200848766 九、發明說明： 【發明所屬之技術領域】 本發明係有關於一種調變連續波雷達之收裝置，其係尤指一種低雜訊 寬頻之調變波雷達之收發裝置。 【先前技術】 按，現今無線通訊技術係相當發達，其中雷達之應用係為現今發展相 當成熟之技術，特別是應用於目標偵測追蹤之用途。調頻連續波(Frequency Modulation Continue Wave，FMCW)雷達之基本技術是發射一種頻率隨時間 變化的直線掃頻訊號，直線掃頻訊號傳至地面或物體後而產生反射訊號， 該反射訊號隨距離之遠近產生相對的時間延遲，使反射訊號與發射訊號混 波後產生差頻（Beat Frequency)而輸出，如此可經由訊號處理換算而得知 高度或距離。 明併參閱第一 A圖與第一 β圖，其係為為習知技術之調頻連續波雷 達發射波與反射波之調頻曲線圖以及發射波與反射波之差頻的曲線圖。如 圖所示，當調頻連續波雷達發射直線掃頻訊號作為發射波，並於一延遲時 間Td接收反射訊號，並由下列計算式可得知一差頻比· fb=w^s................ 其中τ為掃頻時間（sweep time)，c為光速，Fs騎頻頻寬㈤卿 bandwidth)，R為待測物體的距離。由上式可知，當R越大而&亦越大； 而fb即^頻濾波运至數位訊號處理⑼gital抑㈣加咖咖，㈣ 電路以心轉’所以為了偏林變之頻寬以簡化設計之複雜度並保持量 測之度’ fb應保持於—定職内，故調整掃麵寬為最佳的掃頻方式。 π二般調頻連續波雷達多採用壓控振盡器㈤tage Controlled a or VCO)，並配合電壓掃描產生電路，以產生直 者，壓控振盪器可額外配合鎖相電路，以敎的石英晶體缝骑U 振盡訊號料參考喊，壓控紐^頻轉減齡參考 200848766 頻率的度。鎖相電路雖可提高頻率穩定度，但必須靠軟體來切換頻道， 而且^她迴Ϊ之親城慢，麵道切換時，將會影響信號之相雜訊。 节於ψ右！在：際的队中’連續波雷達如直接採用壓控振盪11為掃瞒訊 =輸出’ k壓控振1器之線性度與壓控振盪器之頻率隨 制，如_觸達之距離與速度崎度。再者，為了改善軸H ，線掃頻訊號之頻树性纽鮮度，所以在應社需要_的電壓掃瞒 生電路％皿度補j貝電路以校正壓控振蘆器之頻率線性度與頻率飄移，如 此而耗費t作上的成本。又’壓控振盪器之頻率穩定度（㈣·^ stability)與相編(phase職se)不佳之躲，使觸連續 距離受到相當之限制。 【發明内容】 本發明之目的之-，在於提供一種調頻連續波雷達之收發裝置，其藉 由-直接錄合成t路並配合—細介冑共聽m||(phase—圆 產生低雜訊之一掃頻連續波訊號。 本發明之目❸之―’在於提供—翻頻連續波雷達之W裝置，其藉 由具有低相雜訊(Phase noise)與溫度補償之參考時脈作為直接數位合成電 路與鎖相電路的翏考時脈，明加掃頻連續波城的溫定敎度與低相雜 訊之效能。 本發明之目的之一，在於提供一種調頻連續波雷達之收發裝置，其在 接收裝置設置-隔離ϋ，以降低反射酬—混波㈣功率而改善接收機的 靈敏度。 本發明之調頻連續波之收發裝置，其發射裝置包含一直接數位合成電 路、一鎖相電路、一振盪電路、一混波器與一濾波器。直接數位合成電路 接收一輸入貧料與一參考時脈而產生一掃頻訊號，鎖相電路接收參考訊號 而產生一鎖相訊號’振盪電路接收該鎖相訊號，並產生一振盪訊號且傳送 至鎖相電路’ _電路依據參考訊賴相振舰號而產生鎖相減，混波 6 200848766 器混f頻訊號與鎖相訊號而產生—混波訊號，濾波器過航波訊號而產 生「掃頻連續波訊號，減分離器分離掃頻連續波減而產生—本地振盈 訊號，並輸出掃頻連續波訊號與本地振盪訊號。 一再者’接收裝置包含-濾波n、_隔離器、—混波器與—增益控制單 元濾、波為接收掃頻連續波訊號，並過濾掃頻連續波訊號而產生一過渡訊 號，隔離器接收過濾、訊號而產生—隔離訊號，混波器接收本地減訊號與 隔離訊號喊生-輸出訊號，增益控制單元接錄出訊號並輸出至一類比 數位轉換電路，以轉換輸出訊號為—數位資料，並回傳至增益控制單元， 增盈控制單元依據數位資料而控制輸出訊號之增益。 【實施方式】 茲為使貴審查委員對本發明之結構特徵及所達成之功效有更進一步 之瞭解與認識，謹佐以雛之實施例及配合詳細之·，說明如後： 明闕第二圖，其為本發明之一較佳實施例之發射裝置之方塊圖。如 圖所不，本發明之觸連較雷達之收發裝置，其發職置包含—直接數 位合成電路 10 (Direct-Digital Synthesis，DDS)、一訊號產生器 12、一 鎖相電路20…振i電路22、-混波n 14、-濾、波器16與-訊號分離器 18。直接數位合成電路1〇接收一輸入資料與訊號產生器12產生之一參考 時脈而產生一掃頻訊號，其中，由於直接數位合成電路1〇具有可程式化的 特H ’所以可產生南精確度及線性度佳的掃^^員波形。再者，訊號產生器u 為，皿度補核晶體振盪器（Temperature compensated crystal oscillator ^ TCXO)^-M>^f^^a^^||(〇Ven controlled crystal osciilator，0CX0) ’如此訊號產生器丨2所產生的參考訊號具有低相雜訊 與溫度補償的功效，故可增加雷達的溫度穩定性。 鎖相電路20接收參考訊號而產生一鎖相訊號，振盪電路22接收鎖相 Λ號，產生一振盪訊號並傳送至鎖相電路2〇，鎖相電路2〇依據參考訊號鎖 相振盪§fl號而產生鎖相訊號，以避免振盪訊號發生飄移現象，混波器14混 200848766 波掃頻訊號與鎖相訊號而產生一混波訊號，濾波器16過濾混波訊號，以取 得適當範圍的混波訊號而產生一掃頻連續波訊號，訊號分離器18分離掃頻 連續波訊號而產生一本地振盪訊號，並輸出掃頻連續波訊號與本地振盡訊 號。 承上所述，由於直接數位合成電路10之相雜訊低，大約等於參考時脈 的相雜訊，所以只要使用具有溫度補償頻率穩定度高之參考時脈，即可使 直接數位合成電路10之輸出掃頻訊號的頻率具有極佳的相雜訊。再者，直 接數位合成電路10可產生高精確度、線性度佳的線性頻率掃描波形，因為 直接數位合成電路10的掃頻訊號之頻率控制字元長度很長，頻率步階 (frequency steps)可以調降至1Hz以下，故頻率準確度與掃描線性度佳。 又，直接數位合成電路10具有快速頻率掃描與切換之特性，所以適合用於 寬頻且需快速跳頻之雷達。此外，由於直接數位合成電路10之突波(spurs) 與諧波(harmonics)較高，故藉由濾波器16以選擇乾淨無雜訊的頻率範圍， 其中濾波器16為一帶通渡波器。 此外，本發明之振盪電路22為一介質共振振盪器（DielectHc Resonator Oscillator，DR0)。由於介質共振體(Dielectric Res〇nat〇r， 溫度穩定性並使相雜訊更低。 DR)之Q值可達數千’而騎f 體之_小，且可㈣溫度歡性佳之 陶紐料製成。因此在微波頻段中’可獲得高頻率純度(spectral purity) 與溫度歡性，崎低_訊與聽解飄移，再者，由於介質共振振盡 器之Q值高，所以頻寬窄約5MHz左右之調整細，故適合作為本地振盡訊 號或固定頻率訊號。又，振魏路22再加上鎖相電路2()與具有溫度補償 之多考Λ號而形成-鎖相介質共振振靈器（phase_1〇ckM励），可更增加 32與一除頻器34。倍頻器30接收 ，並傳送至直接數位合成電路10， 卜。倍頻器32接收掃頻訊號，乘一 丨14 ’以獲得發射裝置所需要之頻 再者，發射裝置更含一倍頻器3〇，3 參考訊號，乘一倍數於參考訊號之頻率， 以付合直接數位合成電路1Q所需的頻率 倍數於掃頻訊號之頻率並傳送至混波器 8 200848766 寬’並可藉由鎖相電路20與振盪電路22所形成之鎖相介質共振振盪器以 避免倍頻器32之倍數太高而使掃頻連續波訊號的相雜訊變差。除頻器34 接收振盤訊號’除一倍數於振盪訊號之頻率，並傳送至鎖相電路2〇以符合 鎖相電路20所需之頻寬。此外倍頻器30，32與除頻器34可依據系統的需 求而做適當的調整，甚至可使用除頻器34用於倍頻器30,32或倍頻器30， 32用於除頻器34。 接上所述’發射裝置更包含一放大器40、一低通濾波器42、一放大器 44與一功率放大器46。放大器40接收鎖相訊號，並放大鎖相訊號而輸出 鎖相訊號’低通濾波器42過濾放大器40放大後之鎖相訊號，並輸出至振 盈電路’以產生振盡訊號。放大器44接收掃頻連續波訊號，並放大掃頻連 續波訊號而輸出掃頻連續波訊號至訊號分離器18以分離掃頻連續波訊號。 1率放大器46接收訊號分離器18輸出之掃頻連續波訊號，並放大掃頻連 續波訊號而輸出掃頻連續波訊號，並使掃頻連續波訊號之功率達到3瓦 (watt) ’然後將此訊號傳送至發射天線，以便將訊紐射出去。200848766 IX. Description of the Invention: [Technical Field] The present invention relates to a receiving device for a modulated continuous wave radar, which is particularly a transceiver device for a low noise wideband modulated wave radar. [Prior Art] According to the current wireless communication technology system, the application of radar is a mature technology developed today, especially for target detection and tracking. The basic technique of the Frequency Modulation Continue Wave (FMCW) radar is to emit a linear sweep signal whose frequency changes with time. After the linear sweep signal is transmitted to the ground or an object, a reflected signal is generated, and the reflected signal is close to the distance. A relative time delay is generated, and the reflected signal is mixed with the transmitted signal to generate a beat frequency for output, so that the height or distance can be known by signal processing conversion. Referring to the first A picture and the first β picture, which is a frequency modulation curve of a modulated continuous wave radar wave and a reflected wave and a difference frequency of a transmitted wave and a reflected wave, which are conventional techniques. As shown in the figure, when the frequency modulated continuous wave radar emits a linear sweep signal as a transmitted wave, and receives a reflected signal at a delay time Td, a difference frequency ratio can be known from the following formula: fb=w^s... ............. Where τ is the sweep time, c is the speed of light, Fs rides the bandwidth (5), and R is the distance of the object to be tested. It can be seen from the above formula that when R is larger and & is larger, and fb is transmitted by frequency filter to digital signal processing (9) gital (four) plus café, (four) circuit to heart turn 'so in order to simplify the width of the forest to simplify The complexity of the design and the degree of measurement 'fb should be kept within the time limit, so adjust the sweep width to the best way to sweep. π two-way frequency modulation continuous wave radar mostly uses a voltage-controlled vibrator (5) tage Controlled a or VCO), and with the voltage scanning to generate a circuit to produce a straight, voltage-controlled oscillator can be additionally equipped with a phase-locked circuit, with a quartz crystal seam Riding U to reverberate the signal reference shouting, pressure control New Zealand frequency to age reduction reference 200848766 frequency degree. Although the phase-locked circuit can improve the frequency stability, it must rely on the software to switch channels, and ^ she will return to the pro-city slow, when the switch is switched, it will affect the signal noise. Festival is right! In the inter-team, 'continuous wave radar, such as direct use of voltage-controlled oscillation 11 for brooming = output 'k voltage control, the linearity of the oscillator and the frequency of the voltage-controlled oscillator, such as _ touch distance and Speed and roughness. In addition, in order to improve the frequency H of the axis H and the line sweep signal, the voltage sweeping circuit of the voltage sweeping circuit is required to correct the frequency linearity of the voltage controlled vibrator. The frequency drifts, so it costs a lot of money. Moreover, the frequency stability of the voltage-controlled oscillator ((4)·^ stability) and the phase editing (phase job se) are poorly hidden, so that the continuous distance of the touch is quite limited. SUMMARY OF THE INVENTION The object of the present invention is to provide a transceiving device for frequency-modulated continuous wave radar, which directly synthesizes a t-channel and cooperates with a fine-tuned m_| (phase-circle generates low noise) One of the objectives of the present invention is to provide a W-channel continuous wave radar W device with direct phase synthesis by using phase noise with low phase noise and temperature compensation. The reference clock of the circuit and the phase-locked circuit, the performance of the temperature-sensing temperature and the low-phase noise of the frequency-sweeping continuous wave city. One of the objects of the present invention is to provide a transceiver device for frequency-modulated continuous wave radar. In the receiving device, the isolation device is provided to reduce the reverberation-mixing (four) power to improve the sensitivity of the receiver. The transmitting and transmitting device for the FM continuous wave device of the present invention comprises a direct digital synthesizing circuit, a phase-locked circuit, and a An oscillating circuit, a mixer and a filter. The direct digital synthesizing circuit receives an input lean and a reference clock to generate a sweep signal, and the phase lock circuit receives the reference signal to generate a phase lock signal. The oscillating circuit receives the phase-locked signal and generates an oscillating signal and transmits it to the phase-locked circuit. The circuit generates a phase-locked subtraction according to the reference signal, and the mixed wave 6 200848766 is mixed with the frequency signal and the phase-locked signal. - Mixing signal, the filter crosses the wave signal to generate "sweep continuous wave signal, reduce the splitter to separate the sweep continuous wave and generate - local vibration signal, and output the sweep continuous wave signal and local oscillation signal. The receiver includes a filter n, an isolator, a mixer and a gain control unit filter, a wave for receiving the swept continuous wave signal, and filtering the swept continuous wave signal to generate a transition signal, and the isolator receives the filter. And the signal is generated - the signal is isolated, the mixer receives the local subtraction signal and the isolation signal is called the output signal, and the gain control unit receives the signal and outputs it to an analog-to-digital conversion circuit to convert the output signal into digital data, and Returning to the gain control unit, the gain control unit controls the gain of the output signal according to the digital data. [Embodiment] Having further understanding and understanding of the structural features and the achievable effects of the invention, the following is a description of the embodiments and the details of the invention. The following is a description of the second embodiment, which is a preferred embodiment of the present invention. A block diagram of a transmitting device. As shown in the figure, the transmitting and receiving device of the touch-talking device of the present invention includes a direct-digital synthesis (DDS), a signal generator 12, and a The phase-locked circuit 20...the oscillator circuit 22, the mixer n 14, the filter, the waver 16 and the signal separator 18. The direct digital synthesis circuit 1 receives an input data and the signal generator 12 generates a reference clock. A sweep signal is generated, wherein the direct digital synthesizing circuit 1 has a programmable H', so that a sweeper waveform with good south precision and linearity can be generated. Furthermore, the signal generator u is a "Temperature compensated crystal oscillator ^ TCXO ^^M>^f^^a^^||(〇Ven controlled crystal osciilator, 0CX0) 'This signal is generated The reference signal generated by the device 2 has low phase noise and temperature compensation, so the temperature stability of the radar can be increased. The phase lock circuit 20 receives the reference signal to generate a phase lock signal, and the oscillating circuit 22 receives the phase lock apostrophe, generates an oscillating signal and transmits it to the phase lock circuit 2 〇, and the phase lock circuit 2 oscillates according to the reference signal phase lock §fl The lock signal is generated to avoid the drift of the oscillation signal. The mixer 14 mixes the 200848766 wave sweep signal and the lock signal to generate a mixed signal, and the filter 16 filters the mixed signal to obtain an appropriate range of the mixed wave. The signal generates a swept continuous wave signal, and the signal splitter 18 separates the swept continuous wave signal to generate a local oscillation signal, and outputs the swept continuous wave signal and the local vibrating signal. As described above, since the phase noise of the direct digital synthesizing circuit 10 is low, which is approximately equal to the phase noise of the reference clock, the direct digital synthesizing circuit 10 can be used as long as the reference clock having a high temperature compensation frequency stability is used. The frequency of the output sweep signal has excellent phase noise. Furthermore, the direct digital synthesizing circuit 10 can generate a linear frequency sweep waveform with high accuracy and good linearity, because the frequency control character of the sweep signal of the direct digital synthesizing circuit 10 is long, and the frequency steps can be The frequency is reduced to below 1 Hz, so the frequency accuracy and scanning linearity are good. Further, the direct digital synthesizing circuit 10 has the characteristics of fast frequency scanning and switching, and is therefore suitable for use in a wide-band radar which requires fast frequency hopping. In addition, since the spurs and harmonics of the direct digital synthesizing circuit 10 are high, the filter 16 is used to select a clean and noise-free frequency range, wherein the filter 16 is a bandpass ferrite. Further, the oscillation circuit 22 of the present invention is a dielectric resonance oscillator (DielectHc Resonator Oscillator, DR0). Due to the dielectric resonator (Dielectric Res〇nat〇r, temperature stability and lower phase noise. DR) Q value can reach several thousand ' while riding the body _ small, and (4) the temperature is good Made of materials. Therefore, in the microwave frequency band, 'spectral purity and temperature can be obtained, and the temperature is low. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ It is suitable for local vibration signal or fixed frequency signal. In addition, Zhenwei Road 22 plus phase-locked circuit 2 () and temperature-compensated multiple test number to form a phase-locked medium resonance oscillator (phase_1〇ckM excitation), can increase 32 and a frequency divider 34. The frequency multiplier 30 receives and transmits it to the direct digital synthesizing circuit 10, bu. The frequency multiplier 32 receives the frequency sweep signal, multiplies a 丨 14 ' to obtain the frequency required by the transmitting device, and the transmitting device further includes a frequency multiplier 3 〇, 3 reference signals, multiplied by a frequency of the reference signal, The frequency multiple required for the direct digital synthesizing circuit 1Q is multiplied to the frequency of the swept signal and transmitted to the mixer 8 200848766 wide 'and the phase-locked dielectric resonant oscillator formed by the phase locked circuit 20 and the oscillating circuit 22 The multiplier of the frequency multiplier 32 is prevented from being too high, so that the phase noise of the swept continuous wave signal is deteriorated. The frequency divider 34 receives the vibration plate signal 'divided by a multiple of the frequency of the oscillation signal and transmits it to the phase lock circuit 2' to match the bandwidth required by the phase lock circuit 20. In addition, the frequency multipliers 30, 32 and the frequency divider 34 can be appropriately adjusted according to the requirements of the system, and even the frequency divider 34 can be used for the frequency multiplier 30, 32 or the frequency multiplier 30, 32 for the frequency divider. 34. Further, the transmitting device further includes an amplifier 40, a low pass filter 42, an amplifier 44 and a power amplifier 46. The amplifier 40 receives the phase-locked signal, and amplifies the phase-locked signal to output a phase-locked signal. The low-pass filter 42 filters the amplified phase-locked signal of the amplifier 40 and outputs it to the oscillation circuit to generate a vibration signal. The amplifier 44 receives the swept continuous wave signal and amplifies the swept continuous wave signal and outputs the swept continuous wave signal to the signal splitter 18 to separate the swept continuous wave signal. The 1 rate amplifier 46 receives the swept continuous wave signal outputted by the signal splitter 18, and amplifies the swept continuous wave signal to output the swept continuous wave signal, and the power of the swept continuous wave signal reaches 3 watts (watt). This signal is transmitted to the transmitting antenna to shoot the signal out.
=參閱第二圖，其為本發明之一較佳實施例之接收裝置之方塊圖。如 圖所:，接收裝置包含一濾波器5〇、一隔離㈣52、一混波器、54與一增益 ^早=6。濾波器5Q接轉頻連續波訊餘過麟頻連續波訊號而產生 、，;慮减’隔離器52依據掃頻連續波訊號而產生-隔離訊號，即接收濾 50過濾掃頻連續波訊驗而產生之過濾、訊號，以產生隔離訊號。混波 =4翻咖條i訊號與_咖產生_輸出訊號，並藉由輸出訊號而 I/射^輸出㈣連續波訊號與接收裝置接收之掃頻連續波訊號間的 f增益控制單元56接收輸出訊號並輸出至-類比數位轉換電路(圖中 抑不）以轉換輸出訊號為_數位㈣，並回傳至增益控制單㈣，增益㈣ = 數位資料而控_出訊號之增益，如此可藉由數位資料體出 ’其中增盈控制單元56可依據數位資料之大小而自動調 7056之增益而可提高雷達價測動態範圍。 在上述中，由於調變連續波雷達侧時發射與接收掃頻連續波訊號， 200848766 且發射頻率與本地振盪訊號之頻率相同，故由本地振盪訊號漏進混波器54 之發射端，從濾波器50反射回來之訊號在混波器54與本地振盪訊號混頻， 產生極大之直流與低頻輸出，因此造成接收裝置的雜訊升高而使靈敏度降 低，所以在混波器54前加上一隔離器52可降低反射回到混波器54之功率， 故可改善接收裝置的靈敏度。 再者，接收裝置更包含一放大器60、一中頻放大器62與一帶通濾波器 64。放大器60接收過濾訊號，放大過濾訊號並輸出至隔離器52，其中，放 大器60為一低雜訊放大器（Low Noise Amplifier，LNA)。中頻放大器62 接收混波訊號，放大混波訊號並輸出混波訊號，帶通濾波器64接收混波訊 號，過濾混波訊號並輸出混波訊號至增益控制單元56。 綜上所述，本發明之調頻連續波雷達之收發裝置，其發射裝置藉由一 直接數位合成電路本身相雜訊低並線性度佳，再加上鎖相電路與振I電路 而形成一鎖相介質共振振盪器並配合一參考時脈而使調頻連續波雷達輸出 之掃頻連續波訊號具溫度穩定性佳且相雜訊更低。再者，接收裝置藉由一 隔離器以降低反射回到一混波器的功率而改善接收機的靈敏度。 本發明係貫為一具有新穎性、進步性及可供產業利用者，應符合我國 專利法所規定之專利申請要件無疑，爰依法提出發明專利申請，祈鈞局 早曰賜准專利，至感為禱。 惟以上所述者，僅為本發明之一較佳實施例而已，並非用來限定本發 明實施之範圍，舉凡依本發明申請專利範圍所述之形狀、構造、特徵及精 神所為之均等變化與修飾，均應包括於本發明之申請專利範圍内。 【圖式簡單說明】 第一A圖為習知技術之調頻連續波雷達發射波與反射波之調頻曲線圖； 第-B圖為習知技術之調頻連續波雷達發射波與反紐之差頻的曲線圖； 第二圖為本發明之一較佳實施例之發射裝置之方塊圖；以及 第二圖為本發明之一較佳實施例之接收裝置之方塊圖。 200848766 【主要元件符號說明】 10 直接數位合成電路 12 訊號產生電路 14 混波器 16 濾波器 18 訊號分離器 20 鎖相電路 22 振盪電路 30 倍頻器 32 倍頻器 34 除頻器 40 放大器 42 低通濾波器 44 放大器 46 功率放大器 50 濾波器 52 隔離器 54 混波器 56 增益控制單元 60 放大器 62 中頻放大器 64 帶通濾波器= Referring to Figure 2, a block diagram of a receiving device in accordance with a preferred embodiment of the present invention. As shown in the figure: The receiving device comprises a filter 5 〇, an isolation (four) 52, a mixer, 54 and a gain ^ early = 6. The filter 5Q is generated by the frequency-converted continuous wave signal over the lining frequency continuous wave signal, and the isolation device 52 generates the isolated signal according to the sweeping continuous wave signal, that is, the receiving filter 50 filter sweeping continuous wave signal test The filtering and signal are generated to generate the isolation signal. Mixing = 4 flipping the i signal and the _ coffee generating _ output signal, and receiving by the output signal I / shooting ^ output (four) continuous wave signal and the f gain control unit 56 between the swept continuous wave signal received by the receiving device receives The output signal is output to the analog-to-digital conversion circuit (not shown) to convert the output signal to _ digit (4) and back to the gain control unit (4), gain (4) = digital data and control the gain of the signal, so you can borrow From the digital data body, the gain control unit 56 can automatically adjust the gain of the 7056 according to the size of the digital data to improve the dynamic range of the radar price measurement. In the above, since the modulated continuous wave signal is transmitted and received when the continuous wave radar side is modulated, 200848766 and the transmitting frequency is the same as the frequency of the local oscillation signal, the local oscillation signal leaks into the transmitting end of the mixer 54, and the filtering is performed. The signal reflected by the device 50 is mixed with the local oscillation signal in the mixer 54 to generate a large DC and low frequency output, thereby causing the noise of the receiving device to rise and the sensitivity to be lowered. Therefore, a mixer is added in front of the mixer 54. The isolator 52 reduces the power reflected back to the mixer 54, thereby improving the sensitivity of the receiving device. Furthermore, the receiving device further includes an amplifier 60, an intermediate frequency amplifier 62 and a band pass filter 64. The amplifier 60 receives the filtered signal, amplifies the filtered signal and outputs it to the isolator 52, wherein the amplifier 60 is a Low Noise Amplifier (LNA). The intermediate frequency amplifier 62 receives the mixed signal, amplifies the mixed signal and outputs the mixed signal, the band pass filter 64 receives the mixed signal, filters the mixed signal, and outputs the mixed signal to the gain control unit 56. In summary, the transmitting and receiving device of the frequency modulated continuous wave radar of the present invention has a low noise and good linearity by a direct digital synthesizing circuit itself, and a locking circuit and a vibration I circuit form a lock. The phase medium resonant oscillator is combined with a reference clock to make the frequency-converted continuous wave signal of the FM continuous wave radar output have good temperature stability and lower phase noise. Furthermore, the receiving device improves the sensitivity of the receiver by means of an isolator to reduce the power reflected back to a mixer. The invention is a novel, progressive and available for industrial use, and should meet the requirements of the patent application stipulated in the Patent Law of China, and the invention patent application is filed according to law, and the prayer bureau gives the patent as early as possible. For prayer. However, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the shapes, structures, features, and spirits described in the claims are equivalently changed. Modifications are intended to be included in the scope of the patent application of the present invention. [Simple description of the diagram] The first A picture is the frequency modulation curve of the transmitted wave and the reflected wave of the frequency modulated continuous wave radar of the prior art; the first picture B is the difference frequency of the transmitted wave and the anti-new line of the frequency modulated continuous wave radar of the prior art. 2 is a block diagram of a transmitting device in accordance with a preferred embodiment of the present invention; and a second block is a block diagram of a receiving device in accordance with a preferred embodiment of the present invention. 200848766 [Description of main component symbols] 10 Direct digital synthesizing circuit 12 Signal generating circuit 14 Mixer 16 Filter 18 Signal splitter 20 Phase lock circuit 22 Oscillation circuit 30 Multiplier 32 Multiplier 34 Frequency divider 40 Amplifier 42 Low Pass Filter 44 Amplifier 46 Power Amplifier 50 Filter 52 Isolator 54 Mixer 56 Gain Control Unit 60 Amplifier 62 IF Amplifier 64 Bandpass Filter