TWI823704B - Signal measurement method and doppler ultrasonic system - Google Patents
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本揭露是有關於一種訊號量測方法與都卜勒超音波系統，特別是一種分離正逆流訊號的訊號量測方法與都卜勒超音波系統。The present disclosure relates to a signal measurement method and a Doppler ultrasound system, in particular to a signal measurement method and a Doppler ultrasound system for separating forward and reverse flow signals.
以都卜勒超音波系統量測血液流速時，血液的流動方向可分為遠離(以下稱正流)與接近(以下稱逆流)超音波發射源兩種。血液流速方向遠離(正流)時，其反射超音波頻率比發射的頻率低，反之，血液流速方向為接近(逆流)時，則反射頻率較高。由於超音波訊號頻率高取樣不易，故使用混波器以發射頻率為載波進行降頻再取樣。然而，混波器輸出訊號頻譜無法直接判斷輸入訊號頻率是大於或小於載波頻率，需用額外的方式來判斷。When measuring blood flow velocity with a Doppler ultrasound system, the blood flow direction can be divided into two types: away from (hereinafter referred to as forward flow) and close to (hereinafter referred to as counterflow) the ultrasonic emission source. When the blood flow velocity direction is away from (forward flow), the reflected ultrasonic frequency is lower than the transmitted frequency. On the contrary, when the blood flow velocity direction is close to (countercurrent flow), the reflected ultrasonic frequency is higher. Since ultrasonic signals have high frequencies and are difficult to sample, a mixer is used to down-convert and re-sample the transmitted frequency as the carrier. However, the mixer output signal spectrum cannot directly determine whether the input signal frequency is greater than or less than the carrier frequency, and additional methods are required to determine.
目前常用的方法有：帶濾波法、平移載波解調法、同相/正交解調法。然而，上述方法須使用龐大的電路且取樣率較高，皆不適合使用在基於藍芽傳輸的攜帶式電子產品。攜帶式電子產品的硬體規格受到尺寸小、驅動電壓小、要求耗電量小等限制，無法使用龐大的電路。而以藍芽傳輸即時資訊的裝置，因受到藍芽傳輸吞吐量的限制，過高的取樣率會發生掉資料使訊號失真。Currently commonly used methods include: band filtering method, shifting carrier demodulation method, in-phase/quadrature demodulation method. However, the above method requires the use of bulky circuits and a high sampling rate, and is not suitable for use in portable electronic products based on Bluetooth transmission. The hardware specifications of portable electronic products are limited by small size, low driving voltage, low power consumption, etc., and they cannot use huge circuits. For devices that use Bluetooth to transmit real-time information, due to limitations in Bluetooth transmission throughput, an excessively high sampling rate will cause data loss and signal distortion.
故，一種在可選擇正逆流訊號的同時又可應用在攜帶式電子產品的訊號量測方法與都卜勒超音波系統被提出，以解決上述問題。Therefore, a signal measurement method and Doppler ultrasonic system that can select both forward and reverse current signals and can be applied to portable electronic products are proposed to solve the above problems.
本揭示之一些實施方式是關於一種訊號量測方法，適用於都卜勒超音波系統。訊號量測包含以下步驟：依據預設流向切換第一載波頻率；由第一級混波器依據第一載波頻率頻移輸入訊號，以將輸入訊號中的目標訊號移至低頻，並產生第一頻移訊號；由第一級濾波器濾除第一頻移訊號的高頻部分，以產生第一低頻訊號，其中第一低頻訊號包含目標訊號；由第二級混波器以及第二級濾波器去除第一低頻訊號中的雜訊，以產生第二低頻訊號；以及將第二低頻訊號輸入至數位訊號處理器，以分析輸入訊號的目標訊號的流速。Some embodiments of the present disclosure relate to a signal measurement method suitable for Doppler ultrasound systems. Signal measurement includes the following steps: switching the first carrier frequency according to the preset flow direction; frequency-shifting the input signal according to the first carrier frequency by the first-stage mixer to move the target signal in the input signal to a low frequency and generating the first Frequency shift signal; the first-stage filter filters out the high-frequency part of the first frequency-shift signal to generate a first low-frequency signal, where the first low-frequency signal contains the target signal; the second-stage mixer and the second-stage filter The device removes noise in the first low-frequency signal to generate a second low-frequency signal; and inputs the second low-frequency signal to a digital signal processor to analyze the flow rate of a target signal of the input signal.
本揭示之一些實施方式是關於一種都卜勒超音波系統，包含類比訊號處理器和數位訊號處理器。類比訊號處理器包含第一級混波器、第一級濾波器、第二級混波器以及第二級濾波器。第一級混波器用以依據第一載波頻率頻移輸入訊號，以將輸入訊號中的目標訊號移至低頻，並產生第一頻移訊號。第一載波頻率係依據預設流向切換。第一級濾波器耦接於第一級混波器，用以濾除第一頻移訊號的高頻部分，以產生第一低頻訊號，其中第一低頻訊號包含目標訊號。第二級混波器以及第二級濾波器耦接於第一級濾波器，用以去除第一低頻訊號中的雜訊，以產生第二低頻訊號。數位訊號處理器耦接於類比訊號處理器，用以依據第二低頻訊號分析輸入訊號的目標訊號的流速。Some embodiments of the present disclosure relate to a Doppler ultrasound system, including an analog signal processor and a digital signal processor. The analog signal processor includes a first-stage mixer, a first-stage filter, a second-stage mixer and a second-stage filter. The first-stage mixer is used to frequency-shift the input signal according to the first carrier frequency to move the target signal in the input signal to a low frequency and generate a first frequency-shifted signal. The first carrier frequency is switched according to the preset flow direction. The first-stage filter is coupled to the first-stage mixer and used to filter out the high-frequency part of the first frequency-shifted signal to generate a first low-frequency signal, where the first low-frequency signal includes the target signal. The second-stage mixer and the second-stage filter are coupled to the first-stage filter and used to remove noise in the first low-frequency signal to generate a second low-frequency signal. The digital signal processor is coupled to the analog signal processor and used to analyze the flow rate of the target signal of the input signal based on the second low-frequency signal.
為讓本發明的上述特徵和優點能更明顯易懂，下文特舉實施例，並配合所附圖式作詳細說明如下。In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings.
在本文中所使用的用詞『耦接』亦可指『電性耦接』，且用詞『連接』亦可指『電性連接』。『耦接』及『連接』亦可指二個或多個元件相互配合或相互互動。The term "coupling" used in this article may also refer to "electrical coupling", and the term "connection" may also refer to "electrical connection". "Coupling" and "connection" can also refer to the cooperation or interaction of two or more components with each other.
請參閱第1圖。第1圖為根據本發明一些實施例所繪示的都卜勒超音波系統100的示意圖。See picture 1. Figure 1 is a schematic diagram of a Doppler
如第1圖所繪示，都卜勒超音波系統100包含類比訊號處理器110和數位訊號處理器130。數位訊號處理器130耦接於類比訊號處理器110。As shown in FIG. 1 , the Doppler
如第1圖所繪示，類比訊號處理器110包含第一級混波器112、第一級濾波器114、第二級混波器116和第二級濾波器118。在連接關係上，第一級混波器112和第一級濾波器114相耦接，第一級濾波器114和第二級混波器116相耦接，而第二級混波器116和第二級濾波器118相耦接。As shown in FIG. 1 , the analog signal processor 110 includes a first-stage mixer 112 , a first-stage filter 114 , a second-
於部分實施例中，類比訊號處理器110更包含載波頻率切換電路119。載波頻率切換電路119耦接於第一級混波器112。In some embodiments, the analog signal processor 110 further includes a carrier
於部分實施例中，都卜勒超音波系統100更包含超音波接收器150，耦接於類比訊號處理器110，並用以接收超音波訊號。In some embodiments, the Doppler
於部分實施例中，都卜勒超音波系統100更包含類比數位轉換器170，耦接於類比訊號處理器110與數位訊號處理器130之間，用以將類比訊號轉換為數位訊號。In some embodiments, the Doppler
於部分實施例中，都卜勒超音波系統100更包含顯示與操作介面190，耦接於類比訊號處理器110與數位訊號處理器130。In some embodiments, the Doppler
請參閱第2圖。第2圖為根據本發明一些實施例所繪示的訊號量測方法200的流程圖。訊號量測方法200可由第1圖中的都卜勒超音波系統100執行。訊號量測方法200包含步驟S210至S290。See picture 2. Figure 2 is a flow chart of a
在步驟S210中，依據預設流向切換第一載波頻率。請一併參閱第1圖。於部分實施例中，步驟S210係由載波頻率切換電路119執行。In step S210, the first carrier frequency is switched according to the preset flow direction. Please also refer to Figure 1. In some embodiments, step S210 is performed by the carrier
於部分實施例中，當預設流向為正流時，第一載波頻率為超音波發射頻率減去最大變化頻率。另一方面，當預設流向為逆流時，第一載波頻率為超音波發射頻率加上最大變化頻率。於部分實施例中，最大變化頻率係為人體最高血液流速反射的都卜勒超音波相對於超音波發射頻率的最大頻率變化。In some embodiments, when the preset flow direction is forward flow, the first carrier frequency is the ultrasonic transmission frequency minus the maximum change frequency. On the other hand, when the preset flow direction is counterflow, the first carrier frequency is the ultrasonic transmission frequency plus the maximum change frequency. In some embodiments, the maximum change frequency is the maximum frequency change of the Doppler ultrasound reflected by the highest blood flow rate of the human body relative to the ultrasound emission frequency.
舉例而言，假設超音波發射頻率係為頻率Wc，最大變化頻率係為頻率Wm。當最大變化頻率接收到的預設流向係為正流時，載波頻率切換電路119將第一載波頻率切換為頻率Wc-Wm。另一方面，當最大變化頻率接收到的預設流向係為逆流時，載波頻率切換電路119將第一載波頻率切換為頻率Wc+Wm。For example, assume that the ultrasonic emission frequency is frequency Wc and the maximum change frequency is frequency Wm. When the preset flow direction received by the maximum change frequency is forward flow, the carrier
於步驟S230中，由第一級混波器依據第一載波頻率頻移輸入訊號，以將輸入訊號中的目標訊號移至低頻，並產生第一頻移訊號。於部分實施例中，步驟S230係由第1圖中的第一級混波器112執行。In step S230, the first-stage mixer frequency-shifts the input signal according to the first carrier frequency to move the target signal in the input signal to a low frequency and generates a first frequency-shifted signal. In some embodiments, step S230 is performed by the first-stage mixer 112 in FIG. 1 .
當預設流向為正流時，正流訊號即為目標訊號。而當預設流向為逆流時，逆流訊號即為目標訊號。When the default flow direction is forward flow, the forward flow signal is the target signal. When the default flow direction is countercurrent, the countercurrent signal is the target signal.
於部分實施例中，在步驟S230，當預設流向為正流時，第一級混波器112依據第一載波頻率將輸入訊號S0中的正流訊號移至低頻，並將輸入訊號S0中的逆流訊號移至高頻，以產生頻移訊號S1。另一方面，當預設流向為逆流時，第一級混波器112依據第一載波頻率將輸入訊號S0中的逆流訊號移至低頻，並將輸入訊號S0中的正流訊號移至高頻以產生頻移訊號S1。In some embodiments, in step S230, when the default flow direction is forward flow, the first stage mixer 112 moves the forward flow signal in the input signal S0 to a low frequency according to the first carrier frequency, and mixes the forward flow signal in the input signal S0 The countercurrent signal is shifted to a high frequency to generate a frequency shift signal S1. On the other hand, when the default flow direction is reverse flow, the first-stage mixer 112 moves the reverse flow signal in the input signal S0 to a low frequency according to the first carrier frequency, and moves the forward flow signal in the input signal S0 to a high frequency. to generate the frequency shift signal S1.
舉例而言，於部分實施例中，在步驟S230，當預設流向為正流時，第一級混波器112依據載波頻率Wc-Wm將輸入訊號S0中的正流訊號移至低頻，並將輸入訊號S0中的逆流訊號移至高頻。另一方面，當預設流向為逆流時，第一級混波器112依據載波頻率Wc+Wm將輸入訊號S0中的逆流訊號移至低頻，並將輸入訊號S0中的正流訊號移至高頻。For example, in some embodiments, in step S230, when the default flow direction is forward flow, the first-stage mixer 112 moves the forward flow signal in the input signal S0 to a low frequency according to the carrier frequency Wc-Wm, and Move the countercurrent signal in the input signal S0 to high frequency. On the other hand, when the default flow direction is reverse flow, the first stage mixer 112 moves the reverse flow signal in the input signal S0 to a low frequency according to the carrier frequency Wc+Wm, and moves the forward flow signal in the input signal S0 to a high frequency. Frequency.
請一併參閱第3圖。第3圖為根據本發明一些實施例所繪示的輸入訊號S0的示意圖。如第3圖所繪示，超音波發射頻率係為頻率Wc。在超音波發射頻率Wc的左邊包含遠離探頭的正流訊號，而在超音波發射頻率Wc的右邊包含流向探頭的逆流訊號。Please also refer to Figure 3. Figure 3 is a schematic diagram of the input signal S0 according to some embodiments of the present invention. As shown in Figure 3, the ultrasonic emission frequency is frequency Wc. The left side of the ultrasonic transmitting frequency Wc contains forward flow signals away from the probe, while the right side of the ultrasonic transmitting frequency Wc contains countercurrent signals flowing toward the probe.
請一併參閱第4圖。第4圖為根據本發明一些實施例所繪示的第1圖中的頻移訊號S1的其中一種實施例S1A的示意圖。如第4圖所繪示的頻移訊號S1A係為預設流向為正流時，第一級混波器112依據載波頻率Wc-Wm將第3圖中的輸入訊號S0進行頻移所產生的頻移訊號S1A。Please also refer to Figure 4. FIG. 4 is a schematic diagram of one embodiment S1A of the frequency shift signal S1 in FIG. 1 according to some embodiments of the present invention. As shown in Figure 4, the frequency shift signal S1A is generated by the first stage mixer 112 frequency shifting the input signal S0 in Figure 3 according to the carrier frequency Wc-Wm when the default flow direction is forward flow. Frequency shift signal S1A.
如第4圖所繪示，在頻移訊號S1A中，以頻率Wm為中心，在頻率Wm的左邊包含遠離探頭的正流訊號，而在頻率Wm的右邊包含流向探頭的逆流訊號。需注意的是，在頻移訊號S1A中，更包含以頻率2Wc-Wm為中心的正流訊號與逆流訊號。由於以頻率2Wc-Wm為中心的正流訊號與逆流訊號將在後續步驟中被濾除，在此不繪示。As shown in Figure 4, in the frequency shift signal S1A, with the frequency Wm as the center, the left side of the frequency Wm includes a forward signal away from the probe, and the right side of the frequency Wm includes a countercurrent signal flowing toward the probe. It should be noted that the frequency shift signal S1A also includes a forward signal and a reverse signal centered at the frequency 2Wc-Wm. Since the forward and reverse flow signals centered at frequency 2Wc-Wm will be filtered out in subsequent steps, they are not shown here.
請一併參閱第5圖。第5圖為根據本發明一些實施例所繪示的第1圖中的頻移訊號S1的另一種實施例S1B的示意圖。如第5圖所繪示的頻移訊號S1B係為預設流向為逆流時，第一級混波器112依據載波頻率Wc+Wm將第3圖中的輸入訊號S0進行頻移所產生的頻移訊號S1B。Please also refer to Figure 5. FIG. 5 is a schematic diagram of another embodiment S1B of the frequency shift signal S1 in FIG. 1 according to some embodiments of the present invention. As shown in Figure 5, the frequency shift signal S1B is the frequency generated by the first stage mixer 112 frequency shifting the input signal S0 in Figure 3 according to the carrier frequency Wc+Wm when the default flow direction is countercurrent. Shift signal S1B.
如第5圖所繪示，在頻移訊號S1B中，以頻率-Wm為中心，在頻率-Wm的左邊包含遠離探頭的正流訊號，而在頻率-Wm的右邊包含流向探頭的逆流訊號。由於頻移後產生的訊號包含負頻率的訊號，負頻率的訊號再經由以0Hz的頻率為基準映射到正頻率，以量測工具即可量測到如第5圖的方框處的頻譜。即，以以頻率Wm為中心，在頻率Wm的右邊包含遠離探頭的正流訊號，而在頻率Wm的左邊包含流向探頭的逆流訊號。As shown in Figure 5, in the frequency shift signal S1B, with the frequency -Wm as the center, the left side of the frequency -Wm contains the forward signal flowing away from the probe, and the right side of the frequency -Wm contains the countercurrent signal flowing towards the probe. Since the signal generated after frequency shift includes a negative frequency signal, the negative frequency signal is mapped to a positive frequency based on the frequency of 0 Hz, and the spectrum at the box in Figure 5 can be measured with a measurement tool. That is, with the frequency Wm as the center, the right side of the frequency Wm includes the forward flow signal away from the probe, and the left side of the frequency Wm includes the reverse flow signal flowing toward the probe.
需注意的是，在頻移訊號S1B中，更包含以頻率2Wc+Wm為中心的正流訊號與逆流訊號。由於以頻率2Wc+Wm為中心的正流訊號與逆流訊號將在後續步驟中被濾除，在此不繪示。It should be noted that the frequency shift signal S1B also includes a forward signal and a reverse signal centered at the frequency 2Wc+Wm. Since the forward and reverse flow signals centered at frequency 2Wc+Wm will be filtered out in subsequent steps, they are not shown here.
請回頭參閱第2圖。在步驟S250中，由第一級濾波器濾除第一頻移訊號的高頻部分，以產生第一低頻訊號。第一低頻訊號包含目標訊號。請一併參閱第1圖。於部分實施例中，步驟S250係由第1圖中的第一級濾波器114所執行。於部分實施例中，第一級濾波器114係為低通濾波器。第一級濾波器114濾除頻移訊號S1中的高頻部分，以產生低頻訊號S2。Please refer back to Figure 2. In step S250, the high-frequency part of the first frequency-shifted signal is filtered out by the first-stage filter to generate a first low-frequency signal. The first low frequency signal contains the target signal. Please also refer to Figure 1. In some embodiments, step S250 is performed by the first-stage filter 114 in FIG. 1 . In some embodiments, the first-stage filter 114 is a low-pass filter. The first-stage filter 114 filters out the high-frequency part of the frequency-shifted signal S1 to generate a low-frequency signal S2.
於部分實施例中，第一級濾波器114的截止頻率為最大變化頻率Wm。In some embodiments, the cutoff frequency of the first-stage filter 114 is the maximum change frequency Wm.
請一併參閱第6圖。第6圖為根據本發明一些實施例所繪示的第1圖中的低頻訊號S2的其中一種實施例S2A的示意圖。第6圖中的低頻訊號S2A係依據第4圖中的頻移訊號S1A所產生的低頻訊號。Please also refer to Figure 6. FIG. 6 is a schematic diagram of one embodiment S2A of the low-frequency signal S2 in FIG. 1 according to some embodiments of the present invention. The low-frequency signal S2A in Figure 6 is a low-frequency signal generated based on the frequency shift signal S1A in Figure 4.
請一併參閱第4圖和第6圖。於部分實施例中，第1圖中的第一級濾波器114將4圖中的頻移訊號S1A中大於頻率Wm的高頻部分濾除後，所產生的低頻訊號S2A如第6圖所繪示，僅剩下低於頻率Wm的低頻部分。低於頻率Wm的低頻部分係為遠離探頭的正流訊號，即為預設流向為正流時的目標訊號。Please refer to Figure 4 and Figure 6 together. In some embodiments, after the first-stage filter 114 in Figure 1 filters out the high-frequency part greater than the frequency Wm in the frequency shift signal S1A in Figure 4, the generated low-frequency signal S2A is as shown in Figure 6 shows that only the low frequency part below the frequency Wm remains. The low-frequency part below the frequency Wm is the forward flow signal away from the probe, which is the target signal when the default flow direction is forward flow.
請一併參閱第7圖。第7圖為根據本發明一些實施例所繪示的第1圖中的低頻訊號S2的另一種實施例S2B的示意圖。第7圖中的低頻訊號S2B係依據第5圖中的頻移訊號S1B所產生的低頻訊號。Please also refer to Figure 7. FIG. 7 is a schematic diagram of another embodiment S2B of the low-frequency signal S2 in FIG. 1 according to some embodiments of the present invention. The low-frequency signal S2B in Figure 7 is a low-frequency signal generated based on the frequency shift signal S1B in Figure 5.
請一併參閱第5圖和第7圖。於部分實施例中，第1圖中的第一級濾波器114將5圖中的頻移訊號S1B中大於頻率Wm的高頻部分濾除後，所產生的低頻訊號S2B如第6圖所繪示，僅剩下低於頻率Wm的低頻部分。低於頻率Wm的低頻部分係為流向探頭的逆流訊號，即為預設流向為逆流時的目標訊號。Please refer to Figure 5 and Figure 7 together. In some embodiments, after the first-stage filter 114 in Figure 1 filters out the high-frequency part greater than the frequency Wm in the frequency shift signal S1B in Figure 5, the generated low-frequency signal S2B is as shown in Figure 6 shows that only the low frequency part below the frequency Wm remains. The low-frequency part below the frequency Wm is the counterflow signal flowing to the probe, which is the target signal when the default flow direction is counterflow.
如此，透過如上所述步驟S210至步驟S250的操作，依據預設流向切換混波器的載波頻率，再透過低通濾波器將高頻部分濾除，可有效地將逆流訊號與正流訊號分開，僅保留目標訊號。In this way, through the above-mentioned operations from step S210 to step S250, the carrier frequency of the mixer is switched according to the preset flow direction, and then the high-frequency part is filtered through the low-pass filter, so that the reverse flow signal and the forward flow signal can be effectively separated. , only the target signal is retained.
於部分實施例中，在正流訊號和逆流訊號之間的交界頻寬處包含環境的低頻訊號，這些低頻訊號的強度大多比超音波訊號牆上許多。舉例而言，在以超音波測量血管流速時，會有來自肌肉或血管壁脈動等低頻振動訊號。這些訊號的強度比血流訊號強數百倍。因此，第一級濾波器114設計為高階低通濾波器，以濾掉正流訊號和逆流訊號之間的交界頻寬處的低頻訊號。如上所述的低頻訊號係為0至200Hz的非流速訊號。In some embodiments, the interface bandwidth between the forward signal and the reverse signal includes ambient low-frequency signals, and the intensity of these low-frequency signals is mostly much greater than that of the ultrasonic signal wall. For example, when measuring blood vessel flow velocity using ultrasound, there will be low-frequency vibration signals such as muscle or blood vessel wall pulsations. These signals are hundreds of times stronger than blood flow signals. Therefore, the first-stage filter 114 is designed as a high-order low-pass filter to filter out low-frequency signals at the interface bandwidth between the forward signal and the reverse signal. The low-frequency signal mentioned above is a non-flow signal from 0 to 200Hz.
於部分實施例中，第一級濾波器114設計為12階以上的高階低通濾波器。In some embodiments, the first-stage filter 114 is designed as a high-order low-pass filter of order 12 or above.
於部分實施例中，由於0至200Hz的非流速訊號係為較強的訊號，需透過第一級濾波器114將非流速訊號衰減10倍(約-20dB)，才不會蓋過待測的超音波的訊號。In some embodiments, since the non-flow velocity signal from 0 to 200 Hz is a relatively strong signal, the non-flow velocity signal needs to be attenuated by 10 times (approximately -20dB) through the first-stage filter 114 so as not to overwhelm the signal to be measured. Ultrasonic signal.
請回頭參閱第2圖。於步驟S270中，由第二級混波器以及第二級濾波器去除第一低頻訊號中的雜訊，以產生第二低頻訊號。請一併參閱第1圖，於部分實施例中，步驟S270係由第二級混波器116和第二級濾波器118執行。Please refer back to Figure 2. In step S270, the second-stage mixer and the second-stage filter remove noise from the first low-frequency signal to generate a second low-frequency signal. Please also refer to FIG. 1 . In some embodiments, step S270 is performed by the second-
於部分實施例中，第二級混波器116的第二載波頻率為最大變化頻率Wm。In some embodiments, the second carrier frequency of the second-
請一併參閱第3圖。以超音波發射頻率Wc為中心，訊號頻率比超音波發射頻率Wc快越多代表流向探頭的速度越快，而訊號頻率比超音波發射頻率Wc慢越多代表遠離探頭的速度越快。在第一級混波器112對輸入訊號S0進行移頻(降頻)操作之後，在第3圖的輸入訊號S0中原本流速為0時的頻率(即為頻率Wc)，在第4圖的頻移訊號S1A和第5圖的頻移訊號S1B中尉變成頻率Wm。在第一級濾波器114濾除頻率Wm以上的訊號之後，在第6圖的低頻訊號S2A和第7圖的低頻訊號S2B中，頻率越低，流向探頭或遠離探頭的速度越快。Please also refer to Figure 3. Taking the ultrasonic transmission frequency Wc as the center, the faster the signal frequency is than the ultrasonic transmission frequency Wc, the faster the flow to the probe, and the slower the signal frequency is than the ultrasonic transmission frequency Wc, the faster the flow away from the probe. After the first-stage mixer 112 performs a frequency shifting (down-frequency) operation on the input signal S0, the frequency when the original flow rate is 0 (that is, the frequency Wc) in the input signal S0 in Figure 3 is in Figure 4 The frequency-shifted signal S1A and the frequency-shifted signal S1B in FIG. 5 become frequency Wm. After the first-stage filter 114 filters out signals above the frequency Wm, in the low-frequency signal S2A in Figure 6 and the low-frequency signal S2B in Figure 7, the lower the frequency, the faster it flows toward or away from the probe.
經過第1圖中的第二級混波器116依據載波頻率Wm頻移第一低頻訊號S2之後，經過降頻處理，在產生的第二頻移訊號S3中，頻率為0時的流速為0，而頻率越高時流速越高。此操作可降低類比數位轉換器170的取樣率，並可完整將訊號取樣。After the second-
接著，第1圖中的第二級濾波器118將第二頻移訊號S3中的環境高頻雜訊(如數位訊號諧波、第二級混波器高頻諧波等雜訊)濾除，以產生第二低頻訊號S4。Next, the second-
請回頭參閱第2圖。在步驟S290中，將第二低頻訊號輸入至數位訊號處理器，以分析輸入訊號的目標訊號的流速。於部分實施例中，在步驟S290中，類比數位轉換器170接收第二低頻訊號S4後，產生數位訊號S5並傳送至數位訊號處理器130以進行數位訊號處理分析與計算。Please refer back to Figure 2. In step S290, the second low-frequency signal is input to the digital signal processor to analyze the flow rate of the target signal of the input signal. In some embodiments, in step S290, after receiving the second low-frequency signal S4, the analog-to-
於部分實施例中，數位訊號處理器130包含都卜勒訊號頻域分析電路132與流速計算電路134。都卜勒訊號頻域分析電路132與流速計算電路134相耦接。都卜勒訊號頻域分析電路132分析數位訊號S5，並由流速計算電路134計算流速。In some embodiments, the
於部分實施例中，在計算出流速後，數位訊號處理器130將計算出的目標訊號的流速傳送至顯示與操作介面190，以將流速顯示於顯示與操作介面190上供使用者查看。此外，使用者亦可透過顯示與操作介面190選擇預設流向。於部分實施例中，在使用者選擇預設流向之後，顯示與操作介面190更將預設流向傳送至載波頻率切換電路119，載波頻率切換電路119再依據預設流向切換第一級混波器112的載波頻率。In some embodiments, after calculating the flow rate, the
由於在第一低頻訊號S2中僅剩下與預設流向相對應的目標訊號，因此在步驟S290中計算出的流速即為目標訊號的流速。Since only the target signal corresponding to the preset flow direction remains in the first low-frequency signal S2, the flow rate calculated in step S290 is the flow rate of the target signal.
透過上述實施例的步驟，於本案的實施例中，提供一種訊號量測方法與都卜勒超音波系統，透過預設流向的設定切換載波頻率，並由第一級混波器依據切換後的載波頻率進行移頻，再由第一級濾波器將移頻訊號中的高頻部分濾除，可僅保留目標訊號，以達到分離訊號的需求。此外，透過第二級混波器和第二級濾波器，將分離好的都卜勒訊號進行頻移(降頻)，以將都卜勒訊號的頻率範圍降低。如此，可降低後續類比數位轉換器轉換頻率的需求，並進而降低資料量。因此，本案的實施方式在可選擇正逆流訊號的同時又可應用在攜帶式電子產品中。Through the steps of the above embodiment, in the embodiment of this case, a signal measurement method and a Doppler ultrasound system are provided. The carrier frequency is switched through the setting of the default flow direction, and the first stage mixer is based on the switched The carrier frequency is frequency-shifted, and then the high-frequency part of the frequency-shifted signal is filtered out by the first-stage filter, leaving only the target signal to meet the signal separation requirements. In addition, through the second-stage mixer and the second-stage filter, the separated Doppler signal is frequency shifted (down-frequency) to reduce the frequency range of the Doppler signal. In this way, the need for conversion frequency of subsequent analog-to-digital converters can be reduced, thereby reducing the amount of data. Therefore, the implementation of this case can select forward and reverse signals and at the same time be applied to portable electronic products.
於部分實施例中，類比訊號處理器110可為但不限於具有類比訊號處理功能或類似功能的處理器、電路或元件。於部分實施例中，數位訊號處理器130可為但不限於具有數位訊號處理功能或類似功能的處理器、電路或元件。於部分實施例中，超音波接收器150可為但不限於具有超音波訊號接收功能或類似功能的處理器、電路或元件。於部分實施例中，類比數位轉換器170可為但不限於具有類比訊號轉數位訊號功能或類似功能的處理器、電路或元件。於部分實施例中，顯示與操作介面190可為但不限於具有顯示訊號、接收訊息與傳送訊息或類似功能的處理器、電路或元件。In some embodiments, the analog signal processor 110 may be, but is not limited to, a processor, circuit or component with analog signal processing functions or similar functions. In some embodiments, the
各種功能性元件已於此公開。對於本技術領域具通常知識者而言，功能性元件可由電路(不論是專用電路，或是於一或多個處理器及編碼指令控制下操作的通用電路)實現。Various functional elements are disclosed herein. It will be apparent to one of ordinary skill in the art that functional elements may be implemented by circuitry, whether dedicated circuitry or general purpose circuitry operating under the control of one or more processors and coded instructions.
雖然本揭示已以實施方式揭露如上，然其並非用以限定本揭示，任何本領域具通常知識者，在不脫離本揭示之精神和範圍內，當可作各種之更動與潤飾，因此本揭示之保護範圍當視後附之申請專利範圍所界定者為準。Although the disclosure has been disclosed in the above embodiments, it is not intended to limit the disclosure. Anyone with ordinary knowledge in the art can make various modifications and modifications without departing from the spirit and scope of the disclosure. Therefore, the disclosure The scope of protection shall be subject to the scope of the patent application attached.
100:都卜勒超音波系統 110:類比訊號處理器 130:數位訊號處理器 150:超音波接收器 170:類比數位轉換器 190:顯示與操作介面 112:第一級混波器 114:第一級濾波器 116:第二級混波器 118:第二級濾波器 119:載波頻率切換電路 132:都卜勒訊號頻域分析電路 134:流速計算電路 200:訊號量測方法 S210,S230,S250,S270,S290:步驟 S0:輸入訊號 S1:頻移訊號 S2:低頻訊號 S3:頻移訊號 S4:低頻訊號 S5:數位訊號 A:振幅 f:頻率 Wc:頻率 Wm:頻率 S1A,S1B:頻移訊號 S2A,S2B:低頻訊號100: Doppler ultrasound system 110: Analog signal processor 130:Digital signal processor 150: Ultrasonic receiver 170:Analog-to-digital converter 190: Display and operation interface 112: First stage mixer 114: First stage filter 116: Second stage mixer 118: Second stage filter 119:Carrier frequency switching circuit 132: Doppler signal frequency domain analysis circuit 134: Flow velocity calculation circuit 200: Signal measurement method S210, S230, S250, S270, S290: steps S0: input signal S1: Frequency shift signal S2: low frequency signal S3: Frequency shift signal S4: low frequency signal S5: digital signal A: Amplitude f: frequency Wc: frequency Wm: frequency S1A, S1B: frequency shift signal S2A, S2B: low frequency signal
為讓本揭示之上述和其他目的、特徵、優點與實施例能夠更明顯易懂，所附圖式之說明如下： 第1圖為根據本發明一些實施例所繪示的都卜勒超音波系統的示意圖； 第2圖為根據本發明一些實施例所繪示的訊號量測方法的流程圖； 第3圖為根據本發明一些實施例所繪示的輸入訊號的示意圖； 第4圖為根據本發明一些實施例所繪示的第1圖中的頻移訊號的其中一種實施例的示意圖； 第5圖為根據本發明一些實施例所繪示的第1圖中的頻移訊號的另一種實施例的示意圖； 第6圖為根據本發明一些實施例所繪示的第1圖中的低頻訊號的其中一種實施例的示意圖；以及 第7圖為根據本發明一些實施例所繪示的第1圖中的低頻訊號的另一種實施例的示意圖。 In order to make the above and other objects, features, advantages and embodiments of the present disclosure more obvious and understandable, the accompanying drawings are described as follows: Figure 1 is a schematic diagram of a Doppler ultrasound system according to some embodiments of the present invention; Figure 2 is a flow chart of a signal measurement method according to some embodiments of the present invention; Figure 3 is a schematic diagram of input signals according to some embodiments of the present invention; Figure 4 is a schematic diagram of one embodiment of the frequency shift signal in Figure 1 according to some embodiments of the present invention; Figure 5 is a schematic diagram of another embodiment of the frequency shift signal in Figure 1 according to some embodiments of the present invention; Figure 6 is a schematic diagram of one embodiment of the low-frequency signal in Figure 1 according to some embodiments of the present invention; and FIG. 7 is a schematic diagram of another embodiment of the low-frequency signal in FIG. 1 according to some embodiments of the present invention.
200:訊號量測方法 200: Signal measurement method
S210,S230,S250,S270,S290:步驟 S210, S230, S250, S270, S290: steps
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| US20050068221A1 (en) * | 2003-09-30 | 2005-03-31 | Freeman Steven R. | Ultrasonic signal acquisition in the digital beamformer |
| US20070282203A1 (en) * | 2004-10-20 | 2007-12-06 | Kabushiki Kaisha Toshiba | Ultrasonic Doppler Diagnosis Device |
| US20150045666A1 (en) * | 2013-08-09 | 2015-02-12 | Sonowise, Inc. | Systems and Methods for Processing Ultrasound Color Flow Mapping |
| US20150094592A1 (en) * | 2013-09-27 | 2015-04-02 | Texas Instruments Incorporated | Method and Apparatus for Low Complexity Ultrasound Based Heart Rate Detection |
| TW201902425A (en) * | 2014-04-18 | 2019-01-16 | 美商蝴蝶網路公司 | Ultrasonic imaging compression method and device |
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| US20050068221A1 (en) * | 2003-09-30 | 2005-03-31 | Freeman Steven R. | Ultrasonic signal acquisition in the digital beamformer |
| US20070282203A1 (en) * | 2004-10-20 | 2007-12-06 | Kabushiki Kaisha Toshiba | Ultrasonic Doppler Diagnosis Device |
| US20150045666A1 (en) * | 2013-08-09 | 2015-02-12 | Sonowise, Inc. | Systems and Methods for Processing Ultrasound Color Flow Mapping |
| US20150094592A1 (en) * | 2013-09-27 | 2015-04-02 | Texas Instruments Incorporated | Method and Apparatus for Low Complexity Ultrasound Based Heart Rate Detection |
| TW201902425A (en) * | 2014-04-18 | 2019-01-16 | 美商蝴蝶網路公司 | Ultrasonic imaging compression method and device |
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