# US 9,518,854 B2 · Resonance circuit used for measurement device and measurement device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,854 B2 - Document ID: US9518854B2 - Status: Granted - Kind: B2 - Application number: 15/015,262 - Filed: 2016-02-04 - Published: 2016-08-11 - Granted: 2016-12-13 - Earliest claimed: 2015-02-05 - Assignees: Yokogawa Electric Corporation - Applicants: Yokogawa Electric Corporation - Inventors: Yuki Ikadai; Masami Wada - Web page: https://patentgrep.com/patent/US9518854B2 ## CPC - G01F 1/8422: {exciters} - G01F 1/8436: {signal processing} - G06G 7/16: for multiplication or division {(G06G7/19 and G06G7/24 take precedence; measuring electric power G01R21/00)} - H03K 5/02: by amplifying (H03K5/04 takes precedence) - H03M 3/30: {Delta-sigma modulation} - G01F 1/8431: {electronic circuits} - G01N 9/002: {using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis (G01N9/34 takes precedence)} - G01N 2009/006: {vibrating tube, tuning fork} - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - G06G: ANALOGUE COMPUTERS (analogue optical computing devices G06E3/00) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A resonance circuit is configured to receive a pulse density signal obtained by ΔΣ-modulating an analog displacement signal by a ΔΣ modulator and a multi-bit signal obtained from the pulse density signal and to generate an excitation signal based on the pulse density signal and the multi-bit signal. The resonance circuit includes an amplification factor controller configured to set an amplification factor depending on a vibration signal obtained from the multi-bit signal, a multiplier configured to amplify a level of the pulse density signal by the amplification factor, and a circuit group configured to generate the excitation signal based on a pulse density signal obtained by further ΔΣ-modulating an output of the multiplier. The amplification factor controller is configured to set the amplification factor using a proportional control and an integral control based a difference between an amplitude signal obtained from the vibration signal and a target amplitude value. ## Claims ### Claim 1 A resonance circuit used for a measurement device, configured to receive a pulse density signal obtained by ΔΣ-modulating an analog displacement signal by a ΔΣ modulator and a multi-bit signal obtained from the pulse density signal and to generate an excitation signal based on the pulse density signal and the multi-bit signal, the resonance circuit comprising: an amplification factor controller configured to set an amplification factor depending on a vibration signal obtained from the multi-bit signal; a multiplier configured to amplify a level of the pulse density signal by the amplification factor; and a circuit group configured to generate the excitation signal based on a pulse density signal obtained by further ΔΣ-modulating an output of the multiplier; wherein the amplification factor controller is configured to set the amplification factor using a proportional control and an integral control based a difference between an amplitude signal obtained from the vibration signal and a target amplitude value. ### Claim 2 (depends on 1) The resonance circuit according to claim 1, wherein for the integral control, the amplification factor controller has a limit value to an integrated value. ### Claim 3 (depends on 1) The resonance circuit according to claim 1, wherein for the integral control, the amplification factor controller is configured to set an integrated value to 0 if the amplitude signal exceeds a reference value. ### Claim 4 (depends on 2) The resonance circuit according to claim 2, wherein the amplification factor controller is configured so that if the integrated value is negative, the integrated value is limited to 0. ### Claim 5 (depends on 1) The resonance circuit according to claim 1, wherein the amplification factor controller comprises an amplifier and an integrator, the amplifier configured to amplify the difference between the amplitude signal obtained from the vibration signal and the target amplitude value, the integrator configured to integrate a value outputted from the amplifier. ### Claim 6 (depends on 5) The resonance circuit according to claim 5, wherein the amplification factor controller further comprises another amplifier and an adder, the another amplifier configured to amplify the difference between the amplitude signal obtained from the vibration signal and the target amplitude value, the adder configured to add a value of the proportional control outputted by the another amplifier and a value of the integral control outputted by the integrator. ### Claim 7 A measurement device comprising: a detector configured to output an analog displacement signal based on displacement of an object occurred when the object is vibrated; a ΔΣ modulator configured to ΔΣ-modulate the analog displacement signal to output a pulse density signal; a low-pass filter configured to convert the pulse density signal to a multi-bit signal; and a resonance circuit configured to generate an excitation signal based on the pulse density signal and the multi-bit signal, the resonance circuit comprising: an amplification factor controller configured to set an amplification factor depending on a vibration signal obtained from the multi-bit signal; a multiplier configured to amplify a level of the pulse density signal by the amplification factor; and a circuit group configured to generate the excitation signal based on a pulse density signal obtained by further ΔΣ-modulating an output of the multiplier; wherein the amplification factor controller is configured to set the amplification factor using a proportional control and an integral control based a difference between an amplitude signal obtained from the vibration signal and a target amplitude value.