JPH06289124A - Phase detection circuit - Google Patents

Abstract

PURPOSE:To put very accurate phase detecting action into practice by minimizing an increase in hardwear, and controlling influence resulting from frequency characteristics and the unbalance of components. CONSTITUTION:A quantized I signal 14 and a quantized Q signal 15 which are output by an I channel mixer 12 and a Q channel mixer 13 are set up as an address, and the phase value of a measured value which is previously picked from a reference phase-shifter or the like and stored is made to output from a phase value ROM 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase detection circuit for correcting a transmission phase between input and output of an active module which constitutes a phased array radar, for example.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a conventional phase detection circuit. In the figure, 1 is a device input and 2 is a high frequency device (hereinafter referred to as RF) having a device input 1 as an input.
3) is a device output output from the RF device 2, and 4 is a first monitor signal connected to the input side of the RF device 2.

Further, 5 is a distributor having the first monitor signal 4 as an input, 6 is an in-phase channel local port signal (hereinafter referred to as I channel LO signal) output from the distributor 5, and 7 is the above distributor. The other output of 5 is 90
Degree phase difference channel local port signal (hereinafter, referred to as Q channel LO signal), 8 is a second monitor signal connected to the output side of the RF device 2.

Further, 9 is a 90-degree hybrid which receives the second monitor signal 8 and 10 is a 90-degree hybrid 9
In-phase channel high frequency signal output by
I channel RF signal) and 11 are 90 ° phase difference channel high frequency signal (hereinafter referred to as Q channel RF signal) which is another output of the 90 ° hybrid 9.

Further, 12 is the above I channel LO signal 6
An in-phase channel mixer (hereinafter referred to as an I channel mixer) that receives the I channel RF signal 10 and the I channel RF signal 10, and a 90-degree phase difference channel 13 that receives the Q channel LO signal 7 and the Q channel RF signal 11 as inputs. Mixer (hereinafter referred to as Q channel mixer), 14
Is a quantized in-phase signal output from the I channel mixer 12 (hereinafter referred to as a quantized I signal), and 15 is the Q
It is a quantized 90-degree phase difference signal (hereinafter referred to as a quantized Q signal) output from the channel mixer 13.

Reference numeral 19 is an arctangent operation read-only memory (hereinafter referred to as arctangent operation ROM) which receives the quantized I signal 14 and the quantized Q signal 15 as input, and 18 is output from the arctangent operation ROM 19. Phase output.
FIG. 6 is a data table showing the stored data corresponding to the address of the arctangent calculation ROM 19.

FIG. 5 is a characteristic diagram showing the characteristic of the phase detection circuit. In the figure, 14A and 15A are the transmission phase shift values of the RF device 2 corresponding to the quantized I signal and the quantized Q signal of FIG. A curve showing the relation of the quantization numbers, 19 is the RF device transmission phase shift value taken as the horizontal axis of the graph, and 20 is the quantization number taken as the vertical axis of the graph. Here, the curve 14A is a cosine curve and the curve 15A is a sine curve, and the absolute values of their amplitudes are drawn equally.

Next, the operation will be described. In order to obtain the transmission phase shift value of the RF device 2, a part of the device input 1 input to the RF device 2 is taken out as a first monitor signal 4, and this is taken out by a distributor 5 for equal phase and equal power.
Divide into one signal. These two signals are referred to as an I channel LO signal 6 and a Q channel LO signal 7, respectively.

On the other hand, a part of the device output 3 which is the output of the RF device 2 is taken out as the second monitor signal 8,
The 90 degree hybrid 9 divides this into two signals of 90 degree phase difference and equal power. These two signals are I
The channel RF signal 10 and the Q channel RF signal 11 are used.

It is assumed that the phase of the Q channel RF signal 11 is delayed by 90 degrees with respect to the I channel RF signal 10. That is, I channel RF signal 10 = I _RF Q channel RF signal 11 = Q _RF Crest value of each signal = K Transmission phase shift value of RF device 2 = θ Signal angular frequency = ω Time = t, I _RF = K · cos (ω · t + θ) Q _RF = K · cos (ω · t + θ−90 °) = K · sin
(Ω · t + θ).

Next, in the I channel mixer 12, the I channel LO signal 6 and the I channel RF signal 10 are multiplied. It should be noted that both the I-channel mixer 12 and the Q-channel mixer 13 are treated as having a low-pass filter and an A / D converter built in the output stage (generally an IF port), and the explanation is simplified.

That is, the quantized I signal 14 output from the I channel mixer 12 is the I channel LO signal 6 =
Let I _LO = H · cos (ω · t), where H is the peak value of the I channel LO signal 6 and E = constant, the value V _I of the quantized I signal 14 is V _I = I _LO I _RF = H · K / 2 · {cos [ω · t + (ω · t + θ)] + cos [ω · t− (ω · t + θ)]} = E · cos (2 · ω · t + θ) + E · cos (− θ) ≈ E · cos (θ).

On the other hand, in the Q channel mixer 13, the Q channel LO signal 7 and the Q channel RF signal 11 are multiplied, and the quantized Q signal 15 output from the Q channel mixer 13 is the Q channel LO signal 7 = Q. _LO = I _LO =
Assuming that H · cos (ω · t), the value V _Q of the quantized Q signal 15 is V _Q = Q _LO · Q _RF = H · K / 2 · {sin [ω · t + (ω · t + θ)] + sin [−ω · t + (ω · t + θ)]} = E · sin (2 · ω · t + θ) + E · sin (θ) ≈E · cos (θ)

Next, the value of the phase output 18 is written in advance in the arctangent calculation ROM 19 according to the following. That is, the addresses of the arctangent calculation ROM 19 are V _I and V _Q, and the value θ of the phase output 18 read at this time is θ =
arctan (V _Q / V _I ).

Therefore, when the quantized I signal 14 and the quantized Q signal 15 are used for addressing the arctangent operation ROM 19, the phase output 18 from the arctangent operation ROM 19 is RF.
The transmission phase shift value of the device 2 is output (strictly, the phase difference between the paths of the first monitor signal 4 and the second monitor signal 8 is included).

[0016]

Since the conventional phase detection circuit is configured as described above, the distributors 5 and 90 are used.
Degree of the phase of hybrid 9, unbalance including frequency characteristics of distribution ratio, and I channel mixer 12 and Q
The IF output offset, the conversion loss difference, the saturation level difference, and the frequency characteristic difference of the channel mixer 13 are all factors that increase the error of the phase output 18, especially at high frequencies.
The wideband system has a problem that the phase detection accuracy is significantly reduced.

The present invention has been made in order to solve the above-mentioned problems, and minimizes the increase in hardware, suppresses the influence of frequency characteristics, imbalance of each component, etc., and is highly accurate. The purpose is to obtain a phase detection circuit.

[0018]

A phase detection circuit according to the present invention uses a quantized I signal and a quantized Q signal output from an I-channel mixer and a Q-channel mixer as addresses, and a phase value measured in advance from a phase value ROM. Is to be output.

[0019]

The phase detection circuit according to the present invention is a quantized I signal detected when a frequency actually used is applied,
The quantized Q signal is used as the address of the phase value ROM, and the phase value that is actually measured is prepared in advance as the phase value to be read from this phase value ROM, and the circuit unbalance or the frequency characteristic is calibrated in actual use. Make it available as output.

[0020]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 to 15 and 18 correspond to those shown in FIG. 3, and therefore, duplicated description thereof will be omitted here.

Reference numeral 17 denotes a phase value ROM (phase value read only memory) to which the quantized I signal 14 and the quantized Q signal 15 are input, and 16 is connected as a part of the address of the phase value ROM 17. It is a conditional term. And
FIG. 3 is a data table showing storage data corresponding to the addresses of the phase value ROM 17.

FIG. 2 is a characteristic diagram showing the characteristic of the phase detection circuit. In the figure, 14B and 15B are curves corresponding to the transmission phase shift value and the frequency value of the RF device 2 and taking irregular values. , And there is only one set of values of the quantized I signal 14, 15 in the transmission phase shift value of the RF device 2.

Next, the operation will be described. The operation is the same as in the case of the description of the prior art described above, except that the imbalance of each component shown in the following item is taken into consideration. In addition,
Since the condition 16 has the frequency characteristic as the phase detection characteristic, the condition for obtaining the phase output 18 from the phase value ROM 17 is given as an address.

In the description of the operation, for example, the frequency characteristic and the imbalance of each component, the output of the distributor 5 is not equal in phase and power, and the output of the 90-degree hybrid 9 is 9.
I cannot keep the phase difference of 0 degree, and I channel mixer 12 and Q
When an imbalance occurs in which the conversion losses are not equal, the channel mixer 13 quantizes the I signal 1
4 and the quantized Q signal 15 are not as described in the prior art.

If the values of these quantized I signal and quantized Q signal are V _I and V _Q , then V _I = F (φ, f) V _Q = G (φ, f) Here, F and G represent an irregular function including the RF device transmission phase shift value φ and the frequency f (power p in some cases), and only one set of V is included in one set of φ and f. _I and V _Q correspond.

Therefore, the transmission phase shift value of the RF device 2 is set to θ.
Then, θ = arctan explained as the prior art
(V _Q / V _I ) does not hold.

Therefore, as means for obtaining the transmission phase shift value θ,
The addresses of the phase value ROM 17 are V _I , V _Q and f, and the transparent phase shift value θ of the phase output 18 read corresponding to these addresses is the reference phase shifter when V _I and V _Q are obtained. It suffices if it is stored so that the set value is used.

[0028]

As described above, according to the present invention, the quantized I signal and the quantized Q signal output from the I-channel mixer and the Q-channel mixer are used as addresses to output the phase values measured in advance from the arithmetic ROM. Since it is configured as described above, there is an effect that a highly accurate phase signal can be output without a large change in hardware.

[Brief description of drawings]

FIG. 1 is a block diagram showing a phase detection circuit according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of the quantization number and the RF device transmission phase shift value of the quantized I signal and the quantized Q signal in FIG.

FIG. 3 is a data table diagram showing stored data corresponding to addresses of the phase value ROM in FIG.

FIG. 4 is a block diagram showing a conventional phase detection circuit.

5 is a quantization-RF device transmission phase shift value characteristic diagram of the quantized I signal and the quantized Q signal in FIG. 3;

6 is a data table diagram showing stored data corresponding to addresses of the arctangent operation ROM in FIG. 4. FIG.

[Explanation of symbols]

1 Device Input 2 RF Device 3 Device Output 4 First Monitor Signal 5 Distributor 6 I Channel LO Signal (In-Phase Channel Local Port Signal) 7 Q Channel LO Signal (90 Degree Phase Difference Channel Local Port Signal) 8 Second Monitor signal 9 90 degree hybrid 10 I channel RF signal (in-phase channel high frequency signal) 11 Q channel RF signal (90 degree phase difference channel high frequency signal) 12 I channel mixer (in-phase channel mixer) 13 Q channel mixer (90 Degree phase difference channel mixer) 14 quantized I signal (quantized in-phase signal) 15 quantized Q signal (quantized 90 degree phase difference signal) 17 phase value ROM (phase value read only memory)

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[Procedure amendment]

[Submission date] January 5, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (1)

[Claims] 1. A part of a device input of a high frequency device is received as a first monitor signal, which is supplied with two in-phase / equal power in-phase channel local port signals and 9
A distributor for distributing the 0 degree phase difference channel local port signal and a part of the device output of the above high frequency device as a second monitor signal, which receives two in-phase channel heights of 90 degree phase difference and equal power. Frequency signal and 90
A 90-degree hybrid that distributes to the phase-difference channel high-frequency signal, and an in-phase channel mixer that multiplies and digitally converts the in-phase channel local port signal and the in-phase channel high-frequency signal to output a quantized in-phase signal. A 90-degree phase difference channel mixer for multiplying and digitally converting the 90-degree phase-difference channel local port signal and the 90-degree phase-difference channel high frequency signal, and outputting a quantized 90-degree phase-difference signal; A phase detection circuit comprising a signal and a quantized 90-degree phase difference signal as an address, and a phase value read-only memory that outputs a phase value measured in advance.