KR20050019221A - Gps rf receiver - Google Patents

Abstract

PURPOSE: A GPS RF receiver is provided to economically and spatially obtain gains by replacing an interstage SAW filter, installed to cancel an image frequency component between the output block of an LNA(Low Noise Amplifier) and the input block of a mixer, with an LC notch filter. CONSTITUTION: A GPS RF receiver comprises an RF front-end SAW filter(210), an LNA(220), a notch filter(230), a VCO(240), a mixer(250), and an IF SAW filter(260). The RF front-end SAW filter(210) removes noises from an RF signal received through a GPS antenna and outputs it to the LNA(220). The LNA(220) executes low noise amplification for the RF signal outputted from the RF front-end SAW filter(210) and outputs it to the notch filter(230). The notch filter(230) cancels noises from the amplified RF signal. The VCO(240) generates a local frequency signal based on a voltage control signal outputted from a PLL and outputs it to the mixer(250). The mixer(250) mixes the RF signal outputted from the notch filter(230) with the local frequency signal outputted from the VCO(240) and outputs an IF signal to the IF SAW filter(260). The IF SAW filter(260) removes noises from the IF signal outputted from the mixer(250).

Description

GPS RF receiver {GPS RF RECEIVER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a WPS RF receiving device, and in particular, an economical and loading space by designing and inserting an LC notch filter instead of an interstage SAW filter in a WPS front end. The present invention relates to a WPS RF receiver capable of gaining.

1A is a block diagram showing a conventional WPS RF receiving apparatus, which includes a RF front-end SAW filter 110 for removing noise of an RF frequency signal received through a GPS antenna; A low noise amplifier (LNA) 120 for low noise amplifying a signal of each RF frequency output from the RF front-end SAW filter 110; An interstage SAW filter 130 for removing noise of each RF frequency signal amplified by a low noise amplifier (LNA) 120; A VCO 140 generating a local frequency signal of a band according to the voltage control signal output from the PLL (not shown); A mixer 150 for mixing the RF frequency signal output from the interstage SAW filter 130 and the local frequency signal output from the VCO 140 to output a receiving side IF frequency of a predetermined band; And an IF SAW filter 160 for removing noise of the IF frequency signal output from the mixer 150.

As described above, the conventional WPS RF receiving device is equipped with an interstage SAW filter 130 between the output of the low noise amplifier (LNA) 120 and the input of the mixer 150, which is the Image filter for removing images.

FIG. 1B is an exemplary diagram illustrating image frequency components represented by a general mixer, and illustrates the appearance of image frequency components by an example in which an IF frequency of 100 MHz and a local frequency of 700 MHz are converted to 800 MHz by an up mixer. It is for. As shown in FIG. 1B, the same waveform as the 800 MHz band is generated not only in the 800 MHz band but also in the 600 MHz band, which is called an image frequency. Since the image frequency is an unwanted component, it is removed through a filter. That is, LO + IF = RF is a component necessary for reception, and LO-IF = RF is a component not necessary for reception, so that the filter is filtered. The reason why the degradation of the system at this image frequency is more prominent at the receiving end than at the transmitting end is that when 2LO-RF is input in the down mixer, LO- (2LO-RF) = RF-LO = IF, It will act as a noise to the IF actually produced by the. For this reason, the 2LO-RF (= 2LO- (LO + IF) = LO-IF) band should always be clean and it is the interstage SAW filter 130 that plays this role.

However, the above-described conventional GPS RF receiving apparatus is directed toward the development trend in which the current portable terminal is aimed at a multimedia terminal in which various functions are combined, and despite the decrease in cost and mounting area, the interstage Since the SAW filter 130 needs to be mounted, there is a problem in that the cost is high and the mounting area is occupied in the PCB.

In order to solve the above problems, the present invention provides an interstage SAW filter 130 mounted between an output terminal of a low noise amplifier (LNA) 120 and an input terminal of a mixer 150 as an LC notch filter. It is an object of the present invention to provide a WPS RF receiving apparatus which can obtain a cost and a mounting area.

In order to achieve the above object, the GPS RF receiver of the present invention comprises: an RF front-end SAW filter for removing noise of an RF frequency signal received through a GPS antenna; An LNA for low noise amplifying a signal of each RF frequency output from the RF front-end SAW filter; A notch filter for removing noise of each RF frequency signal amplified by the LNA by an LC resonance structure; A VCO generating a local frequency signal; A mixer for mixing the RF frequency signal output from the notch filter and the local frequency signal; And an IF SAW filter for removing noise of the signal output from the mixer.

Hereinafter, the most preferred embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily implement the technical idea of the present invention. .

First, FIG. 2 is a block diagram illustrating a WPS RF receiving device according to an embodiment of the present invention. The WPS RF receiving device of the present invention includes an RF front-end SAW filter 210 and a low noise amplifier (LNA). 220, notch filter 230, VCO 240, mixer 250, and IF SAW filter 260.

The RF front-end SAW filter 210 removes noise of the RF frequency signal received through the GPS antenna and then outputs the noise to a low noise amplifier (LNA) 220 to be described later.

In addition, the low noise amplifier (LNA) 220 low noise amplifies a signal of each RF frequency output from the RF front-end SAW filter 210 and then outputs the notch filter 230 to be described later. .

Meanwhile, the notch filter 230 removes noise of each RF frequency signal amplified by the low noise amplifier (LNA) 220 by a resonance structure, thereby removing an image frequency signal appearing in the mixer 250 to be described later. Play a role.

In addition, the VCO 240 generates a local frequency signal of a band according to a voltage control signal output from a PLL (not shown), and outputs the local frequency signal to a mixer 250 to be described later.

Meanwhile, the mixer 250 mixes the RF frequency signal output from the notch filter 230 and the local frequency signal output from the VCO 240 to describe an IF IF signal of a predetermined band, which will be described later. It prints in).

In addition, the IF SAW filter 260 serves to remove noise of the IF frequency signal output from the mixer 250.

FIG. 3 is a circuit diagram illustrating a notch filter 230 installed in a GPS RF receiver according to an embodiment of the present invention.

Inductor (L), the first terminal forms the input terminal of the notch filter 230, the second terminal forms the output terminal of the notch filter 230, and serves to provide inductance.

In addition, the capacitor C is connected to the inductor L in parallel to serve to provide capacitance. Here, the inductance of the inductor L and the capacitance of the capacitor C are respectively 3.9 to 4.1 nH (most preferably 4.0 nH) and 5.0 to 5.4 pF (According to ADS (Advanced Designed System)). Most preferably, a resonant structure of 5.2 pF) is most preferred. In addition, a plurality of parallel LC circuits as shown in FIG. 3 may be connected in series in the notch filter 230 to provide impedance.

4A and 4B are graphs illustrating a simulation result according to a WPS RF receiving apparatus according to an embodiment of the present invention. Referring to this, the operation of the WPS RF receiving apparatus according to an embodiment of the present invention will be described as follows. .

According to FIG. 4A, the notch filter 230 having the resonance structure of FIG. 3 has an attenuation of 25 dB or more in the about 1.1 GHz band and almost no attenuation in the about 1.6 GHz band (about 0.5 dB). Here, the GPS local frequency applied to the present invention is 1355.04MHz, IF is 220.38MHz, LO-IF is 1134.66MHz. In addition, the GPS band is about 2MHz, so if a large attenuation of about 1134.66MHz ± 10MHz can remove the image frequency.

According to FIG. 4b, it is generally matched to -9 dB in the 1.6 GHz GPS band. In other words, the notch filter is much more advantageous than the -2dB of the SAW filter, and the mounting area is also greatly reduced because it uses L and C elements.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited to the drawings shown.

The present invention has an advantage of gaining cost and mounting area by replacing an interstage SAW filter, which is mounted between an output stage of a low noise amplifier (LNA) and an input stage of a mixer, with an LC notch filter. .

1A is a block diagram showing a conventional WPS RF receiving apparatus;

1B is an exemplary diagram showing an image frequency component represented by a general mixer;

2 is a block diagram showing a GPS RF receiving apparatus according to an embodiment of the present invention;

3 is a circuit diagram showing a notch filter mounted in a GPS RF receiver according to an embodiment of the present invention;

4A and 4B are graphs showing simulation results according to a GPS RF receiving apparatus according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

210: RF front-end SAW filter 220: LNA

230: notch filter 240: VCO

250: Mixer 260: IF SAW Filter

Claims (5)

An RF front-end SAW filter for removing noise of the RF frequency signal received via the GPS antenna; An LNA for low noise amplifying a signal of each RF frequency output from the RF front-end SAW filter; A notch filter for removing noise of each RF frequency signal amplified by the LNA by an LC resonance structure; A VCO generating a local frequency signal; A mixer for mixing the RF frequency signal output from the notch filter and the local frequency signal; And IF SAW filter to remove noise of the signal output from the mixer GPRS RF receiving apparatus comprising a. The method of claim 1, wherein the notch filter, LC circuits connected in parallel to each other GPRS RF receiving apparatus comprising a. The method of claim 2, wherein the notch filter is Connecting the plurality of LC circuits in series A GPS RF receiver, characterized in that. The method of claim 1, Inductance value of the inductor included in the LC circuit is 3.9 ~ 4.1nH A GPS RF receiver, characterized in that. The method according to claim 1 or 4, Capacitance value of the capacitor included in the LC circuit is 5.0 ~ 5.4pF A GPS RF receiver, characterized in that.