1258003 九、發明說明： 【發明所屬之技術領域】 本發明係有關一種測距裝置及其測量方法，特別是指一種變頻式雷射 測距裝置及其方法。 【先前技術】 雷射測距方式共分成飛行時間量測、相位差量測及三角原理量测等= 鲁 種方式’其中相位差量測是利用雷射光照射目標物時，反射光經價測哭、產 生反射光之電訊號與參考波電訊號之間的相位差來求得目標物的距離， 由於相位係以27Γ為週期’所以相位測距法會有測量距離上的限制，其測 量範圍約數十米，精度則約達釐米級。 習知技術如第一圖所示，射頻震盪器（RF oscillator) 40及本地震盪器' (Local oscmator)42為兩個頻率產生器，分別產生射頻如和本地頻率u， 其中一射頻訊號％驅動雷射二極體44產生之雷射光訊號發射至目標物奶 • 上，經反射由偵測器48接收轉換成電訊號後，利用平衡混波器5〇與心訊 號混波，產生中頻flN的測距訊號乂沿）；另一射頻訊號直接與L訊號混波 產生中頻知的參考訊號％⑴。％⑴和％⑴分別經過同架構之第一鎖相迴路 52和第二鎖相迴路54，由於鎖相迴路52、％中具有鎖定相位與除頻功能， 因此二訊號的相位差可由相位計56輸出為原始相位差的N倍。此裝置雖然 、測距精度提高，但調制訊號固定，因此測距範圍無法改變，且電路中使用 -個軸鹏，及二個混波H，使電路較娜且誤差較大。 另一習知技術如第二圖所示，石英震盪器58產生大範圍測距用的低頻 1258003 sfU虎、咼精度的高頻訊號、混波用的中頻訊號以及取樣訊號，高頻訊號與 雷射光耦合發射至目標經接收器接收解調後與中頻訊號混波並取樣，低頻 訊號以相同方式制侧減，但不射頻職混波，直接取樣。上述所 得相位均包含電路本身產生之相位，而電路本身產生之相位可藉由訊號直 接取樣獲得。此裝置的電路本身只提供固定的調制訊號，因此測距範圍及 精度無法改變，且電路巾需要五個切換關及—舰波器，製作複雜且增^ 加測量誤差。 _ 目此’本發明即針對上述f知技狀數項缺失，提iB-種變頻式雷射 測距裝置及其方法，以有效克服上述之該等問題。 【發明内容】 本I明之主要目的在提供一種變頻式雷射測距裝置及其方法，其係利 單鎖相k路達到多選擇性的調制頻率，並固定取樣頻率，讓使用者可 根據欲測侧制鮮，制實際贿無需之精確 • 度。 本毛月之$目的在提供一種變頻式雷射測距裝置及其方法，I係利 用較先前簡⑽之魏辦，魏本及綠猶低。 本發明之又一目沾+ & , 的在k供一種變頻式雷射測距裝置及其方法，其係利 用τ私式鎖相題路對調制訊號的頻率進行調整，因此測距範圍和精度可 隨之改變。 — 之又目的在使用次取樣理論(under sampUng th H吏該取樣 頻率可不必因高、假士 -或中頻訊號之不同而改變其取樣頻率，並因此免除頻， 6 1258003 率混波器之需求。 _ 本發明之再—目的在提供—觀狱雷射觀裝置及其方法，其係可 應用在各種非接觸距離測量上，如建築物之高度測量、物體定位、高爾夫 球場之測距及機器人_距裝„，若將其製作鑛描式，射產生三維 距離圖像。 為達上述之目的’本發贿供—種㈣式雷射測距裝置及其方法，其 鲁侧用/體震盪器發出—調制訊號及—取樣訊號，其中該調制訊號可傳 k至可私式鎖相迴路，以控制該調制訊號之頻率，而取樣訊號利用一除 頻器降低取樣頻率；該調制訊號與一雷射二極體中之光訊號搞合，而· 。後之田射光錢職雜射二極體發射至—目標物上；該雷射光訊號經 該目仏物反射後由-接收器接收調解成_接收訊號，並將該接收訊號傳送 至-類比數轉換器進行處理，錢將雜㈣號猶該取樣訊號之頻率 做取樣的動作，並將該取樣之結果傳送至—資料處理器以計算出該雷射二 魯極體與該目標物之距離。本發明之構件較習知技術簡單，且調制訊號可藉 由可程式鎖相迴路做調整，可依使用者的需要選擇適當的操作頻率。 底下藉由具體實施例詳加說明，當更容易瞭解本發明之目的、技術内' 容、特點及其所達成之功效。 【實施方式】 帛三圖可用以說明本發_提供之-種變頻式雷射測距裝置及其方 -法’如圖所不’一石英震盡器10做為頻率產生器，其發出-調制訊號及-取樣訊號’並確保兩訊號之初始相位是鎖住的，其中調制訊號經過一可程 1258003 式鎖相迴路12調變後，其頻率為fc，取樣訊號則通過一除頻器22後得到 一較低之取樣頻率心；調制訊號在經調變後通過一電路切換器32，此時因， 電路切換器32並未啟動，因此調制訊號沒有產生任何變化即傳送至一雷射 二極體14 ;該調制訊號驅動雷射二極體14產生雷射光並發射至一目標物 16上。 此雷射光訊號被目標物16反射回本發明之裝置，由一接收器18中之 光接收器（圖中未示）所接收，此接收器18將雷射光訊號解調成一接收訊 號後，經過另一無作動之電路切換器34傳送至一類比數位轉換器2〇 ;另一 方面，該取樣頻率f印之取樣訊號先經過放大器24和史密特觸發器（Schmitt trigger) 26以獲得較佳的取樣脈波，接著同樣被傳送至類比數位轉換器如 中嚥收訊號麵比數位轉換器财尊樣訊號之頻率&作為取樣依據可 得- 乂仙數位峨，並將取樣之結果傳送至一資料處理器&巾進行處理。 為V 1¾¾本身戶斤造成之相位位移而做修正，此時可利用微處理器 及校準元件36控制電路切換器32、34,使調制訊號在_校準元#36後， 直接傳送至類比數位轉換器20，再以相同取樣頻率^對調制訊號進行取 17 '寻另、、a Va^位滅’電路本身所造成之相位位移可由資料處理 器28，將電路所產生之相位差扣掉。 資料在資料處理器28内之處理過程如第四圖所示，在步驟S10中，高 頻和低頻f0L的調制訊號與取樣職SD[k]分別和程式所產生之剛及 RQM相乘，其巾_滅_畅可程式目迴路㈣為高頻或低頻， 接著如步驟S12所述做反正切函數的運算，料數範圍落在々AM之 1258003 間，再經過步驟S14相位展開將相位轉到〇〜2禮，可如步驟训到伽 所述求得距離及騎度，最後_尺度合併的計算制高精度的距離。此 部份由相位求得距離之計算過程如下所示，在雷射光訊勤雷射二極體發 出’到接收ϋ接收’以相㈣觀點來看，此触必定產生她改變，其可 表示成： (Ο Ψ = 2π{〇ίά = 2π f〇(2d/c) 其中f〇為調制頻率，td為光行進時間，d為距離，c為光速。由上式可知接 收器與目標物間距離為 d = (c/2f〇)( φ/2 π) 由於相位每經過2 7Γ就會重複(non-ambiguityrange，NAR)為： NAR = c/2f〇對公式（2)微分可得解析度為： δ ά/ δ φ-ο/Απΐο (2) ，因此由公式（2 )得可靠量測範圍 (3) (4) 雷射二極體經fG的頻率調變後，射出的光波與接收的訊號可分別表示成： / SE(t)=SE[a + cos(2 7Tf〇t)] ( 5 )1258003 IX. Description of the Invention: [Technical Field] The present invention relates to a distance measuring device and a measuring method thereof, and more particularly to a variable frequency laser ranging device and a method thereof. [Prior Art] The laser ranging method is divided into flight time measurement, phase difference measurement and triangulation measurement, etc. = Lu method "When the phase difference measurement is to irradiate the target with laser light, the reflected light is subjected to price measurement. Cry, generate the phase difference between the reflected signal and the reference wave signal to obtain the distance of the target. Since the phase system has a period of 27 ', the phase ranging method has a limit on the measurement distance, and its measurement range About tens of meters, the accuracy is about centimeter. As shown in the first figure, the RF oscillator 40 and the local oscillator oscillator 42 are two frequency generators, respectively generating a radio frequency such as a local frequency u, wherein one RF signal is driven by %. The laser light generated by the laser diode 44 is emitted to the target milk, and is received by the detector 48 after being converted into a signal by reflection, and then mixed with the heart signal by the balanced mixer 5 to generate an intermediate frequency flN. The distance measurement signal is edged; another RF signal is directly mixed with the L signal to generate the intermediate frequency known reference signal %(1). %(1) and %(1) respectively pass through the first phase-locked loop 52 and the second phase-locked loop 54 of the same architecture. Since the phase-locked loop 52 and % have the locking phase and the frequency dividing function, the phase difference of the two signals can be obtained by the phase meter 56. The output is N times the original phase difference. Although the accuracy of the ranging and the accuracy of the device are fixed, the modulation signal is fixed, so the ranging range cannot be changed, and the circuit uses - a shaft, and two mixed waves H, so that the circuit is relatively large and the error is large. Another conventional technique, as shown in the second figure, the quartz oscillator 58 generates a low frequency 125083 sfU for large range ranging, a high frequency signal with high precision, an intermediate frequency signal for mixing, and a sampling signal, high frequency signal and The laser light is coupled to the target and received by the receiver for demodulation and then mixed with the intermediate frequency signal and sampled. The low frequency signal is side-reduced in the same way, but the RF carrier is not directly sampled. The above-mentioned phases all include the phase generated by the circuit itself, and the phase generated by the circuit itself can be obtained by direct sampling of the signal. The circuit itself of the device only provides a fixed modulation signal, so the range and accuracy of the measurement cannot be changed, and the circuit towel needs five switching and the ship wave, which is complicated to manufacture and increases the measurement error. The present invention is directed to the above-mentioned f-technical number missing, and the iB-type variable-frequency laser ranging device and method thereof are provided to effectively overcome the above problems. SUMMARY OF THE INVENTION The main object of the present invention is to provide a variable frequency laser ranging device and a method thereof, which are capable of achieving a multi-selective modulation frequency and a fixed sampling frequency, so that the user can Measuring the side of the fresh, the actual bribe does not need to be precise. The purpose of this month is to provide a variable-frequency laser ranging device and its method. The I system is lower than the previous Wei (10), Wei Ben and Green. Another object of the present invention is to provide a variable-frequency laser ranging device and method thereof for adjusting the frequency of the modulated signal by using the τ private phase-locking path, so the ranging range and accuracy are Can change accordingly. - The purpose is to use the subsampling theory (under sampUng th H 吏 the sampling frequency does not have to change its sampling frequency due to high, false - or intermediate frequency signals, and therefore free of frequency, 6 1258003 rate mixer _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The robot _ distance „, if it is made into a mining style, the shot produces a three-dimensional distance image. For the above purpose 'this bribe-type (four) type laser ranging device and its method, its side use / body The oscillator emits a modulated signal and a sampled signal, wherein the modulated signal can be transmitted to a private phase-locked loop to control the frequency of the modulated signal, and the sampled signal is reduced by a frequency divider; the modulated signal is The optical signal in a laser diode is engaged, and the rear field light-emitting dipole is emitted to the target; the laser light is reflected by the target and received by the receiver Mediation into _ receiving No., and the receiving signal is transmitted to the analog-to-digital converter for processing, and the money is sampled by the frequency of the sampling signal, and the result of the sampling is transmitted to the data processor to calculate the lightning The distance between the two-pole body and the target object is simpler than the conventional technique, and the modulation signal can be adjusted by the programmable phase-locked loop, and the appropriate operating frequency can be selected according to the user's needs. The details of the present invention, the contents, the features, and the effects achieved by the present invention are more easily understood. [Embodiment] The third figure can be used to illustrate the present invention. The radiation ranging device and its square-method 'as shown in the figure' are a quartz resonator 10 as a frequency generator that emits a -modulation signal and a -sampling signal and ensures that the initial phase of the two signals is locked, wherein After the modulation signal is modulated by a programmable 1258003 phase-locked loop 12, the frequency is fc, and the sampling signal passes through a frequency divider 22 to obtain a lower sampling frequency center; the modulated signal passes through a circuit after being modulated. cut 32, at this time, since the circuit switch 32 is not activated, the modulation signal is transmitted to a laser diode 14 without any change; the modulation signal drives the laser diode 14 to generate laser light and emits it to a The target light 16 is reflected by the object 16 back to the apparatus of the present invention, and is received by a light receiver (not shown) in a receiver 18, and the receiver 18 demodulates the laser light signal into a After receiving the signal, the other inactive circuit switcher 34 is sent to an analog converter 2; on the other hand, the sampling signal of the sampling frequency f is first passed through the amplifier 24 and the Schmitt trigger. 26 to obtain a better sampling pulse, and then also transmitted to the analog digital converter, such as the frequency of the medium-to-speech signal-to-digital converter, and the sampling frequency is available as a sampling basis - The results of the sampling are sent to a data processor & towel for processing. Correction is made for the phase shift caused by the V 13⁄4⁄4 itself. At this time, the microprocessor and the calibration component 36 can be used to control the circuit switches 32 and 34, so that the modulated signal is directly transmitted to the analog digital conversion after the _ calibration element #36. The phase shift caused by the circuit itself is taken by the data processor 28, and the phase difference generated by the circuit is deducted by the data processor 28 by taking the same sampling frequency ^ to take the 17' 'seeking, a Va^ bit off' circuit phase. The processing of the data in the data processor 28 is as shown in the fourth figure. In step S10, the high-frequency and low-frequency f0L modulation signals are multiplied by the sampling job SD[k] and the RQM generated by the program, respectively. The towel_extinguishable circuit (4) is a high frequency or a low frequency, and then the inverse tangent function is performed as described in step S12. The range of the material falls between 125803 of 々AM, and then the phase is shifted by step S14. 〇~2 rituals, as in the step of training to find the distance and riding degree, the final _ scale combined calculation of the high-precision distance. The calculation process of this part from the phase-derived distance is as follows. In the laser light-emitting diode, the laser diode emits 'to receive/receive'. From the point of view (4), this touch must produce her change, which can be expressed as :(Ο Ψ = 2π{〇ίά = 2π f〇(2d/c) where f〇 is the modulation frequency, td is the light travel time, d is the distance, and c is the speed of light. The distance between the receiver and the target is known from the above equation. For d = (c/2f〇)( φ/2 π), the phase is repeated every 2 7 ( (non-ambiguity range, NAR) is: NAR = c/2f 〇 The formula (2) differential can be obtained as : δ ά / δ φ-ο/Απΐο (2) , so the reliable measurement range is obtained by the formula (2) (3) (4) After the laser diode is modulated by the frequency of the fG, the emitted light wave and the received light The signals can be expressed as: / SE(t)=SE[a + cos(2 7Tf〇t)] ( 5 )
Sd⑴=έ D[a + cos(2 7Γ f〇t + Ψ d+ 0 e)] ( 6 ) 其中¥d是光在行鱗所產生_位位移，（是_訊號在脑内產生的 相位位移，職發射和接㈣光波函數，雷㈣訊號輸出沒有負 值，因此公式中需加入直流項a。 再利用次取樣（undefsampling)獅，以fsp為轉齡，nfsp為最接近 1258003 f〇的頻率（η為整數）’接收的訊號經過取樣後可表示成下列公式： ' s〇[k] =S D[a + cos(2 π f〇kTSP+ ¥d+ 0 e)] ⑺ 其中TSP-l/fSP’k疋整數。接著用頻率為nfsp的同步訊號见閃=sin(2 ;rfALkTSP)和RQ[k] - cos(2 7rfALkTSP)與接收訊號SD[k]相乘，產生新的訊號 MI[k]和 MQ[k]。若 2 疋 fALkTSP = k 7Γ /2，則 fSP= 4 f〇/(4n+l)，RI[k] = sin(k tt/2) ’ RQ[k] = C〇s(k;r/2)，其中fSP=4f〇/(4n+l)此項關係式，可藉由調整調 制訊號之頻率f〇達到。亦即當取樣頻率與調制頻率有上述關係時，^[k]和 > MQ[k]的計算如下： MI[k] = sD[k] x RI[k] ~ {a + cos[2 7Γ f〇kTSP+(Ψd+ 0 e)]}sin(k π /2) =l/2{ cos[(2n+l)k7r]sin(Wd+(/)e)-sin(Wd+0e)} + a x sin(k7r/2) (8) MQ[k] = sD[k] x RQ[k] ={a + c〇s[2 7Γ ^ΤδΡ+(ψ(1+ φ e)]}c〇s(k π /2) =l/2{ cos[(2n+l)k7T]cos(Wd+0e)+cos(Wd+0e)} + a x cos(k7r/2) (9) 以四個k值為一組，k為奇數時，MI[k]取平均得Ave(MI[k]) ; k為偶數時， MQ[k]取平均得Ave(MQ[k])。如下表一所示，其為k=〇〜3時^闳及MQ[k] 之值。 10 1258003 表一 k —^_ MI[k1 ______MQrkl 0 0 〜—_ ---------1 ___ a+cos(^d+0e) 1 a-sin(¥d+0e) ~~——— 0 2 0 -a+cos(Wd+0e) 3 -a-sin(Wd+0e) ---- 0Sd(1)=έ D[a + cos(2 7Γ f〇t + Ψ d+ 0 e)] (6) where ¥d is the displacement of the light produced by the scale, (is the phase shift produced by the signal in the brain, Job transmission and connection (four) light wave function, Ray (four) signal output has no negative value, so the formula needs to add DC item a. Then use the sub-sampling (undefsampling) lion, with fsp as the age, nfsp is the frequency closest to 1258003 f〇 ( η is an integer) 'The received signal can be expressed as the following formula after sampling: ' s〇[k] =SD[a + cos(2 π f〇kTSP+ ¥d+ 0 e)] (7) where TSP-l/fSP'k疋 integer. Then use the synchronization signal with frequency nfsp to see flash = sin(2; rfALkTSP) and RQ[k] - cos(2 7rfALkTSP) multiplied by the received signal SD[k] to generate a new signal MI[k] and MQ[k]. If 2 疋fALkTSP = k 7Γ /2, then fSP= 4 f〇/(4n+l), RI[k] = sin(k tt/2) ' RQ[k] = C〇s( k;r/2), where fSP=4f〇/(4n+l) can be achieved by adjusting the frequency f〇 of the modulated signal, that is, when the sampling frequency has the above relationship with the modulation frequency, ^[ The calculation of k] and > MQ[k] is as follows: MI[k] = sD[k] x RI[k] ~ {a + cos[2 7Γ f〇kTSP+(Ψd+ 0 e)]}sin(k π /2) =l/2{ cos[(2n+l)k7r]sin(Wd+(/)e)-sin(Wd+0e)} + ax sin(k7r/2) (8) MQ[k] = sD[k] x RQ[k] ={a + c〇s[2 7Γ ^ΤδΡ+(ψ(1+ φ e)]}c〇s(k π /2) = l/2{ cos[(2n+l)k7T]cos(Wd+0e)+cos(Wd+0e)} + ax cos(k7r/2) (9) with four k values, k is odd When MI[k] takes the average Ave(MI[k]); when k is even, MQ[k] takes the average Ave(MQ[k]). As shown in Table 1 below, it is k=〇~3. Time ^闳 and the value of MQ[k] 10 1258003 Table I k —^_ MI[k1 ______MQrkl 0 0 ~—_ ---------1 ___ a+cos(^d+0e) 1 a -sin(¥d+0e) ~~——— 0 2 0 -a+cos(Wd+0e) 3 -a-sin(Wd+0e) ---- 0
相位可由下式求得，同時直流項&亦被消除， ^d+ 0 e - tan ^AveCMIMyAveCMQfk])] (1〇) 由於反正切函數tan“的值定義在^/2到7Γ/2之間，因此公式（10)所 付到的相位亦為’π/2到疋/2。反正切函數之分子分母的正負號分別對應了 sm^和eGS0之正負號，然而正弦、餘弦是以2福週期的連續函數，因此 可藉由反正切函數的分子分母之正負來姻相位中的象賴在。利用下表 二的象限判斷表可將相位展開至〇到2?r的範圍，此方法稱細立展開技術 (phase unwrapping ) 〇 表二 正 弦 餘 弦 正確相位 Wd 相位範圍 正 弦 餘 弦 正確相位 ψά ------- 相位範圍 0 + 0 0 — —--— π ------ π + + Wd 0 〜;ζ72 —— — ——~.— Wd+7T --—— π-3 π /2 + 0 π 12 π 12 —— 0 3 7Γ/2 一—.. 3 7γ/2 + — Wd+ττ π 11 〜π — + Ψ(ΐ+2 π , ——._-- 3 π /2-2 π 1258003 -若收發器與目標物距離為〇，同樣的方法可得到^，將公式（1〇)減 去_科相位位移，再_公式⑵求得距離。其中，當_高時， 测距耗圍低但崎度局，&鮮辦，舰範職轉析度低。 紅上所述，本發明為一種變頻式雷射測距裝置及其方法其係固定取’ 樣頻率，並细-可程式目迴_整_峨之鮮，達财選擇性的 調製頻率，因此使用者可根據欲測量之距離選擇適當的兩個頻率，加以計 春讀得到實際距離；且本發明之電路較先前技術更為簡化，不僅鎖相迴路 只需-個、切換開關只需兩個，更不需混波器，可大為降低誤差及成本。 唯以上所述者，僅為本發明之較佳實施例而已，並非用來限定本發明 實施之範圍。故即凡依本發明申請範圍所述之特徵及精神所為之均等變化 或修飾，均應包括於本發明之申請專利範圍内。The phase can be obtained by the following equation, and the DC term & is also eliminated, ^d+ 0 e - tan ^AveCMIMyAveCMQfk])] (1〇) Since the value of the arc tangent function tan " is defined between ^/2 to 7Γ/2 Therefore, the phase paid by equation (10) is also 'π/2 to 疋/2. The sign of the numerator and denominator of the inverse tangent function corresponds to the sign of sm^ and eGS0, respectively, but the sine and cosine are 2 The continuous function of the period, so the positive and negative of the numerator and the denominator of the arctangent function can be used to approximate the image in the phase. The quadrant of the quadrant in Table 2 can be used to expand the phase to the range of 2?r. Phase unwrapping 〇 Table 2 sine cosine correct phase Wd phase range sine cosine correct phase ψά ------- phase range 0 + 0 0 — — — — π π π + + Wd 0 〜;ζ72 ——————~.— Wd+7T --—— π-3 π /2 + 0 π 12 π 12 —— 0 3 7Γ/2 one —.. 3 7γ/2 + — Wd+ττ π 11 ～π — + Ψ(ΐ+2 π , ——._-- 3 π /2-2 π 1258003 - If the distance between the transceiver and the target is 〇, the same method can get ^, the formula 1〇) Subtract _ section phase shift, then _formula (2) to find the distance. Among them, when _ high, the range is low, but the bargaining degree, & fresh, the ship's role is low. According to the present invention, the present invention is a variable frequency laser ranging device and a method thereof, which are fixed to take a sample frequency, and are fine-programmable, and the user selects a modulation frequency. The appropriate two frequencies can be selected according to the distance to be measured, and the actual distance can be obtained by reading the spring; and the circuit of the present invention is more simplified than the prior art, not only the phase-locked loop but only two switches and only two switches. Without the need for a mixer, the error and the cost are greatly reduced. The above is only a preferred embodiment of the present invention and is not intended to limit the scope of the practice of the present invention. Equivalent changes or modifications to the characteristics and spirit of the invention are intended to be included in the scope of the invention.
12 1258003 【圖式簡單說明】 第一圖及第二圖為習知技術之示意圖。 第三圖為本發明之方塊圖。 第四圖為本發明資料處理器之計算流程圖。 【主要元件符號說明】 10石英震盪器 14雷射二極體 18接收器 22除頻器 26史密特觸發器 30微處理器 36校準元件 42本地震盪器 46目標物 50平衡混波器 54第二鎖相迴路 58石英震盪器 12可程式鎖相迴路 16目標物 20類比數位轉換器 24放大器 28資料處理器 32、34控制電路切換器 40射頻震盪器 44雷射二極體 48偵測器 52第一鎖相迴路 56相位計 1312 1258003 [Simple description of the drawings] The first and second figures are schematic diagrams of the prior art. The third figure is a block diagram of the present invention. The fourth figure is a flow chart of calculation of the data processor of the present invention. [Major component symbol description] 10 quartz oscillator 14 laser diode 18 receiver 22 frequency divider 26 Schmitt trigger 30 microprocessor 36 calibration component 42 this oscillator 46 target 50 balance mixer 54 Second phase-locked loop 58 quartz oscillator 12 programmable phase-locked loop 16 target 20 analog-bit converter 24 amplifier 28 data processor 32, 34 control circuit switcher 40 RF oscillator 44 laser diode 48 detector 52 First phase locked loop 56 phase meter 13