進齊邛智慧財產局員工消費合作社印製 536911 五、發明說明（/ ) 本發明是有關於一種影像抑制接收器，且特別是有關 於一種使用多重低中介頻率接收器與零中介頻率轉換接收 器的影像抑制接收器。 在影像抑制接收器（image reject receiver)的架構中，單 一中介頻率接收器（single-intermediate Frequency receiver，single-I.F. receiver)與多重低中介頻率接收器 (multi-Intermediate Frequency receiver ? multi-I.F. receiver) 架構已經使用了許多年。在這些架構下，每一層中介頻率 階段（Intermediate Frequency stage，I.F. stage)爲了抑制影像 頻率，都必須使用大量且昂貴的瀘波器(filter*)。而爲了將中 介頻率濾波器的Q値保持在一個理想値之內，就必須使接 收到的射頻（Radio Frequency，RF)與中介頻率間的比値降 低。面對現今環境中越來越高的射頻操作頻率，爲了能在 將接收到的影像訊號降頻到容易解調（demodulation)的同 時，也能使中介頻率濾波器的Q値保持在某個理想値之 內，就必須使用越來越多層的中介頻率階段。而隨著中介 頻率階段的增多，所需要的中介頻率濾波器元件也會增 多。 因此，習知技術就採用了零中介頻率接收器（zero-I.F. receiver)的架構，以解決由單一中介頻率接收器與多重低中 介頻率接收器架構所衍生出來的問題。然而，零中介頻率 接收器爲了解調，卻必須使用大量且昂貴的類比數位轉換 器（Analog/Digital Converter，A/D Converter)，而且還遭遇 到許多的問題，例如：由不協調阻抗匹配所造成的寄生直 3 -----！丨—訂·丨！ ！！ *^ IAWI (請先閱讀背面之注意事項再填寫本頁) 本紙張尺度適用中國國家標準（CNS)Al規格（210 x 297公餐） 經濟部智慧財產局員工消費合作社印製 536911 五、發明說明（V) 流訊號，局部震盪器自我混雜（self_mixing)與再輻射（re_ radiation)，以及阻礙所想要之訊號的射頻交越干擾（cross talk)等。 此外，零中介頻率接收器還會產生微弱而非需要的基 頻訊號(baseband signal)。這種微弱的基頻訊號在變動狀態 量多的情況下，是很難來加以處裡的。因此，爲了達到精 密應用時所需的處理結果’ A/D轉換器就必須具有特殊的 線性低噪音放大器（l〇w-n〇ise amplifier，LNA)與混頻器 (mixer)，極佳的獨立區域震擾(Local Oscillator，L0)訊號， 以及消除微伏直流偏移（microvolt D.C. offset)的方法。然 而，這些限制卻很難同時解決。 綜上所述，習知的技術中有數種缺點，現列述如下： 1. 在單一中介頻率接收器與多重低中介頻率接收器架 構下，隨著射頻操作頻率越來越高就必須使用越來越多層 的中介頻率階段，而隨著中介頻率階段的增多，所需要的 中介頻率濾波器元件也會增多； 2. 零中介頻率接收器爲了解調，必須使用大量且昂貴的 類比數位轉換器，而且還遭遇到如：由不協調阻抗匹配所 造成的直流訊號，局部震盪器自我混雜與再輻射，以及阻 礙所想要之訊號的射頻交越干擾等問題；以及 3. 零中介頻率接收器中的A/D轉換器必須具有特殊的 線性低噪音放大器與混頻器’極佳的獨立L0訊號，以及消 除微伏直流偏移的方法，然而這些限制卻很難可以同時達 成。 4 本紙張尺度適用中國國^準（CNS)A4規格⑵0 X 297 & ) ' " (請先閱讀背面之注意事項再填寫本頁)Printed by the Consumer Property Cooperative of the Intellectual Property Bureau of the People's Republic of China printed 536911 V. Description of the invention (/) The present invention relates to an image suppression receiver, and in particular to a method using multiple low-intermediate frequency receivers and zero-intermediate frequency conversion receivers Image suppression receiver. In the architecture of an image reject receiver, a single-intermediate frequency receiver (single-IF receiver) and a multiple low-intermediate frequency receiver (multi-IF receiver) The architecture has been used for many years. Under these architectures, in order to suppress the image frequency at each intermediate frequency stage (I.F. stage), a large number and expensive filters * must be used. In order to keep the Q 値 of the intermediate frequency filter within an ideal 値, the ratio 値 between the received radio frequency (RF) and the intermediate frequency must be reduced. Facing the increasingly high RF operating frequency in today's environment, in order to reduce the frequency of the received image signal to easy demodulation, the Q 値 of the intermediate frequency filter can also be maintained at an ideal level. Within that, more and more layers of intermediate frequency stages must be used. As the number of intermediate frequency stages increases, more intermediate frequency filter components are required. Therefore, the conventional technology uses a zero-I.F. Receiver architecture to solve the problems derived from a single intermediate frequency receiver and multiple low-intermediate frequency receiver architectures. However, in order to demodulate a zero-intermediate frequency receiver, it must use a large number of expensive analog / digital converters (A / D Converters), and it also encounters many problems, such as being caused by uncoordinated impedance matching. Caused by parasitic straight 3 -----!丨 —Order · 丨! !! !! * ^ IAWI (Please read the notes on the back before filling in this page) This paper size is applicable to Chinese National Standard (CNS) Al specification (210 x 297 meals) Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs Consumer Cooperatives 536911 V. Description of the invention (V) Streaming signals, self-mixing and re-radiation of local oscillators, and radio frequency cross talk that obstructs desired signals. In addition, zero intermediate frequency receivers can generate weak but not needed baseband signals. This kind of weak baseband signal is difficult to deal with when there are many changes in the state. Therefore, in order to achieve the processing results required for precision applications, the A / D converter must have a special linear low-noise amplifier (LNA) and a mixer, which are excellent independent areas. Local Oscillator (L0) signal, and method for eliminating microvolt DC offset. However, these limitations are difficult to address at the same time. In summary, there are several shortcomings in the conventional technology, which are listed as follows: 1. Under the architecture of a single intermediate frequency receiver and multiple low intermediate frequency receivers, as the operating frequency of the RF becomes higher and higher, it must be used. There are more and more layers of intermediate frequency stages, and as the intermediate frequency stages increase, the required intermediate frequency filter components will also increase; 2. In order to demodulate a zero intermediate frequency receiver, a large number of expensive analog digital converters must be used , And also encountered problems such as: DC signals caused by uncoordinated impedance matching, self-mixing and re-radiation of local oscillators, and RF crossover interference that hindered the desired signal; and 3. Zero-intermediate frequency receiver The A / D converter must have a special linear low-noise amplifier and mixer's excellent independent L0 signal and a method to eliminate microvolt DC offset. However, these limitations are difficult to achieve at the same time. 4 This paper size is applicable to China National Standard (CNS) A4 size 0 X 297 &) '" (Please read the precautions on the back before filling this page)
•線- 536911• line-536911
五、發明說明（、） 經濟部智慧財產局員工消費合作社印製 有鑒於此，本發明提出一種使用多重低中介頻率與零 中介頻率轉換接收器的影像抑制接收器。本發明所提供的 影像抑制接收器包括一個第一低中介頻率接收器，一個零 中介頻率轉換接收器，以及一個第二低中介頻率接收器。 其中，第一低中介頻率接收器係用以接收影像訊號，並將 此影像訊號以此第一低中介頻率接收器所使用的第一中介 頻率爲載波，而成爲一個映射影像訊號。之後，此映射影 像訊號被傳送到零中介頻率轉換接收器之中。零中介頻率 轉換接收器在接收此以第一中介頻率爲載波的映射影像訊 號後，就將位於第一中介頻率上的映射影像訊號抑制 (suppress)到零頻上。最後，第二低中介頻率接收器就接收 經零中介頻率轉換接收器抑制後的映射影像訊號，並將此 抑制後的映射影像訊號以第二低中介頻率接收器所使用的 第二中介頻率爲載波，以利於解調此抑制後的映射影像訊 號。 此外，本發明還可以利用一個直流校正電路，以將由 零中介頻率轉換接收器所產生的直流偏壓加以消除。其 中，此直流校正電路係位於零中介頻率轉換接收器之中。 綜上所述，本發明藉由依照順序結合第一低中介頻率 接收器，零中介頻率轉換接收器與第二低中介頻率接收 器，首先於第一低中介頻率接收器中，僅將影像訊號置放 在低頻的中介頻率（第一中介頻率）上。而抑制影像訊號的工 作則由零中介頻率轉換接收器加以進行。最後，再將經抑 制後所得的影像訊號經過第二低中介頻率接收器，使得載 ———·丨丨 (請先閱讀背面之注意事項再填寫本頁) 訂· · •線· 536911 Λ7 B7 5925twf-doc/〇〇9 五、發明說明（今） 波上升到一定的頻率（第二中介頻率），以利於影像訊號的解 調操作之進行。 ------------裝·丨I (請先閱讀背面之注意事項再填寫本頁) 爲讓本發明之上述和其他目的、特徵、和優點能更明 顯易懂’下文特舉較佳實施例，並配合所附圖式，作詳細 說明如下： •圖式之簡單說明： 第1圖繪示的是根據本發明之一較佳實施例的影像抑 制接收器內部系統連結方塊圖；以及 第2圖繪示的是根據本發明之另一較佳實施例的電路 圖。 重要元件標號 _ 100，200 :影像抑制接收器 110，130，210，230 :低中介頻率接收器 12〇 ’ 220 :零中介頻率轉換接收器 212 :低噪音線性放大器 線· 214A，214B，222A，222B，222C，222D，234A，234B : 混頻器 216A，216B，224A，224B :低通濾波器 經濟部智慧財產局員工消費合作社印製 218A ’ 218B，219A，219B，226A，226B，236A，236B ·· 放大器 223A :加法器 223B :減法器 240 :解調器 25〇，255 :直流校正電路 6 關表標準（CNSM !規格⑵0 X 297公爱 536911 經濟邹智慧財產局員工消費合作社印製 五、發明說明（哆） 260 ··合成器 丰實施例 請參照第1圖，其繪示的是依照本發明一較佳實施例的 影像抑制接收器內部系統連結方塊圖。其中，影像抑制接 收器(image reject receiver)100之中包括兩個低中介頻率接 收器（Low-Intermediate Frequency receiver)l 10與 130， 以及 一個零中介頻率轉換接收器（Zero-Intermediate Frequency conversion receiver) 120。低中介頻率接收器110(或稱第一低 中介頻率接收器）以一個中介頻率（後稱第一中介頻率）爲操 作時所使用的載波。此低中介頻率接收器110從外界接收一 個影像訊號，並將此影像訊號轉換爲以第一中介頻率爲載 波的映射影像訊號。 在影像訊號被轉換爲以第一中介頻率爲載波的映射影 像訊號之後，零中介頻率轉換接收器120就接收此以第一中 介頻率爲載波的映射影像訊號，並將此映射影像訊號抑制 到零頻上。而低中介頻率接收器130(或稱第二低中介頻率 接收器）則使用另一個中介頻率（後稱第二中介頻率）以做爲 操作時所使用的載波，並於映射影像訊號被抑制到零頻之 後，接收此經抑制的映射影像訊號，並將此經抑制的映射 影像訊號的載波上轉到第二中介頻率上。最後，再將此以 第二中介頻率爲載波的映射影像訊號加以解調。 接下來請參照第2圖，其顯示的是根據本發明之另一較 佳實施例的電路圖。在影像抑制接收器200之中，除了兩個 低中介頻率接收器210與230，以及一個零中介頻率轉換接 7 (請先閱讀背面之注意事項再填寫本頁) * -·1111111 ·111111. 線 « 本紙張尺度適用中國國家標準（CNS)A·〗規格（210 X 297公釐） 536911 經濟部智慧財產局員工消費合作社印製 五、發明說明（u) 收器220之外，還包括了一個解調器240。此外，在零中介 頻率轉換接收器220之中，還包括了直流校正電路250與 255 ° 影像訊號在傳進低中介頻率接收器210(第一低中介頻 率接收器）時，會先經過一個線性低噪音放大器（low-noise amplifier，LNA)212，以將影像訊號在最不受外界環境影響 的狀況下加以放大。之後，再藉由混頻器（Mixer)214A與 214B，將低中介頻率接收器210所使用的中介頻率（第一中 介頻率）整合到影像訊號之中。其中，第一中介頻率係以區 域震盪訊號之頻率爲依據所產生，而此區域震盪訊號則是 由可以產生震盪訊號的合成器（synthesizer)260所產生。之 後，影像訊號分別透過低通濾波器(LowPassFnterPMA與 216B，以及放大器（amplifier)218A與218B，將原本高頻的 影像訊號轉換成以第一中介頻率爲載波的映射影像訊號。 這個由高頻轉換爲低頻的操作，由於區域震盪訊號（LO signal)與影像訊號的頻率不同，因此可以減少區域震盪訊號 再輻射(reradiation)進入接收天線的可能性。而這種再輻射 的可能性，就是僅使用零中介頻率轉換接收器時的一個缺 點。由此可知，減少再輻射就是本影像抑制接收器比習知 的接收器架構更爲優良的其中一個理由。 接下來，由低中介頻率接收器210所產生的映射影像訊 號就會傳入零中介頻率轉換接收器220之中。兩組映射影像 訊號在經過混頻器222A，222B與混頻器222C，222D而與區 域震盪訊號混頻之後，其中一組映射影像訊號就經過加法 8 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公髮) ~ ~" (請先閱讀背面之注意事項再填寫本頁) 4 ·. ，線. 536911 五、發明說明（' ) (請先閱讀背面之注意事項再填寫本頁) 器223A，低通濾波器224A以及放大器226A而生成一組經抑 制（suppressed)後所得的映射影像訊號。而另外一組的映射 影像訊號在經過減法器223B，低通濾波器224B以及放大器 226B之後，則會生成另一組經抑制後所得的映射影像訊 號。而直流校正電路250與255，則分別用以消除這兩組經 抑制後所得的映射影像訊號中所包括的微伏直流偏移 (microvolt D.C. offset)。 這兩組經過抑制後所得的映射影像訊號’在進入低中 介頻率接收器230(第二低中介頻率接收器）之後，就分別經 過混頻器234A與234B，與此低中介頻率接收器230所使用的 中介頻率（第二中介頻率）相互混頻。接下來’在將兩組映射 影像訊號相加後，把相加所得的映射影像訊號輸出至解調 器240中加以解調。 經濟部智慧財產局員工消費合作社印製 必須注意的是，合成器260除了提供低中介頻率接收器 210所使用的區域震盪訊號之外，也經過除法器232、228A 及228B，分別提供零中介頻率轉換接收器220與低中介頻率 接收器230所使用的區域震盪訊號。而雖然在此處的除法器 232是除以常數4，而除法器228A與228B則是除以常數2，但 並不表示所除的常數必須以此爲限。 此外，由於低中介頻率接收器210所使用的是低頻的中 介頻率，因此在低中介頻率接收器210與零中介頻率轉換接 收器220之間的阻抗匹配（match)就可以更容易做得比以前 高頻的時候更好。而隨著阻抗匹配性的改良，整個影像抑 制接收器的效果就可以更好。而且由於低頻的關係，零中 9 本紙張尺^刺巾關家鮮（CNSM·丨舰（210 X 297公爱) _~^ 536911 五、發明說明（¾ ) 介頻率轉換接收器220與低中介頻率接收器230的區域震盪 訊號，就可以由合成器260經過簡易的除法電路來產生，而 不需要複雜的高頻訊號產生電路。 再者，由於影像的抑制（suppress)是在零中介頻率轉換 接收器之中進行，因此低中介頻率接收器210中的濾波器數 量及操作成果(performance)就與影像訊號頻率（或稱射頻操 作頻率，Radiation Frequency)與中介頻率之間的比値相關 度就會減低。在這種條件下，就可以較習知相對的降低低 中介頻率接收器210中的濾波器數量。 綜上所述，現將本發明的優點略述如下。本發明可以 減少區域震盪訊號再輻射進入接收天線的可能性，且可以 簡單的除法電路取代複雜的高頻訊號產生電路。此外’由 於阻抗匹配的改良，所以其操作成果會更爲良好。而所需 濾波器的數量及品質限制都可以大幅的降低。 雖然本發明已以較佳實施例揭露如上，然其並非用以 限定本發明，任何熟習此技藝者，在不脫離本發明之精神 和範圍內，當可作各種之更動與潤飾，因此本發明之保護 範圍當視後附之申請專利範圍所界定者爲準。 (請先閱讀背面之注意事項再填寫本頁) HP裝 訂： •線· 經濟部智慧財產局員工消費合作社印製 10 本紙張尺度適用中國國家標準（CNS)Al規格（21〇 x 公髮）V. Description of the invention (,) Printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economics In view of this, the present invention proposes an image suppression receiver using multiple low-intermediate frequency and zero-intermediate frequency conversion receivers. The image suppression receiver provided by the present invention includes a first low-intermediate frequency receiver, a zero-intermediate frequency conversion receiver, and a second low-intermediate frequency receiver. The first low-intermediate frequency receiver is used to receive an image signal, and the image signal is a carrier image using the first intermediate frequency used by the first low-intermediate frequency receiver as a mapped image signal. The mapped image signal is then transmitted to a zero-intermediate frequency conversion receiver. After receiving the mapped image signal with the first intermediate frequency as a carrier, the zero intermediate frequency conversion receiver suppresses the mapped image signal at the first intermediate frequency to zero frequency. Finally, the second low-intermediate frequency receiver receives the mapped image signal suppressed by the zero-intermediate frequency conversion receiver, and uses the second intermediate-media frequency used by the second low-intermediate frequency receiver as Carrier to facilitate demodulation of this suppressed mapped image signal. In addition, the present invention can use a DC correction circuit to eliminate the DC bias generated by the zero-intermediate frequency conversion receiver. Among them, the DC correction circuit is located in a zero-intermediate frequency conversion receiver. In summary, the present invention combines the first low-intermediate frequency receiver, the zero-intermediate frequency conversion receiver and the second low-intermediate frequency receiver in order. Firstly, in the first low-intermediate frequency receiver, only the video signal is transmitted. Place on the low-frequency intermediate frequency (first intermediate frequency). The suppression of the image signal is performed by a zero-intermediate frequency conversion receiver. Finally, the image signal obtained after the suppression is passed through the second low-intermediate frequency receiver, so that the load ——— · 丨 丨 (Please read the precautions on the back before filling in this page) Order · · • Line · 536911 Λ7 B7 5925twf-doc / 〇〇9 V. Description of the invention (today) The wave rises to a certain frequency (second intermediate frequency) to facilitate the demodulation operation of the image signal. ------------ Installation I (Please read the precautions on the back before filling out this page) In order to make the above and other objects, features, and advantages of the present invention more obvious and easy to understand 'below The preferred embodiment is described in detail with the accompanying drawings as follows: • Brief description of the drawings: Figure 1 shows the internal system connection of the image suppression receiver according to a preferred embodiment of the present invention. A block diagram; and FIG. 2 shows a circuit diagram according to another preferred embodiment of the present invention. Signs of important components _ 100, 200: image suppression receivers 110, 130, 210, 230: low-intermediate frequency receiver 120 ′ 220: zero-intermediate frequency conversion receiver 212: low-noise linear amplifier line · 214A, 214B, 222A, 222B, 222C, 222D, 234A, 234B: Mixers 216A, 216B, 224A, 224B: Low-pass filter Printed by the Consumer Property Cooperative of the Intellectual Property Bureau of the Ministry of Economy 218A '218B, 219A, 219B, 226A, 226B, 236A, 236B ·· Amplifier 223A: Adder 223B: Subtractor 240: Demodulator 25〇, 255: DC correction circuit 6 Off-meter standard (CNSM! Specification ⑵ 0 X 297 Public Love 536911 Economy Zou Intellectual Property Bureau Employee Consumer Cooperative Printed Description of the invention (哆) 260. The embodiment of the synthesizer please refer to FIG. 1, which shows a block diagram of the internal system connection of the image suppression receiver according to a preferred embodiment of the present invention. Among them, the image suppression receiver ( image reject receiver) 100 includes two Low-Intermediate Frequency receivers 10 and 130, and a Zero-Intermediate F receiver (Zero-Intermediate F requency conversion receiver) 120. The low-intermediate frequency receiver 110 (or first low-intermediate frequency receiver) operates with an intermediate frequency (hereinafter referred to as the first intermediate frequency) as the carrier. This low-intermediate frequency receiver 110 Receive an image signal from the outside and convert this image signal into a mapped image signal with the first intermediate frequency as the carrier. After the image signal is converted into a mapped image signal with the first intermediate frequency as the carrier, zero intermediate frequency conversion is received. The receiver 120 receives the mapped image signal with the first intermediate frequency as a carrier, and suppresses the mapped image signal to zero frequency. The low intermediate frequency receiver 130 (or the second low intermediate frequency receiver) uses another An intermediate frequency (hereinafter referred to as a second intermediate frequency) is used as a carrier for operation, and after the mapped image signal is suppressed to zero frequency, the suppressed mapped image signal is received, and the suppressed mapped image is received. The carrier of the signal is transferred to the second intermediate frequency. Finally, the mapped image signal with the second intermediate frequency as the carrier is added. Demodulation. Next, please refer to FIG. 2, which shows a circuit diagram according to another preferred embodiment of the present invention. In the image suppression receiver 200, except for two low-intermediate frequency receivers 210 and 230, and A zero-intermediate frequency conversion connector 7 (Please read the precautions on the back before filling out this page) *-· 1111111 · 111111. Line «This paper size applies to China National Standard (CNS) A ·〗 Specifications (210 X 297 mm) 536911 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the Invention (u) In addition to the receiver 220, a demodulator 240 is included. In addition, the zero-intermediate frequency conversion receiver 220 also includes DC correction circuits 250 and 255 °. When the image signal is transmitted to the low-intermediate frequency receiver 210 (the first low-intermediate frequency receiver), it first passes a linear A low-noise amplifier (LNA) 212 is used to amplify the image signal under the conditions that are least affected by the external environment. After that, the intermediate frequency (the first intermediate frequency) used by the low intermediate frequency receiver 210 is integrated into the image signal through the mixers 214A and 214B. Among them, the first intermediate frequency is generated based on the frequency of the regional oscillating signal, and the regional oscillating signal is generated by a synthesizer 260 that can generate the oscillating signal. After that, the image signal is converted into the image signal with the first intermediate frequency as the carrier through the low-frequency filters (LowPassFnterPMA and 216B, and the amplifiers 218A and 218B, respectively). For low-frequency operation, because the frequency of the local oscillation signal (LO signal) is different from the image signal, the possibility of reradiation of the local oscillation signal into the receiving antenna can be reduced. The possibility of this re-radiation is to use only A disadvantage of the zero-intermediate frequency conversion receiver. From this, it can be seen that reducing re-radiation is one of the reasons why this image suppression receiver is better than the conventional receiver architecture. Next, the low-intermediate frequency receiver 210 The generated mapped image signal is transmitted to the zero-intermediate frequency conversion receiver 220. After the two mapped image signals pass through mixers 222A, 222B and mixers 222C, 222D, and are mixed with the regional oscillating signal, one of them The group mapping image signal is added. 8 This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 29 7 public hair) ~ ~ " (Please read the precautions on the back before filling out this page) 4 ·., Line. 536911 V. Invention description (') (Please read the precautions on the back before filling out this page) 223A , The low-pass filter 224A and the amplifier 226A generate a set of suppressed image signals obtained after suppression. The other set of mapped image signals passes through the subtractor 223B, the low-pass filter 224B, and the amplifier 226B. Will generate another set of suppressed mapped image signals. DC correction circuits 250 and 255, respectively, are used to eliminate the microvolt DC offset (microvolt DC) included in these two sets of suppressed mapped image signals. offset). After these two sets of mapped image signals obtained after suppression enter low-intermediate frequency receiver 230 (second low-intermediate frequency receiver), they pass through mixers 234A and 234B, respectively, and receive with this low-intermediate frequency. The intermediate frequency (second intermediate frequency) used by the mixer 230 is mixed with each other. Next, after adding the two sets of mapped image signals, the mapped image signals obtained by the addition are output to the solution. The demodulator 240 is demodulated. It must be noted that the consumer property cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs prints that the synthesizer 260 passes the divider 232, 228A and 228B, which provides the regional oscillating signal used by the zero-intermediate frequency conversion receiver 220 and the low-intermediate frequency receiver 230. Although the divider 232 here is divided by a constant 4, the dividers 228A and 228B are divided by The constant 2 does not mean that the constant to be divided must be limited to this. In addition, since the low-intermediate frequency receiver 210 uses a low-intermediate frequency, the impedance match between the low-intermediate frequency receiver 210 and the zero-intermediate frequency conversion receiver 220 can be made easier than before. Better at high frequencies. With the improvement of impedance matching, the effect of the whole image suppression receiver can be better. And because of the low frequency, 9 paper rulers ^ stab towel Guan Jiaxian (CNSM · 丨 ship (210 X 297 public love) _ ~ ^ 536911 V. Description of the invention (¾) Frequency conversion receiver 220 and low intermediate The regional oscillating signal of the frequency receiver 230 can be generated by the synthesizer 260 through a simple division circuit, without the need for a complicated high-frequency signal generating circuit. Furthermore, because the suppression of the image is converted at zero intermediate frequency In the receiver, so the number of filters and operating performance in the low intermediate frequency receiver 210 is related to the ratio of the image signal frequency (or radio frequency) to the intermediate frequency. It will be reduced. Under this condition, the number of filters in the low-intermediate-frequency receiver 210 can be relatively reduced compared to the conventional ones. In summary, the advantages of the present invention are briefly described below. The present invention can reduce regional oscillations The possibility of the signal re-radiating into the receiving antenna, and a simple division circuit can be used to replace the complex high-frequency signal generation circuit. In addition, due to the improved impedance matching, The operation results will be better. The number and quality restrictions of the required filters can be greatly reduced. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technique Without departing from the spirit and scope of the present invention, various modifications and retouching can be made, so the scope of protection of the present invention shall be determined by the scope of the attached patent application. (Please read the notes on the back first (Fill in this page again.) HP Binding: • Line · Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs' Consumer Cooperatives 10 This paper size applies to the Chinese National Standard (CNS) Al specification (21〇x issued)