-noise ratio, and enhanced usability. The modified device would have emitted visible light as claimed, which would have been filtered by the already existing bandpass filter as claimed. modified Hu discloses a signal amplification using an operational low frequency amplifier/amplifier circuit ( see Hu, para. [0105] ) recited in claim 3. Modified Hu is silent about the operational amplifier being of a transconductance type, but Gaalema teaches an operational amplifier being of a transconductance ( see para. [0099] ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the low frequency amplifier disclosed in the phase range finder disclosed in Hu with the transconductance operational amplifier taught in Gaalema with a reasonable expectation of success because it provides distinct advantages like electrically tunable gain, high-speed operation, and excellent linear voltage-to-current conversion. Regarding Claim 19 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ) wherein the a wavelength of the first invisible light signal is equal to a wavelength of the second invisible light signal ( Hu, para. [0065]: "the light emitting module emits a laser beam modulated by a high-frequency modulation signal as a detection optical signal and a reference optical signal, respectively, wherein the optical signal is reflected by the target object to form an echo signal related to the distance of the target object" , wherein para. [0057]: "the laser emitting unit 20 comprises a laser diode, such as a low-power continuous laser diode in the infrared band" ) , and the wavelength of the first invisible light signal is larger than a wavelength of the visible light signal ( Hu discloses emitting invisible IR light as cited above, which has a wavelength higher than that of visible light ) . Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over modified Hu et al. (US 2021/0247495) in view of Herman et al. (US 2020/0232895). Regarding Claim 20 , as best understood, modified Hu discloses a dual-wavelength phase range finder ( para. [0041]: "laser radar system", see fig. 1 ), with visible light signal ( Dunne, para. [0025] ). Modified Hu is silent about the color of the visible light signal is green, blue, or red., but Herman teaches an optical sensor with color of the visible light signal is green, blue, or red ( para. [0035], “…The optical sensor 28 may detect one or more wavelengths, such as red, blue, green, visible light, near infrared, ultraviolet, etc….” ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the visible light signal in the phase range finder disclosed in modified Hu with the green, blue or red visible light signals taught in Herman with a reasonable expectation of success because green is best for high daytime visibility, red is ideal for low-light/short-range and power efficiency, and blue is excellent for precision on dark surfaces. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to FILLIN "Examiner name" \* MERGEFORMAT ASSRES H WOLDEMARYAM whose telephone number is FILLIN "Phone number" \* MERGEFORMAT (571)272-6607 . The examiner can normally be reached FILLIN "Work Schedule?" \* MERGEFORMAT Monday-Friday 8AM-5PM . Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, FILLIN "SPE Name?" \* MERGEFORMAT Joshua Huson can be reached at FILLIN "SPE Phone?" \* MERGEFORMAT 571-270-5301 . The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. FILLIN "Examiner Stamp" \* MERGEFORMAT Assres H. Woldemaryam Primary Examiner (Aeronautics and Astronautics) Art Unit 3642 /ASSRES H WOLDEMARYAM/ Primary Examiner, Art Unit 3642