Patent Description:
Measurement of signal characteristics of a millimeter wave band used for <NUM>, such as channel power and error vector magnitude (EVM), is performed by connecting a wideband signal analyzer for signals of several tens of GHz to a millimeter wave band frequency down converter. The millimeter wave band frequency down converter has a structure in which a local signal source required for frequency up/down conversion is supplied through a local signal output of a signal generator or a separate signal generator. In addition, a distance between the local signal sources and the millimeter wave band frequency down converter should be reduced in order to conduct the Over-the-Air (OTA) test using chambers, jigs, and antennas. In general, a local oscillator (LO) signal required for the millimeter wave band frequency up/down converter is supplied through a LO output of the signal analyzer or the LO signal generator. However, in a case where the distance between these devices and the millimeter wave band frequency converter should be far apart from each other, there is a difficulty due to loss according to a length of a LO signal path when it is necessary to secure a sufficient distance and space in a test environment in order to supply sufficient electromagnetic power to a LO port input of the millimeter wave band frequency converter.

In addition, since the LO signal supplied by a typical signal analyzer supplies only a constant power value according to a frequency, the loss of the LO path connected from the LO output port of the signal analyzer to the millimeter wave band frequency down converter is different for each frequency, so there is a disadvantage that it is difficult to supply optimal LO power.

Therefore, when the distance between the signal analyzer and the millimeter wave band frequency up/down converter is greater than or equal to a predetermined distance, a separate expensive signal generator (having <NUM> to <NUM> frequency range, and +<NUM> dBm or more output level) that may supply the optimal LO signal power is required.

Feridoon Jalili et al. describe the new generation of <NUM> mobile communications systems using millimeter active phased arrays which have up to hundreds of individual analog transmitter and receiver chains and antennas in the paper entitled "<NPL>.

An objective of the present disclosure is to provide a <NUM> millimeter wave band OTA measurement system configured to supply a LO signal required for a frequency converter by compensating for a local signal source loss due to a distance between the frequency converter and devices of a signal analyzer and a signal generator in order to conduct an Over-the-Air (OTA) test of a signal frequency.

These problem solutions will become more apparent from the following detailed description of the present disclosure based on the accompanying drawings.

Prior to this, the terms or words used in the present specification and claims should not be construed as conventional and dictionary meanings. On the contrary, based on the principle that the inventor can appropriately define the concept of a term in order to describe his or her invention in the best way, it should be interpreted as meaning and concept consistent with the technical idea of the present disclosure.

That is, according to the exemplary embodiment of the present disclosure, in order to conduct the Over-the-Air (OTA) test of signals generated in a first frequency assembly <NUM> through a Tx antenna and an Rx antenna, the LO signal of the optimized magnitude required for the frequency up converter and the frequency down converter may be stably supplied by compensating for the local signal source loss due to the distance between devices of the signal analyzer and signal generator and the frequency up converter and frequency down converter that deal with <NUM> millimeter wave band.

The specific aspects and specific technical features of the present disclosure will become more apparent from the following detailed description and exemplary embodiments in conjunction with the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used to refer to the same components as much as possible even if displayed on different drawings. In addition, in the following description of the exemplary embodiment of the present disclosure, detailed descriptions of related known functions and components incorporated herein will be omitted when it is determined that the subject matter of the present disclosure may be obscured thereby.

Further, when describing the components of the present disclosure, terms such as first, second, A, B, (a) or (b) may be used. Since these terms are provided merely for the purpose of distinguishing the components from each other, they do not limit the nature, sequence, or order of the components. When a component is described as being "connected", "coupled", or "linked" to another component, that component may be directly connected or connected to that other component. However, it should be understood that yet another component between each of the components may be "connected", "coupled", or "linked" to each other.

Hereinafter, the exemplary embodiment of the present disclosure will be described in detail on the basis of the accompanying drawings.

As shown in <FIG>, the <NUM> millimeter wave band Over-the-Air (OTA) measurement system according to the exemplary embodiment of the present disclosure may be configured to include: a first frequency assembly <NUM> configured to generate an intermediate frequency (IF) signal and a LO signal to transmit a signal frequency to outside; and a second frequency assembly <NUM> configured to receive and analyze the signal frequency transmitted from the first frequency assembly <NUM>.

The first frequency assembly <NUM> may be configured to include: a signal generator <NUM> configured to generate a signal frequency; a level control device <NUM> configured to amplify a Tx LO signal generated by the signal generator and compensate for mismatches; a frequency up converter <NUM> configured to up-convert the signal frequency by synthesizing a frequency signal; and a Tx antenna <NUM> configured to transmit the signal frequency to outside.

The signal generator <NUM> is configured to include: a LO signal generator configured to generate a LO signal; and an IF signal generator configured to generate an IF signal, wherein the Tx LO signal generated by the LO signal generator may be transmitted to the level control device <NUM> and the IF signal generated by the IF signal generator may be transmitted to the frequency up converter <NUM>.

The level control device <NUM> performs functions of receiving the Tx LO signal generated by the LO signal generator and amplifying the Tx LO signal to a maximum output, and compensating for mismatches generated when amplifying the Tx LO signal to the maximum output or receiving the signal frequency transmitted from the signal generator <NUM> to the level control device <NUM>.

Specifically, as shown in <FIG>, the level control device <NUM> may be configured to include: an input terminal <NUM> configured to receive a Tx LO signal generated by the signal generator <NUM>; attenuators <NUM>, <NUM>, <NUM>, and <NUM> configured to amplify the signal or compensate for signal mismatches generated when receiving the signal; amplifiers <NUM> and <NUM> configured to amplify the signal; a negative slope equalizer <NUM> configured to compensate, with a negative level attenuation value, for a signal frequency corrected through the amplifiers <NUM> and <NUM> and the attenuators <NUM>, <NUM>, <NUM>, and <NUM>; and an output terminal <NUM> configured to output the signal.

The attenuators <NUM>, <NUM>, <NUM>, and <NUM> are configured to include a first attenuator <NUM>, a second attenuator <NUM>, a third attenuator <NUM>, and a fourth attenuator <NUM>, and performs functions of receiving the signal and compensating for the previously generated signal mismatch.

The amplifiers <NUM> and <NUM> may be configured to include a first amplifier <NUM> and a second amplifier <NUM>, and may amplify the Tx LO signal with a maximum output of <NUM> dBm and a gain of <NUM> dM or more.

A negative slope equalizer performs functions of receiving the signal frequency Tx LO obtained by amplifying the signal and compensating for the signal mismatches by the amplifiers <NUM> and <NUM> and the attenuators <NUM>, <NUM>, <NUM>, and <NUM>, and compensating for the received signal frequency with a frequency negative level attenuation value in consideration of a maximum output slope of the second amplifier <NUM> and a level slope according to a length of a cable connected to the output terminal <NUM>.

In addition, the negative slope equalizer <NUM> performs functions of adjusting a slope to forcibly be in a reversed direction by applying characteristics of an RF filter, thereby compensating for the slope in a form of gradually decreasing from a low frequency to a high frequency and compensating for a difference in amplification degrees of active devices such as amplifiers depending on the frequencies.

Next, a sequence of amplifying the Tx LO signal and compensating for the mismatches in the level control device <NUM> so as to adjust an optimal level for the operation of the <NUM> millimeter wave band frequency is as follows.

First, the level control device <NUM> may receive a Tx LO signal through the input terminal <NUM>, transmit the received Tx LO signal to the first attenuator <NUM>, and compensate for a signal mismatch generated while transmitting the Tx LO signal from the signal generator <NUM> to the level control device <NUM>.

The Tx LO signal compensated by the first attenuator <NUM> may be transmitted to the first amplifier <NUM> to amplify the Tx LO signal to the maximum output, and the amplified signal may be transmitted to the second attenuator <NUM>.

The second attenuator <NUM> performs a function of compensating for a signal mismatch generated while amplifying the signal by the first amplifier <NUM>, and transmits the Tx LO signal to the second amplifier <NUM> after adjusting a signal level according to signal input conditions of the second amplifier <NUM>.

The second amplifier <NUM> amplifies the signal by outputting the Tx LO signal input from the second attenuator <NUM> to the value (i.e., the maximum output) output from the first amplifier <NUM>, removes a level change generated in a path of the LO signal source (i.e., cable, etc.), and transmits the Tx LO signal, from which the level change is removed, to the third attenuator <NUM>.

The LO signal source (i.e., Tx LO signal) amplified by the second amplifier <NUM> may be adjusted to a very stable signal for which an extreme level change is compensated.

The third attenuator <NUM> performs a function of compensating for a mismatch generated while amplifying the Tx LO signal in the second amplifier <NUM>, and then transmits the Tx LO signal to the negative slope equalizer <NUM>.

The negative slope equalizer performs functions of receiving the Tx LO signal compensated by the third attenuator <NUM> and compensating for a level slope of a frequency with a frequency negative level attenuation value in consideration of the maximum output slope of the second amplifier <NUM> and the length of the cable connected to the output terminal <NUM>. Thereafter, the negative slope equalizer transmits the Tx LO signal to the fourth attenuator <NUM> so as to compensate for a mismatch generated while transmitting the Tx LO signal from the negative slope equalizer <NUM> to the fourth attenuator <NUM>, and adjusts the Tx LO signal optimized for the <NUM> millimeter wave band frequency level to transmit to the outside (i.e., frequency up converter) through the output terminal <NUM>.

The frequency up converter <NUM> receives each of the Tx LO signal adjusted by the level control device <NUM> and the Tx IF signal generated by the IF signal generator, and performs functions of converting a signal frequency to a Tx RF signal frequency by synthesizing the Tx LO signal and the Tx IF signal and increasing the signal frequency. The Tx RF signal converted by the frequency up converter <NUM> is transmitted to an external device (i.e., the second frequency assembly <NUM> in the present disclosure) through the Tx antenna <NUM>.

The second frequency assembly <NUM> may include: an Rx antenna <NUM> configured to receive an Rx RF signal from the outside; a level control device <NUM> configured to receive the Rx LO signal generated by the signal analyzer, amplify the Rx LO signal, and compensate for a mismatch; a frequency down converter <NUM> configured to down-convert a signal frequency by synthesizing a frequency signal; and a signal analyzer <NUM> configured to receive an Rx IF signal converted by the frequency down converter <NUM> and analyze the Rx IF signal.

The signal analyzer <NUM> is a device that receives the signal frequency converted by the frequency down converter <NUM> and analyzes the signal, and may be provided with a built-in LO signal generator that generates an Rx LO signal, and may transmit the Rx LO signal to the level control device <NUM>.

The level control device <NUM> performs functions of receiving the Rx LO signal generated by the LO signal generator to amplify the Rx LO signal to a maximum output, and compensating for a mismatch generated when amplifying the Rx LO signal to the maximum output or a mismatch generated when receiving the signal frequency from the signal generator to the level control device <NUM>.

Specifically, as shown in <FIG>, the level control device <NUM> may be configured to include: an input terminal <NUM> configured to receive a Rx LO signal generated by the signal generator <NUM>; attenuators <NUM>, <NUM>, <NUM>, and <NUM> configured to amplify a signal or compensate for a signal mismatch generated when receiving the signal; amplifiers <NUM> and <NUM> configured to amplify the signal; a negative slope equalizer <NUM> configured to compensate, with a negative level attenuation value, a signal frequency corrected through the amplifiers <NUM> and <NUM> and the attenuators <NUM>, <NUM>, <NUM>, and <NUM>; and an output terminal <NUM> configured to output the signal.

The attenuators <NUM>, <NUM>, <NUM>, and <NUM> are configured to include a first attenuator <NUM>, a second attenuator <NUM>, a third attenuator <NUM>, and a fourth attenuator <NUM>, and perform functions of receiving a signal and compensating for the previously generated signal mismatch.

The amplifiers <NUM> and <NUM> may be configured to include the first amplifier <NUM> and the second amplifier <NUM>, and may amplify the Rx LO signal with a maximum output of <NUM> dBm and a gain of <NUM> dM or more.

The negative slope equalizer performs functions of receiving a signal frequency Rx LO obtained by amplifying a signal and compensating for a signal mismatch by the amplifiers <NUM> and <NUM> and the attenuators <NUM>, <NUM>, <NUM>, and <NUM>, and compensating for a level slope with a frequency negative level attenuation value in consideration of a maximum output slope of the second amplifier <NUM> and the level slope according to a length of a cable connected to the output terminal <NUM>.

Next, a sequence of amplifying the Rx LO signal and compensating for the mismatch in the level control device <NUM> so as to adjust an optimal level for the operation of the <NUM> millimeter wave band frequency is as follows.

First, the level control device <NUM> may receive a Rx LO signal through the input terminal <NUM>, transmit the received Rx LO signal to the first attenuator <NUM>, and compensate for a signal mismatch generated while transmitting the Rx LO signal from the signal generator <NUM> to the level control device <NUM>.

The Rx LO signal compensated by the first attenuator <NUM> may be transmitted to the first amplifier <NUM> to amplify the Rx LO signal to the maximum output, and the amplified signal may be transmitted to the second attenuator <NUM>.

The second attenuator <NUM> performs a function of compensating for a signal mismatch generated while amplifying the signal by the first amplifier <NUM>, and transmits the Rx LO signal to the second amplifier <NUM> after adjusting a signal level according to signal input conditions of the second amplifier <NUM>.

The second amplifier <NUM> amplifies the signal by outputting the Rx LO signal input from the second attenuator <NUM> to the value (i.e., the maximum output) output from the first amplifier <NUM>, removes a level change generated in a path of the LO signal source (i.e., cable, etc.), and transmits the Rx LO signal, from which the level change is removed, to the third attenuator <NUM>.

The LO signal source (i.e., Rx LO signal) amplified by the second amplifier <NUM> may be adjusted to a very stable signal for which an extreme level change is compensated.

The third attenuator <NUM> performs a function of compensating for a mismatch generated while amplifying the Rx LO signal in the second amplifier <NUM>, and then transmits the Rx LO signal to the negative slope equalizer <NUM>.

The negative slope equalizer performs functions of receiving the Rx LO signal compensated by the third attenuator <NUM> and compensating for a level slope of a frequency with a frequency negative level attenuation value in consideration of the maximum output slope of the second amplifier <NUM> and the length of the cable connected to the output terminal <NUM>. Thereafter, the negative slope equalizer transmits the Rx LO signal to the fourth attenuator <NUM> so as to compensate for a mismatch generated while transmitting the Rx LO signal from the negative slope equalizer <NUM> to the fourth attenuator <NUM>, and adjusts the Rx LO signal optimized for the <NUM> millimeter wave band frequency level to transmit to the outside (i.e., frequency down converter) through the output terminal <NUM>.

That is, the level control device <NUM> configured in the first frequency assembly <NUM> and the level control device <NUM> configured in the second frequency assembly <NUM> may be configured identically, and their functions in which amplification and attenuation are performed are the same except for a difference in that the level control device <NUM> configured in the first frequency assembly generates a signal for transmission and the level control device <NUM> configured in the second frequency assembly generates a signal for reception.

The frequency down converter <NUM> performs functions of receiving each of the Rx LO signal adjusted by the level control device <NUM> and the Rx RF signal received from the Rx antenna <NUM>, synthesizing the Rx RF signal and the Rx LO signal (i.e., Rx RF - Rx LO), and then converting the signal frequency to the Rx IF signal by decreasing the signal frequency. The Rx IF signal converted by the frequency down converter <NUM> may be transmitted to the signal analyzer <NUM>, and the Rx IF signal may be analyzed by the signal analyzer <NUM>.

That is, according to an exemplary embodiment of the present disclosure, in order to conduct the Over-the-Air (OTA) test of the signal generated in the first frequency assembly <NUM> through a Tx antenna <NUM> and a Rx antenna <NUM>, the LO signal of the optimized magnitude required for frequency up converter <NUM> and frequency down converter <NUM> may be stably supplied by compensating for the local signal source loss due to the distance between devices of the signal analyzer <NUM> and signal generator <NUM> and the frequency up converter <NUM> and frequency down converter <NUM> that deal with <NUM> millimeter wave band.

Although the present disclosure has been described in detail through the exemplary embodiment, the exemplary embodiment is for describing the present disclosure in detail, and the <NUM> millimeter wave band OTA measurement system according to the present disclosure is not limited thereto. In addition, terms such as "include", "compose", or "have" described above mean that the corresponding component may be embedded unless otherwise stated, so it should be construed as not excluding other components, but may further include other components. All terms, including technical and scientific terms, have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs, unless otherwise defined.

Claim 1:
A <NUM> millimeter wave band Over-the-Air, OTA, measurement system, the system comprising:
a signal generator (<NUM>) configured to generate a Tx local oscillator, LO, signal and a Tx intermediate frequency, IF, signal;
the system is characterised by
a level control device (<NUM>) configured to receive the Tx LO signal generated by the signal generator (<NUM>), amplify the Tx LO signal to a maximum output, and compensate for mismatches generated when the Tx LO signal is amplified;
a frequency up converter (<NUM>) configured to receive each of the Tx IF signal generated by the signal generator (<NUM>) and the Tx LO signal amplified and compensated by the level control device (<NUM>), and convert a signal frequency to a Tx radio frequency, RF, signal frequency by synthesizing the Tx IF signal and the Tx LO signal and increasing the signal frequency; and
a Tx antenna (<NUM>) configured to transmit the Tx RF converted by the frequency up converter (<NUM>) to outside.