KR20020074572A - Radio frequency mode data Transponder - Google Patents

Abstract

PURPOSE: An RF(Radio Frequency) transceiver system for data transmission is provided to cut expense, to ensure a stable operation, to secure the reliability of products, and to improve productivity by generating a local oscillation frequency through an oscillator synchronized with a received frequency and using only one stable IF(Intermediate Frequency) crystal oscillator in a transceiver. CONSTITUTION: An RF transceiver system for data transmission consists of a received signal amplification part(20), a synchronous signal generation part(30), an RF receiving part(50), and an RF transmitting part(60). The received signal amplification part(20) amplifies the signal received to an antenna(10). The synchronous signal generation part(30), synchronized with the received frequency, generates a synchronous signal. The RF receiving part(50) is composed of a local oscillation frequency generator(50A) and a received signal regeneration part(50B). The local oscillation frequency generator(50A) mixes an output signal based on the synchronous signal with an IF crystal oscillator(40) and generates a local oscillation frequency. The received signal regeneration part(50B) regenerates the received signal using the local oscillation frequency. The RF transmitting part(60) is composed of a Tx data converter(60A), a Tx carrier generation part(60B), and an amplification part(60C). The Tx data converter(60A) adds a signal, inputted from a terminal, to the IF crystal oscillator(40) and converts Tx data. The Tx carrier generation part(60B) mixes the data obtained from the Tx data converter(60A) with the signal outputted from the synchronous signal generation part(30) and generates a Tx frequency. The amplification part(60C) amplifies the Tx frequency.

Description

RF transmission / reception device for data transmission {Radio frequency mode data Transponder}

The present invention relates to a radio frequency (RF) transceiver for data transmission.

In general, RF data transmission / reception devices for transmitting RF data to terminals such as PDAs, mobile phones, or PCs through repeaters and public communication networks, or transmitting data from these terminals to repeaters through public communication networks, have a high range of 400 MHz to 2.5 GHz. It is configured to process the frequency, and it is essential to use the superheterodyne method, which is easy to configure the circuit, in order to secure the proper sensitivity of the receiver. At this time, a local oscillation frequency for approaching the corresponding frequency is required.

The oscillator used in the existing products generally uses a relatively stable crystal oscillator, but the crystal is difficult to secure the characteristics of 50MHz or more due to its physical characteristics, and it is difficult to use it for a large quantity of products due to the price issue. There is a difficulty.

Therefore, in the existing products using high frequency, a phase tracking circuit called PLL is used. In order to obtain a stable frequency, a low frequency crystal oscillator (less than 50MHz) should be used as the reference frequency. The stability of oscillator is maintained, but considering that the stability of crystal is 3PPM in general product, when the frequency used is 1GHz, the frequency deviation of oscillator is over 3KHz, which means that the voice communication band is 300Hz to 3400Hz. Given this, there is a problem that it is difficult to secure stable communication.

In addition, in the case of the transmission / reception scheme, a separate oscillation circuit is required for each transmission / reception, which acts as a cost increase factor of the product.

As described above, the frequency varies greatly according to the characteristics of components, the ambient temperature, and the power supply voltage, so that a more stable oscillation frequency is not obtained. Therefore, the reliability of the device is greatly deteriorated, the production cost is high, and high quality communication is difficult to secure. .

An object of the present invention is to improve the circuit stability of the RF transceiver device to stabilize the operation of the device and to reduce the manufacturing cost thereof.

In general, in the RF transceiver, a repeater, which is an expensive product, is manufactured to operate in a relatively stable transmission frequency, and one repeater is configured to control a plurality of terminals. Of course, the product must be made at a low price.

However, high frequency stable oscillation circuit is essential for the stable operation of the terminal, and a large part of the manufacturing cost is put to improve the stability of the frequency. When the operation is stopped (e.g., wireless devices installed and operated outdoors such as a wireless street light controller), it is very difficult to make a stable oscillator close to the reception frequency in a mobile device even if a large amount of material is input. to be.

The present invention generates a local oscillation frequency with an oscillator synchronized with the reception frequency and uses only one stable crystal oscillator of low frequency (intermediate frequency) inside the transceiver, thereby reducing costs and ensuring stable operation and ensuring product reliability. Improving productivity is a technical challenge.

According to an aspect of the present invention, there is provided a reception signal amplifier for amplifying a signal received by an antenna, a synchronization signal oscillator for generating a synchronization signal in synchronization with a reception frequency, an output signal and an intermediate frequency crystal oscillator with a synchronization signal. The RF receiver comprises a local oscillation frequency generator for generating a local oscillation frequency by mixing a signal and a reception signal regeneration unit for reproducing the received signal by the local oscillation frequency, and adds the signal input from the terminal to the intermediate frequency crystal oscillator to transmit the data. The transmission data converter for converting, and the RF transmission unit consisting of a transmission carrier generator for generating a transmission frequency by mixing the data obtained from the transmission data converter and the signal output from the received signal synchronization oscillator and amplifying it .

1 is a circuit block diagram of the present invention

2 is a detailed circuit diagram according to an embodiment of the present invention.

Description of the main parts of the drawing

10: antenna 20: receiving signal amplifier

21: low noise amplifier 22: RF amplifier

23: buffer amplifier 30: synchronization signal oscillator

31: Onion Rectifier 32: Dispensing Circuit

33: synchronous oscillator 40: medium frequency crystal oscillator

50: RF receiver 50A: local oscillation frequency generator

50B: receiving signal reproducing unit 60: RF transmitting unit

60A: transmission data converter 60B: transmission carrier generator

60C: Amplifier

The present invention is to use the built-in configuration of the present invention in a terminal such as a PDA or a mobile phone or a PC or as a separate module to connect to the terminal and transmit data to the repeater.

1 is a circuit block diagram of the present invention, which includes a reception signal amplifier 20 for amplifying a signal received by an antenna 10, a synchronization signal oscillator 30 for generating a synchronization signal in synchronization with a reception frequency, and synchronization. A local oscillation frequency generator 50A for mixing the output signal by the signal with the intermediate frequency crystal oscillator 40 to generate a local oscillation frequency, and a reception signal regeneration unit 50B for reproducing the received signal by the local oscillation frequency. A transmission data converter 60A which adds an RF receiver 50, a signal input from the terminal to the intermediate frequency crystal oscillator 40 to convert transmission data, and data obtained from the transmission data converter 60A and a synchronization signal oscillator ( 30 is composed of a transmission carrier generation unit 60B for generating a transmission frequency by mixing the signal output from 30 and an RF transmission unit 60 composed of an amplification unit 60C for amplifying it.

The reception channel filter 70 and the transmission channel filter 80 are installed between the reception signal amplifier 20, the RF transmitter 60, and the antenna 10. 90 in the figure is a power supply voltage controller.

2 is a circuit configuration diagram according to an embodiment of the present invention is connected to a repeater and a wireless network not shown to perform RF transmission and reception, in which case the repeater should always transmit the transmission carrier frequency.

That is, the reception signal amplifier 20 amplifies the channel selection signal filtered by the 938-940 MHz reception channel filter 70 received by the antenna 10, and generates a synchronization signal in synchronization with the reception frequency (940 MHz). The intermediate frequency corresponding to the difference by mixing the synchronous signal oscillator 30 and the output frequency of the synchronous signal by mixing the intermediate frequency (40 MHz) and the output of the difference-synchronized oscillator (900 MHz) with the receiving frequency (940 MHz). The RF receiver 50 restores the data received by the phase shift extractor at 40 MHz and inputs it to the terminal, and phase modulates the transmission data to an intermediate frequency, and then synchronizes the received frequency (940 MHz) of the synchronization signal oscillator 30. It is a RF transmitter 60 for data transmission that obtains a transmission frequency by mixing with the output of the oscillator and amplifies it to a desired force and transmits and receives with a repeater and a terminal using a single crystal oscillator 40. It is to break.

The reception signal amplifier 20 amplifies the signal filtered from the 938 to 940 MHz reception channel filter 70 by the first and second amplification by the low noise amplifier 21 and the RF amplifier 22 to receive the RF receiver 50. ) Is input to the mixer 51 side, and amplified by the buffer amplifier 23 and input to the onion rectifier 31 of the synchronization signal oscillator 30. 24 in the received signal amplifier 20 is a 938-940 MHz band filter, and 25 is an AGC circuit.

The synchronizing signal oscillator 30 removes a phase modulated signal by the onion rectifier 31 and the divider circuit 32 (or D flip-flop) from the signal amplified by the buffer amplifier 23 (in case of AM modulation). And a pure carrier component as a signal of the 940 MHz synchronous oscillator 33, and inputs the output signal of the synchronous oscillator 33 to the buffer amplifier 52 side of the RF receiver 50 side. At the same time, the output signal of the intermediate frequency crystal oscillator 40 is input to the mixer 60B-2 of the transmission carrier generator 60B. 34 is a reception band filter of 938MHz to 940MHz for parallel resonance. In the above, when the AM modulation is used in the RF transmitter / receiver 50 or 60 without using the two-phase modulator / demodulator described later, the configuration of the frequency divider 32 can be omitted.

The RF receiver 50 amplifies the oscillation frequency of the 40 MHz (intermediate frequency) crystal oscillator 40 by the buffer amplifier 54 to the other input terminal of the mixer 53 connected to the output terminal of the buffer amplifier 52. The input frequency is selected as the input signal of the 900 MHz synchronous oscillator 56 by selecting the frequency of the difference of the mixed frequencies by the received frequency-intermediate frequency band filter (55: 898 MHz to 900 MHz) among the mixed frequencies, and outputting the output to the mixer 51. Input the received signal amplification unit 20 output to the other input terminal of the mixer 51, the intermediate frequency (40MHz) selector 57 is connected to the mixer 51 output terminal to select the intermediate frequency, the intermediate frequency In the amplifier 50-1, the waveform received by the phase shift extractor 58 (two-phase demodulator) is waveform-formed by the waveform shaper 59 and input to the terminal. 50-1 in the figure is an intermediate frequency amplifier.

In addition, the transmission data converter 60A of the RF transmitter 60 includes a waveform shaping circuit 60A-1 for waveform shaping data input from a terminal, a crystal oscillator 40 for generating an intermediate frequency (40 MHz) signal, and And a 2PSK modulator 60A-5 for two-phase modulation of the signal amplified by the buffer amplifier 60A-2, a buffer amplifier 60A-3, and an intermediate frequency (40 MHz) selector 60A-4.

In addition, the transmission carrier generator 60B of the RF transmitter 60 inputs an oscillation frequency synchronized with the reception frequency to the buffer amplifier 60B-1 of the transmitter carrier generator 60B and amplifies the 40 MHz phase modulation. And a mixer 60B-2 for mixing the signal (the output signal of the 2PSK modulator) and the transmission band filter 60B-3 of 898 to 900 MHz.

That is, the RF transmitter 60 converts the waveform-formed signal through the waveform shaping circuit 60A-1 for shaping the data inputted from the terminal and the oscillation frequency of the 40MHz crystal oscillator 40 into the buffer amplifier 60A-2. Inputs to the 2 PSK modulator 60A-5 which modulates the signal amplified by the 2-phase, and connects the intermediate frequency (40 MHz) selector 60A-4 to the 2PSK modulator 60A-5 impact. The oscillation frequency synchronized with the reception frequency is inputted to the buffer amplifier 60B-1 of the transmission carrier generator 60B, and the 40 MHz phase modulation is provided to the input side of the transmission carrier generator 60B. And a mixer 60B-2 for mixing the signal (the output signal of the 2PSK modulator) and the transmission band filter 60B-3 of 898 to 900 MHz.

In addition, the amplifier 60C of the RF transmitter 60 is an RF amplifier, and all of the buffer amplifier circuits in the drawing may be omitted when designed using a high input impedance element such as an FET.

As described above, the present invention uses the oscillator 33 synchronized to a high reception frequency to prevent the oscillation frequency from changing in response to changes in ambient temperature, voltage, and ambient environment. After obtaining the frequency (typically 50 MHz or less) and mixing it with the receiving frequency (400 MHz to 2.5 GHz), the frequency of the difference between the two frequencies (receive frequency ± intermediate frequency) is used as the local oscillation frequency. Since the error range at the oscillating frequency is not exceeded, the stability is improved by the magnification of the local oscillation frequency and the intermediate frequency as compared with the PLL method.

If the actual receiving frequency is 1GHz, the conventional PLL method and the frequency error range are calculated.The PLL method has a local oscillation frequency (960MHz) * crystal stability (3PPM) = 2880Hz, and this method has an intermediate frequency (40MHz) * crystal stability ( Since 3PPM) = 120Hz, more than 24 times stability can be obtained, and the performance improvement of the device is very large.

In addition, since the transmission frequency is obtained by mixing the oscillation frequency synchronized with the reception frequency with the intermediate frequency, the transmission frequency also operates very stably, and the remote control function of the transmission frequency by using the characteristic that the transmission frequency changes in proportion to the reception frequency You can also implement

In this way, the oscillator 33 synchronized to the reception frequency generates a local oscillation frequency, and by using only one low frequency (middle frequency) stable crystal oscillator 40 inside the transceiver, it is possible to reduce costs and ensure stable operation. Improved productivity by ensuring the reliability of.

The present invention improves the reliability of the device by improving the circuit stability of the RF transceiver, regardless of the ambient temperature change, power supply, and ambient environment inside the device by constructing a built-in oscillator synchronized with the received frequency. Since the transmission channel frequency changes proportionally according to the channel frequency, the channel selection is easy and the RF transceiver can be configured as a single crystal oscillator by using the frequency of the difference between the transmission and reception frequencies as an intermediate frequency. It has the effect of reducing the cost of manufacturing and manufacturing.

Claims (4)

A reception signal amplifier 20 for amplifying a signal received by the antenna 10, a synchronization signal oscillator 30 for generating a synchronization signal in synchronization with the reception frequency, an output signal and an intermediate frequency crystal oscillator (i.e. A RF receiver 50 composed of a local oscillation frequency generator 50A for mixing a local oscillation frequency to generate a local oscillation frequency, and a reception signal regeneration unit 50B for reproducing a received signal by the local oscillation frequency; A transmission data converter 60A which adds a signal to the intermediate frequency crystal oscillator 40 to convert transmission data; a signal obtained by mixing the signal obtained from the transmission data converter 60A with the signal output from the synchronization signal oscillator 30; RF transmission and reception with the repeater and the terminal is made up of the RF transmitter 60 consisting of a transmission carrier generator 60B for generating a signal and an amplifier 60C for amplifying it. RF transmitting and receiving device for transmitting data, characterized in that. The synchronization signal oscillator 30 removes a phase modulated signal by the onion rectifier 31 and the frequency divider circuit 32 from the signal amplified by the buffer amplifier 23 so as to synchronize only a pure carrier component with a 940 MHz synchronization. Mixer 53 used as a signal of the oscillator 33 and mixing the output signal of the synchronous oscillator 33 with the output signal of the intermediate frequency crystal oscillator 40 through the buffer amplifier 52 on the RF receiver 50 side. And an input to the mixer (60B-2) of the transmission carrier generator (60B). The RF receiver 50 amplifies the oscillation frequency of the 40 MHz crystal oscillator 40 by the buffer amplifier 54 at the other input terminal of the mixer 53 connected to the output terminal of the buffer amplifier 52. The input frequency is selected as the input signal of the 900 MHz synchronous oscillator 56 by selecting the frequency of the difference of the mixed frequencies by the received frequency-intermediate frequency band filter (55: 898 MHz to 900 MHz) among the mixed frequencies, and outputting the output to the mixer 51. Input the received signal amplification unit 20 output to the other input terminal of the mixer 51, the intermediate frequency (40MHz) selector 57 is connected to the mixer 51 output terminal to select the intermediate frequency, the intermediate frequency RF for data transmission, characterized in that the waveform received by the phase shift extractor 58 (two-phase demodulator) through the amplifying unit 50-1 is waveform-formed by the waveform shaper 59 and transmitted to the terminal. Transceiver. The RF transmitter of claim 1, wherein the RF transmitter 60 buffers the waveform-formed signal through the waveform shaping circuit 60A-1 for shaping the data input from the terminal and the oscillation frequency of the 40MHz crystal oscillator 40. Input the 2PSK modulator (60A-5) which modulates the signal amplified by (60A-2) to 2-phase, and connect the intermediate frequency (40MHz) selector (60A-4) to the output of the 2PSK modulator (60A-5). A 40 MHz signal and an amplified signal which are supplied to the input side of the transmission carrier generator 60B of the transmitter 60, and then inputted to the buffer amplifier 60B-1 of the transmitter carrier generator 60B, which is in synchronization with the reception frequency. And a mixer (60B-2) for mixing a phase modulation signal (output signal of a 2PSK modulator) and a transmission band filter (60B-3) of 898 to 900 MHz.