TWI244864B - Frequency conversion in a receiver - Google Patents

Abstract

A method for frequency conversion of a receiver, including the steps of receiving a signal having a radio frequency and carrying information on a plurality of channels, selecting one of the channels, converting the signal from the radio frequency to a first variable frequency determined by the selected channel, and converting the signal from the first frequency to a desired frequency.

Description

The technical field to which the invention belongs, in particular, relates to a triple frequency reduction method. The present invention is based on a step-by-step conversion method. 2 The radio frequency information in a television tuner is used in the prior art. It is widely used in a variety of consumer or commercial system data. Two L: two projectors or other more Complex electronic equipment, such as cables, etc. There are nearly 300 million broadband tuners in the world every year. Television and cable TV companies provide more and more types of services and their market is developing rapidly. "Tickets" for playing DVDs, video recorders, and mobile phones to a set-top box or a TV set will be the main feature of the Media Center. The tuner is mainly used as a radio frequency front end for broadband signals. The management circuit uses ##: # on f, selects the channel and filters out the signals of other channels: Lei Yan ~ The tuner operates in the frequency range of 40 to 900mhz, and has the same function as the 2-view tuner. Different performance requirements. Small size, low power, high guiltyness and simple manufacturing are the main performance considerations of modern tuners. In TV converters, the frequency conversion method is very important for tuner two. Part 1 The figure shows the single-chip circuit of the highly integrated dual frequency conversion television tuner disclosed in U.S. Patent No. 5,737,035. The RF signal is first received via the antenna 1402 (or cable), and the received signal is received via RF low 1404. The frequency band signal is limited to below 900MHz. The filtered frequency signal is then passed through a gain-controlled low-noise conductance amplifier.

1244864. V. Explanation of invention (2). The first local oscillator 1 450 operates between 1 200 and 2100 MHz. Its output signal is mixed with the RF signal in the first mixer 1 408 to generate a first intermediate frequency signal. The carrier frequency is 1 200 MHz. . Due to the mixing of images and harmonics, this processing method can minimize distortion. The harmonic components of the first IF signal are band-limited by the first mixer 1 0 08, and the 0 intermediate frequency signal (1 200 MHz) is approximately filtered, and then the second mixer 1 41 0 and the second mixer The output signal of the local oscillator 1 4 1 2 is mixed to generate a second intermediate frequency 4 Lu No. 'The second mixer 1 4 1 0 is an image rejection mixer (Image-rejection mixer), the second The output frequency of the local oscillator 1412 is 11 80 MHz, and the carrier frequency of the second intermediate frequency signal is 20 MHz. The input RF signal is lower in frequency than the oscillating signal. In this way, the frequency mixing effect is produced. ° However, in the above-mentioned TV tuner, the radio frequency t-surface acoustic wave filter of the out-of-band signal unit is eliminated, such as: surface acoustic wave driving that requires linearization and energy consumption.

In addition, the circuit used to generate the first mixed ySAW locked loop circuit must add the phase of h-^ 彳 祝 祝 祝 祝 This W ^ 刼 is made at a frequency that also makes the first operation The output noise of Dagger Wave is very serious. In order to solve the above problems, the present invention provides a use; the small number of components and the low power consumption and high signal-to-noise ratio make the first object of the present invention to provide-a frequency for access

= Method 'includes the following steps: receiving multiple channels of radio frequency modulation information; selecting one of the channels; 5: converting radio frequency to a first frequency, the first frequency and the selected channel are determined ; And then spleen q flute 4S ^ according to the rate. And converting the first frequency of δH to the second frequency. A second object of the present invention is to provide a receiver including one time, receiving a radio frequency signal, the signal including a carrier channel;-the first local oscillator, i -Has a J-th oscillating signal and a B-mixer 1 The radio frequency signal is mixed with the first oscillation to generate an intermediate frequency signal; a second local oscillator, which produces a signal having a second frequency A second oscillating signal; and a second mixer, mixing the intermediate frequency signal with the second oscillating signal to generate a base G number, wherein the frequency of the intermediate frequency # number is variable and depends on It depends on the selected channel. A third object of the present invention is to provide a receiver, which includes: an antenna 'receives a radio frequency signal number' far k number contains a plurality of channels carrying modulation information; a first local oscillator 'generates a signal having a A first oscillating signal of a first frequency; a first mixer 'mixes the radio frequency signal with the first oscillating signal to generate a first intermediate frequency signal; a second local oscillator, A second oscillating signal of a second frequency; a second mixer that mixes the first IF signal with the second oscillating signal to generate a second IF signal; / a third local oscillator that generates a A third oscillating signal with a third frequency; a third mixer 'mixes the second intermediate frequency signal with the third oscillating signal to generate a fundamental frequency signal; wherein the first

Page 7 0828-A40107TWF; VINCENT.ptd 1244864 V. Description of the Invention (4) " ~ The frequency of the IF signal is variable and depends on the selected channel. In the following, a receiver according to the present invention and an embodiment of a frequency conversion method used in the receiver will be described in a diagrammatic manner. Embodiment Figure 2 shows a television tuner in an embodiment of the present invention. The TV tuner (receiver) includes an antenna 21, a low noise amplifier 22, a first local oscillator 23, a first mixer 24, a second local oscillator 25, and a first mixed wave. Zhai 26 and a surface acoustic wave driver 27. The antenna 21 receives a radio frequency signal, and the radio frequency signal carries information in all television channels. Low noise amplification ^ § 2 2 Fu is connected to the antenna 21 to amplify the RF signal. The first local oscillator 23 generates a first oscillating signal osi having a frequency F01. The first mixer 24 mixes the amplified RF signal with the first oscillating signal ⑽1 to generate an intermediate frequency signal IS. The second local oscillator 25 generates a second oscillating signal os 2 having a frequency F 0 2. The second mixer 26 mixes the intermediate frequency signal I s with the booster number 0 S 2 'to generate a fundamental frequency signal β §. The surface acoustic wave driver 27 is connected to the output end of the second mixer 26 to drive an external surface acoustic wave filter (not shown). The first local oscillator 23 and the mixer 24 form a first frequency conversion stage, which converts a radio frequency signal from radio frequency to an intermediate frequency I ρ, where the value of the intermediate frequency I F is determined according to the selected channel. The value of the intermediate frequency I ρ is higher than the frequency of the RF signal (upscaling), and its frequency value is determined so as to minimize the amount of noise and false signals coupled from other channels to the selected channel. The value of the intermediate frequency IF varies with the selected channel. The second local oscillator 25 and the mixer 26 form a second frequency conversion stage, which converts the signal from the intermediate frequency

0828-A40107TWF; VINCENT.ptd Page 8 1244864 1. Fifth, the description of the invention (5) ί 2 = 2, ί: (Like rejection and rejection) :: J frequency is the same for all channels. The aliasing is eliminated. Frequency build mLc tank, the figure is not shown) The second electric brother 3 can not display the oscillator 23, and its package 231, phase frequency detector 232, 口, ^, ^: normal state 234, electric 嶋 j_, 235, = f33, The loop wave generator weeping 9 to 7 potential Yingjie first frequency divider 236 and frequency multiplication state 237. Brother one frequency divider

Divide by a child fW, and consider the reference frequency FR divisor N of h. The phase frequency detector 232 has a first output from the first shuttle to the first frequency divider 231. The output of the f 妾 terminal is coupled to the phase frequency detection number 2 ^ at ψ ^ Pu 233 with an input right one ridge. λ * mount, output. The loop filter 234 has a write 235 # and is provided at the output terminal of the electric power pump 233. The electric control oscillator 235 has an input terminal coupled to the output terminal of the loop filter 234. Two frequencies: = 236 divides one from the voltage-controlled oscillator by-divisor P to output the first vibration surplus message i frequency sheep

The first oscillating signal 0S1 is multiplied by an automatic M and the I-bit frequency detector 232 ^ the J-th input terminal and tv, and the values of the phase, ^ Leyi input and M are determined by the selected channel = channel. The frequency F1 of the first oscillating signal 0sl is obtained by the following formula: foi = fr * m / (p * n) FIG. 4 shows a television tuner in another embodiment of the present invention, which uses a double The frequency conversion includes an antenna 41, a low-noise amplifier 42, a first local oscillator 43, a first mixer 44, a second local oscillator 45, a second mixer 46, a Three local oscillators 4 7. Third mixer page 9 0828-A40107TWF; VINCENT, ptd 1244864-V. Description of the invention (6) 4 8 and a surface acoustic wave driver 49. The antenna 41 receives a radio frequency signal, and the radio frequency signal carries information in all television channels. The low-noise amplifier 4 2 is coupled to the antenna 41 to amplify the RF signal. The first local oscillator 43 generates a first oscillation signal OS1 with a frequency of F01. The first mixer 44 mixes the amplified radio frequency signal with the first exhausted signal 0 S1 to generate a first intermediate frequency signal IS1. The second local oscillator 45 generates a second oscillation signal OS2 with a frequency of F02. The second mixer 46 mixes the first intermediate frequency signal IS1 and the oscillation signal OS2 to generate a second intermediate frequency signal IS2. The third local oscillator 47 generates a third oscillation signal os3 with a frequency of F03. The third mixer 48 mixes the second intermediate frequency signal IS2 and the oscillation signal 0S3 to generate a basic frequency signal BS. The surface acoustic wave driver 49 is coupled to the output terminal of the third mixer 48, and is used to drive an external surface acoustic wave filter (not shown). The first local oscillator 43 and the mixer 44 form a first frequency conversion stage to convert a radio frequency signal from radio frequency to a first intermediate frequency F1, where the value of the intermediate frequency I F 1 is determined according to the selected channel. Is the value of the intermediate frequency I F 1 local to the radio frequency? The frequency of the tiger (ascending frequency), and its frequency value is determined to minimize the amount of noise and false signal coupling from other channels to the selected channel. The value of the intermediate frequency IF1 will vary depending on the selected channel. Here, the second local oscillator 45 and the mixer 46 form a second frequency conversion stage, which converts the signal from the first intermediate frequency to the second intermediate frequency (down frequency), and its value is the same for all channels. The third local oscillator 47 and the mixer 48 form a second frequency conversion stage 'to convert the first intermediate frequency of the No. 5 band to the fundamental frequency (down frequency). Mixers 4 4, 4, 6 and 4 8 are image rejection mixers, which can eliminate noise caused by the image frequency in the frequency band. Out-of-band signal

1244864 '------------- V. Description of the invention (7) Inductor-capacitor in 46 and 48 (LC tank' not shown) can be used for each oscillator This is the circuit shown in Figure 3. ♦ Rush—After being selected, the values of N, P & M are determined. Tianmou—Frequency This makes ΚΠί, the triple frequency conversion tuning shown in Figure 4 uses two mixers to complete the conversion from wideband to narrowband white, and the second evening $% 7 and frequency The revolution was reduced to phase π: Yi used only a mixer to achieve the function of phase 冋. ^ π As mentioned above, the present invention provides a television tuner with fewer components. In particular, compared with US Patent No. 5,737 彳 -0 and lower, the TV tuner of the present invention has no need to use a meter ~ / rate consumption "Surface acoustic wave driver is eliminated, thus reducing power, although the present invention has been compared with The best embodiment is disclosed above, and Randou #k is used to limit the present invention. Anyone skilled in this art will not depart from :; the god and the range β, when it can be changed here, ㈣ 2 depart from the scope of the present invention. § The appended application patents shall prevail.

1244864_ I Schematic description Figure 1 shows a traditional TV tuner; Figure 2 shows a TV tuner in an embodiment of the invention; Figure 3 shows an oscillator used by a TV tuner in an embodiment of the invention Figure 4 shows a television tuner in another embodiment of the present invention. Explanation of symbols 1 4 0 2, 2 1, 4 antenna; 1 4 0 4 ~ low-pass filter; 1 4 0 6 ~ conductance amplifier; 1 450, 1412, 23, 25, 43, 45, 47 ~ local oscillator 1408, 1410, 24, 26, 44, 46, 48 ~ mixer; 22,42 ~ low noise amplifier; 27,49 ~ surface acoustic wave driver; 2 3 1, 2 3 6 ~ frequency divider; 2 3 2 ~ phase frequency detector; 233 ~ charge pump; 2 3 4 ~ loop filter; 2 3 5 ~ voltage controlled oscillator; 2 3 7 ~ frequency multiplier.

0828-A40107IW; VINCENT.ptd Page 12

Claims (1)

1244864 / 、 The patent application scope is as follows: 1. A method for frequency conversion in a receiver, including the following steps: channel receiving-transmitting 'the signal contains multiple choices of one of the channels carrying modulation information; The radio frequency conversion of the signal is a first change and is determined according to the selected channel; the first frequency can be converted to the second frequency by using the frequency of the second. Conversion of 2 parties; Shen: == 1 Soap description; At the receiver ... Selected channel; of ;; From other channels ... 3 · Frequency conversion in the receiver as described in item 1 of Shengu's patent scope The method, wherein the first frequency is higher than the radio frequency. 4. The method for frequency conversion in a receiver as described in item 丨 of the patent application range, wherein the second frequency is the same for any selected channel. 5. The frequency conversion method for use in a receiver as described in item 1 of the patent application range, wherein the second frequency is a fundamental frequency. 6. The method for frequency conversion in a receiver according to item 1 of the scope of the patent application, further comprising the following steps: Reconverting the second frequency to a second frequency. 7 · The method of frequency conversion for use in a receiver as described in item 6 of the scope of patent application, wherein the determination of the first frequency is made to be switched from other channels to 8 · The channel is selected as of area 6 of the patent application The amount of noise and spurious signals is the smallest. The frequency used in the receiver 0828-A40107TWF; VINCENT. P t d A conversion method, wherein the first frequency is higher than the radio frequency. 9 · The frequency used in the receiver as described in item 6 of the scope of patent application; a conversion method, wherein the second frequency is the same for any selected channel 岣 · as described in item 6 of the scope of patent application Used in the receiver. A conversion method, wherein the second frequency is lower than the first frequency. 、, i 1 · As described in item 6 of the scope of patent application, this conversion method is used in the receiver '/, the third frequency is the same for any selected channel, 1 2 · as the scope of patent application No. 6 The frequency conversion method used in the receiver according to the item, wherein the third frequency is a fundamental frequency. 13. A kind of receiver, including: an antenna 'receives a radio frequency signal, the signal contains a plurality of channels carrying modulation and modulation information; a first local oscillator, which has a first frequency The first ^ a vibration violation signal; a first mixer that mixes the radio frequency signal with the first oscillation signal to generate an intermediate frequency signal; a second local oscillator that generates a second frequency A second exhaustion signal; and a second mixer that mixes the intermediate frequency signal with the second oscillating signal to generate a fundamental frequency signal; wherein the frequency of the intermediate frequency signal is changed in accordance with It depends on the selected channel. 1 4 · The receiver according to item 13 of the scope of patent application ’, wherein the determination of the frequency of the intermediate frequency signal is such that it can be switched from other channels to the selected channel. 0828-A40107TWF; VINCENT. Ptd page 14 15. The patented patented oscillator includes: the receiver described in item d, wherein the-^ 土 a chip character ^ 'in the -U reference signal reference frequency FR Divide by six. The minimum noise and false signal amount in the patent application range. The first frequency divider is a divisor N; °° is a phase frequency detector and the output of the frequency divider; ^ has a first input terminal coupled The input terminal of the first round is coupled to the output terminal of a charge pump of the phase frequency detector; a loop filter has an output terminal; the input terminal is coupled to the charge pump! A voltage-controlled oscillator, the output terminal of the device; "an input terminal is coupled to the loop to filter a second frequency divided by the frequency of the number divided by a divisor P and the wheel 'will send a signal from the voltage-controlled oscillator A-frequency multiplier, the second one, the oscillating signal; and two Λs connected to the second input terminal of the phase frequency detector and expressing M r • A receiver as described in item 15 of the patent scope The sending N and M are determined by the selected channel. The receiver of N, P 1 feet is the receiver described in item i 3 of the scope of patent application, and a low noise amplifier is coupled to the antenna and The first mixer is used to amplify the radio frequency signal. ° 拜 '18 1 The receiver as described in the scope of patent application No. 丨 3, wherein a surface acoustic wave driver (SAW driver) is connected to the receiver. Second, Japanese, Japanese, Shishiguo 0828-A40107IW; VINCENT, ptd page 15Ϊ244864, the scope of the patent application for a round of creep. — And \ 9 • The receiver according to item 13 of the patent scope, where the The first mixing wave is an image rejection mixer (imagerejecti ο η mixer) o 2 0 · — a receiver, comprising: an antenna 'receives a radio frequency signal, the signal contains a plurality of channels carrying modulation and modulation resources; a first local oscillator, generating a first having a first frequency Vibration surplus signal; ^ a first mixer that mixes the radio frequency signal with the first oscillating signal to generate a first intermediate frequency signal; a second local oscillator that generates a first Two oscillating signals; ~ a second mixer that mixes the first IF signal with the second oscillating to generate a second IF signal; say a third local oscillator, generating a A third oscillating signal with a third frequency; a third mixer that mixes the second intermediate frequency signal with the third oscillating signal to generate a fundamental frequency signal; ~ wherein the first intermediate frequency signal The frequency is variable and determined according to the selected channel. 2 1 · The receiver as described in item 20 of the patent application scope, wherein the determination of the frequency of the first intermediate frequency signal enables the selected channel to be selected from other channels. Noise levels and false signals A minimum. 0828-A40107TWF; VINCENT.ptd 1244864 22 The receiver as described in the item μ of the patent application range, and the second oscillator both include: "the younger brother-the divisor Nth; the frequency divider 'divides the reference frequency FR of the reference signal by the phase frequency detection An output terminal of a frequency divider of the detector; a charge pump having an output terminal; having a first input terminal coupled to the first input terminal coupled to the phase frequency detector and a filter; An input terminal is coupled to the output terminal of the charge pump wheel voltage-controlled oscillator; and an input terminal is coupled to the loop tear-off first frequency divider, and an input terminal is connected to the voltage-controlled oscillator. Signal frequency: Divide by a divisor P to round out the first or second vibrating signal. Based on the letter, a frequency multiplier, multiply the first or second oscillating signal by one M, and have an output The terminal is coupled to the second terminal of the phase frequency detector. Brother 2 3 · The receiver as described in item 22 of the patent application scope, wherein ν, ρ and M are determined by the selected channel 24. The receiver according to item 20 of the scope of patent application, wherein A low-noise amplifier is coupled between the antenna and the first mixer to amplify the radio frequency signal. Using a receiver as described in item 20 of the patent application scope, which includes a The surface acoustic wave driver is lightly connected to an output end of the third mixer. 0828-A40107TWF; VINCENT, ptd Page 17 1244864__ VI. Patent Application Range 2 6. The receiver described in Item 20 of the Patent Application Range, wherein the first, second and third mixers are image rejection Mixer. 0828-A40107IW; VINCENT.ptd Page 18