KR19990056534A - Frequency converter with frequency divider - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency converter using a frequency divider, and more particularly, to a frequency configuration of a frequency rising converter that is used to convert a modulated intermediate frequency signal into a high frequency band in a personal mobile communication system.

In the present invention, in converting an input signal of 4.95 MHz into an output signal of 1840-1870 MHz, the first intermediate frequency is selected as 41.2 MHz, and the second intermediate frequency is set as 186.2 MHz, and the oscillation frequency of the first local oscillator is set for this purpose. At 145 MHz, select the oscillation frequency of the second local oscillator from 1653.8 to 1683.8 MHz.

The present invention therefore comprises: a first mixer for mixing a output of a frequency divider with an input signal to produce a first intermediate frequency signal; A second mixer for mixing the first intermediate frequency signal with the first local oscillation frequency signal to produce a second intermediate frequency signal; A third mixer for mixing the second intermediate frequency signal and the second local oscillation frequency signal to produce an output signal; A first local oscillator for generating a fixed first local oscillation frequency signal; A second local oscillator for generating a second local oscillation frequency signal; And a frequency divider that receives and distributes the output signal of the first local oscillator and provides the divided signal to the first mixer.

According to the present invention, by appropriately selecting an intermediate frequency in a frequency rising converter in which a plurality of local oscillators are required, an effect of simplifying the configuration of the circuit and reducing the production cost by using a frequency divider which divides and uses the frequency of the fixed local oscillator is obtained. Can be.

Description

Frequency converter with frequency divider

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a frequency converter using a frequency divider. In particular, in a personal communication system (PCS), a high frequency signal is received in response to a modulated intermediate frequency (IF) signal. (Radio Frequency: RF) relates to the frequency configuration of the frequency rising converter used to convert to the band.

At low frequency, the most basic method used to convert the signal spectrum having a baseband to a higher frequency is to use heterodyne. The basic principle of the heterodyne method is that modulation is performed using a specific intermediate frequency (IF) rather than a low frequency (RF) or a voice signal used in actual wireless communication. Therefore, the heterodyne method has an advantage that the amplification and filtering operations can be performed at a fixed center frequency regardless of the received frequency.

In order to perform such a modulation scheme, a mixer is essential, and a mixer is used to synthesize an input frequency with a fixed mixing frequency to generate an intermediate frequency component.

In the transmitter apparatus for transmitting a signal, a mixer is used in an up-converter. The frequency rising converter converts an input frequency signal in the intermediate frequency band into a signal in the desired frequency band. The frequency converter basically includes a frequency mixer, a frequency filter, and a local oscillator (LO) to convert frequencies.

1 is a structural diagram showing a basic configuration of a frequency rising converter according to the prior art. As shown, it consists of three mixers and three local oscillators. Input intermediate frequency signal f ₁ The desired high frequency signal by three mixers f ₄ Is converted to. The signal to be mixed with the input frequency in the mixer is generated in the local oscillator. The local oscillator receives a reference frequency, producing a stable frequency component to be mixed in the mixer. The local oscillator also receives data from the outside and determines the frequency components to generate.

The frequency rising converter configured as described above has an input frequency. f ₁ And output frequency f ₄ The number of frequency mixers and local oscillators is determined according to the spacing and the use of fixed frequencies.

4.95MHz band f ₁ Suppose you take a signal and convert it into a frequency signal in the 1840-1870 MHz band. In this case, depending on the selectivity of the frequency filter, three frequency mixers and a local oscillator are generally required. The use of so many local oscillators complicates circuit configuration and increases production costs. Therefore, in order to simplify the circuit configuration, it is necessary to reduce the number of local oscillators required by selecting an appropriate intermediate frequency.

Accordingly, the present invention solves the above problems, by appropriately selecting the intermediate frequency in the personal mobile communication system, thereby increasing the simplicity and economy of the circuit by reducing the number of local oscillators required, thereby increasing the frequency and frequency for the personal mobile communication base station. It is an object to provide a converter.

1 is a block diagram showing a basic configuration of a frequency rising converter according to the prior art.

2 is a block diagram showing a basic configuration of a frequency rising converter according to the present invention.

One preferred embodiment of the present invention devised to achieve the object as described above,

In converting an input signal of 4.95 MHz into an output signal of 1840-1870 MHz, the first intermediate frequency is selected as 41.2 MHz and the second intermediate frequency is selected as 186.2 MHz, and the oscillation frequency of the first local oscillator is set to 145 MHz. Select the oscillation frequency of the second local oscillator from 1653.8 to 1683.8 MHz.

In the present invention, the frequency converter comprises: a first mixer for mixing the output of the frequency divider with an input signal to produce a first intermediate frequency signal;

A second mixer for mixing the first intermediate frequency signal with the first local oscillation frequency signal to produce a second intermediate frequency signal;

A third mixer for mixing the second intermediate frequency signal and the second local oscillation frequency signal to produce an output signal;

A first local oscillator for generating a fixed first local oscillation frequency signal;

A second local oscillator for generating a second local oscillation frequency signal;

It is preferable to include a frequency divider for receiving and distributing the output signal of the first local oscillator to provide to the first mixer,

The input frequency signal f ₁ , The second intermediate frequency f ₃ When the distribution value of the frequency divider is N, the first local oscillation frequency signal is Is preferably represented by

Preferably, the first and second local oscillators determine a frequency of a signal to be generated based on a reference frequency and data input from an external controller.

The present invention simplifies the circuit by enabling the replacement of local oscillators with frequency dividers by using an appropriate intermediate frequency.

2 is a structural diagram showing a basic configuration of a frequency rising converter according to the present invention. As shown, it consists of three mixers, two local oscillators and one frequency divider.

f ₁ Is a 4.95 MHz intermediate frequency input signal f ₄ Let is a high frequency output signal from 1840 to 1870 MHz. f ₃ If we designate 186.2 MHz, the frequency-raising converter may consist of three frequency mixers, two local oscillators, and one frequency divider.

The first local oscillator LO # 1 is a frequency synthesizer which generates a fixed frequency signal. f ₆ 145 MHz. The second local oscillator (LO # 2) f ₇ That is, it is a frequency synthesizer that generates frequencies in the 1653.8 ~ 1683.8MHz band. To generate an output signal in the 1840-1870 MHz band when a 4.95 MHz input signal comes in f ₃ Is set to 186.2 MHz. then f ₆ Is determined as in Equation 1.

If N is 4 f ₆ Is 145 MHz, f ₅ Becomes 36.25 MHz.

The frequency rising converter configured as described above receives data necessary for the frequency synthesizer by an external controller. The first local oscillator LO # 1 is controlled by an external controller. f ₆ That is, it generates a signal of 145MHz, the second local oscillator (LO # 2) is likewise by an external controller f ₄ - f ₃ = f ₄ Generates a signal of -186.2 MHz. As a result, mixer # 3 f ₄ = 1840 ~ 1870MHz will generate the desired output signal.

The present invention operating as described above has the effect of simplifying the configuration of the circuit and reducing the production cost by replacing the local oscillator with a frequency divider by appropriately setting the intermediate frequency in a frequency rising converter in which a plurality of local oscillators are needed. Can be.

Claims (4)

In converting an input signal of 4.95 MHz into an output signal of 1840-1870 MHz, the first intermediate frequency is selected as 41.2 MHz and the second intermediate frequency is selected as 186.2 MHz, and the oscillation frequency of the first local oscillator is set to 145 MHz. A frequency converter using a frequency divider, selecting an oscillation frequency of the second local oscillator from 1653.8 to 1683.8 MHz. The method of claim 1, wherein the frequency converter, A first mixer for mixing the output of the frequency divider with the input signal to produce a first intermediate frequency signal; A second mixer for mixing the first intermediate frequency signal with the first local oscillation frequency signal to produce a second intermediate frequency signal; A third mixer for mixing the second intermediate frequency signal and the second local oscillation frequency signal to produce an output signal; A first local oscillator for generating a fixed first local oscillation frequency signal; A second local oscillator for generating a second local oscillation frequency signal; And And a frequency divider for receiving and distributing the output signal of the first local oscillator and providing it to the first mixer. The method of claim 2, wherein the input frequency signal f ₁ , The second intermediate frequency f ₃ When the distribution value of the frequency divider is N, the first local oscillation frequency signal is Frequency converter using a frequency divider, represented by. 3. The frequency converter of claim 2, wherein the first and second local oscillators determine a frequency of a signal to be generated, based on a reference frequency and data input from an external controller.