Mixer

RF系统中的模型混频器

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RF.Blockset / Circuit Envelope / Elements

Description

这Mixerblock performs signal frequency translation and nonlinear amplification.

对于给定的RF输入信号，V._RF.=一种_RF.CO.s(ω_RF.T）和一个输入信号V._LO=一种C_LOCO.s(ω_LOT）那T.he mixer multiplies the signals at the input ports:

$\begin{matrix} {V.}_{一世n} {V.}_{LO} = {一种}_{一世n} CO.s （ ω_{一世n} T. 的） {一种}_{LO} CO.s （ ω_{LO} T. 的） \\ = \frac{{一种}_{一世n} {一种}_{LO}}{2} CO.s [（ ω_{一世n} + ω_{LO} 的） T.] + \frac{{一种}_{一世n} {一种}_{LO}}{2} CO.s [（ ω_{一世n} - ω_{LO} 的） T.] \end{matrix}$

该混合将RF信号的频率转换为ω_RF.+ω_LO一种ndω_RF.-ω_LO。对于混频器正确执行此操作，必须包含频率ω_RF.+ω_LOO.rω_RF.-ω_LO一世n the simulation frequencies the配置块计算。

该块的功率增益规范将单边带（SSB）的功率涉及输入。

混合RF和LO信号后，混频器块执行放大。为了模拟线性放大，混频器通过系数缩放信号一种₁。一种V.O.ltage Controlled Voltage Source (VCVS), specified with a polynomial, implements nonlinear amplification. The polynomial includes saturation automatically and produces additional intermodulation frequencies.

Mixerblock mask icons are dynamic and indicate the current state of the applied noise parameter. This table shows you how the icons on this block vary based on the state of the噪音figure (dB)parameter on the block.

噪音figure (dB):`10.`	噪音figure (dB):`0.`

参数

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Main

`转换增益来源`— Source parameter of conversion gain
`可用功率增益`（默认）|`Open circuit voltage gain`|`多项式系数`

转换增益的源参数，指定为以下之一：

可用功率增益- 该块使用可用功率增益参数的值来计算多项式VCV的线性电压增益项，a₁。This calculation assumes a matched load termination for the mixer.
Open circuit voltage gain— The block uses the value of the Open circuit voltage gain parameter as the linear voltage gain term of the polynomial VCVS, a₁。
多项式系数- 块根据您指定的多项式实现非线性电压增益。多项式的顺序必须小于或等于9，并且系数被排序为上升功率。如果矢量A有10系数，[一种_0.那一种₁那一种₂那…,一种_9.]，它代表的多项式是V._O.ut=一种_0.+一种₁V._一世n+一种₂V._一世n²+⋯ +一种_9.V._一世n^9.。In this case,一种₁表示线性增益术语，并且根据的更高阶项的建模是根据的[1]。
FO.r example, the vector [一种_0.那一种₁那一种₂那一种_3.)指定的关系V._O.ut=一种_0.+一种₁V._一世n+一种₂V._一世n²+⋯ +一种_3.V._一世n^3.。
Trailing zeroes are omitted: if一种_3.= 0，[一种_0.那一种₁那一种₂]将相同的多项式定义为[一种_0.那一种₁那一种₂，0]。此参数的默认值为[0 1]，对应于线性关系V._O.=V._一世。

`可用功率增益`— Linear gain of mixer
0.`D b`（默认）|标量

Linear gain of mixer, specified as a scalar in dB. Specify the units from the corresponding drop-down list.

依赖性

To enable this parameter, select可用功率增益一世n转换增益来源T.一种b.

`Open circuit voltage gain`- 开路电压增益
0.`D b`（默认）|标量

Open circuit voltage of mixer, specified as a scalar in dB. Specify the units from the corresponding drop-down list.

依赖性

To enable this parameter, selectOpen circuit voltage gain一世n转换增益来源T.一种b.

`多项式系数`- 多项式的顺序
`[0 1]`（默认）|向量

Order of polynomial, specified as a vector.

这O.rder of the polynomial must be less than or equal to 9. The coefficients are ordered in ascending powers. If a vector has 10 coefficients,[一种_0.那一种₁那一种₂，......一种_9.]，它代表的多项式是：

V._O.ut=一种_0.+一种₁V._一世n+一种₂V._一世n²+。。。+一种_9.V._一世n^9.

在哪里一种₁represents the linear gain term, and higher-order terms are modeled according to[1]。

FO.r example, the vector[一种_0.那一种₁那一种₂那一种_32.]指定关系V._O.=一种_0.+一种₁V.₁+一种₂V.₁²+一种_3.V.₁^3.。省略尾随零。如果一种_3.= 0，然后[一种_0.那一种₁那一种₂]将相同的多项式定义为[一种_0.那一种₁那一种₂那0.]。默认值O.f this parameter is [0,1], corresponding to the linear relationV._O.=V._一世。

依赖性

To enable this parameter, select多项式系数一世n转换增益来源T.一种b.

`输入阻抗（欧姆）`— Input impedance of mixer
`50.`（默认）|标量

混频器的输入阻抗，指定为标量。

`输出一世mpedance (Ohm)`— Output impedance of mixer
`50.`（默认）|标量

输出一世mpedance of mixer, specified as a scalar.

`LO impedance (Ohm)`— Impedance at LO port of mixer
`一世nf`（默认）|标量

输出一世mpedance of mixer, specified as a scalar.

`噪音figure (dB)`- 单边带IEEE噪声系数的混音器
0.`D b`（默认）|标量

混频器的单边带噪声系数，根据IEEE指定为标量^®定义。

用a模拟电路包络模型的噪声噪音那一种mplifier，要么Mixerblock, you must select the模拟噪音Check box in the配置块对话框。

IEEE SSB定义假设混合器输入的图像带宽中的噪声完全拒绝，而混频器内部在图像带宽和信号带宽中产生噪声。结果，混频器输出的噪声是两个贡献的总和：

${N.}_{O.ut} = {N.}_{一世n} G_{混合} + 2 {N.}_{混合器} G_{混合} 那$

在哪里：

N._O.ut一世s the noise at the output of the mixer.
N._一世n一世s the noise at the input of the mixer (assuming that the noise in the image bandwidth is perfectly rejected).
N._混合器一世s the noise internally generated by the mixer in both the signal and the image bandwidths.
G_混合一世s the mixer gain.

一种s a result, the noise factor according to the IEEE SSB definition can be expressed as

$F_{SSB-IEEE.} = 1 + 2 {N.}_{混合器} / {N.}_{一世n} 那$

这与其他常用定义有关

$\begin{matrix} F_{SSB} = 2 + 2 {N.}_{混合器} / {N.}_{一世n} = 1 + F_{SSB-IEEE.} 那 \\ F_{DSB} = 1 + {N.}_{混合器} / {N.}_{一世n} = \frac{1}{2} （ 1 + F_{SSB-IEEE.} 的）。 \end{matrix}$

You can apply the IEEE SSB definition directly to describe mixer stages when using the Friis formulas for link budget analysis. Using the other definitions requires changing the Friis formulas. Both theMixerrf blockset™中的块和RF.Budget Analyzer应用程序在RF Toolbox™中使用IEEE定义。

这一种nalytic relationships between the three definitions allow you to simulate the noise level at the output of the mixer. For example,

$\begin{matrix} F_{SSB} = 4. D b \Rightarrow F_{SSB-IEEE.} = 10. \log_{10.} （ {10.}^{F_{SSB} / 10.} - 1 的） = 1。79 D b 那 \\ F_{DSB} = 4. D b \Rightarrow F_{SSB-IEEE.} = 10. \log_{10.} （ 2 \times {10.}^{F_{DSB} / 10.} - 1 的） = 6.04 D b 。 \end{matrix}$

如果you simulate an RF Blockset mixer without including an ideal image rejection filter, then the noise at the output of the mixer is larger than that predicted by the noise figure, because the noise in the image bandwidth is effectively folded onto the output signal.

FO.r this reason, when generating models, both theModulator一种ndDemodulatorblocks insert an ideal image-rejection filter automatically. (You can remove the filtering within the block mask.)

这噪声系数试验台block measures the SSB noise figure and enables you to verify that the simulated noise figure has the expected value.

如果将理想的映像抑制滤波器添加到模型中，则有效噪声系数与分析值一致。
如果you remove the image-rejection filter, or if you use a filter with partial rejection, then the measured noise figure is larger than the analytic value.

`地面并隐藏负端子`— Ground RF circuit terminals
`O.n`（默认）|`O.ff`

选择此参数到内部地面并隐藏负端子。要公开负端子，请清除此参数。通过曝光这些终端，您可以将它们连接到模型的其他部分。

By default, this option is selected.

非线性

`非线性多项式类型`- 多项式非线性
`偶数和奇数`（默认）|`Odd order`

多项式非线性，指定为以下之一：

偶数和奇数：当你选择时偶数和奇数那T.he amplifier can produce second- and third-order intermodulation frequencies in addition to a linear term.
Odd order：当你选择时Odd order那T.he amplifier generates only odd order intermodulation frequencies.
这linear gain determines the linear一种₁T.erm. The block calculates the remaining terms from the specified parameters. These parameters areIP3那1-DB增益压缩功率那输出saturation power那一种nd增益压缩在土星一种T.一世O.n。您指定的约束次数确定模型的顺序。该图显示了非线性混频器参数的图形定义。

`Intercept points convention`- 拦截点公约
`输出`（默认）|`Input`

Intercept points convention, specified asInput-referred or输出-referred. Use this specification for the intercept points, 1-dB gain compression power, and saturation power.

`IP2`- 二阶拦截点
`一世nfD bm`（默认）|标量

Second-order intercept point. specified as a scalar. The default value一世nfD bmCO.rresponds to an unspecified point.

依赖性

To enable this parameter, select偶数和奇数一世n非线性多项式类型T.一种b.

`IP3`- 三阶拦截点
`一世nfD bm`（默认）|标量

三阶拦截点，指定为标量。默认值一世nfD bmCO.rresponds to an unspecified point.

`1-DB增益压缩功率`— 1-dB gain compression power
`一世nfD bm`（默认）|标量

1-DB增益压缩功率那specified as a scalar. The 1-dB gain compression point must be less than the output saturation power.

依赖性

To enable this parameter, selectOdd order一世n非线性多项式类型T.一种b.

`输出saturation power`— Output saturation power
`一世nfD bm`（默认）|标量

输出saturation power, specified as a scalar. The block uses this value to calculate the voltage saturation point used in the nonlinear model. In this case, the first derivative of the polynomial is zero, and the second derivative is negative.

依赖性

To enable this parameter, selectOdd order一世n非线性多项式类型T.一种b.

`增益压缩在土星一种T.一世O.n`— Gain compression at saturation
`一世nfD bm`（默认）|标量

增益压缩在土星一种T.一世O.n, specified as a scalar.

依赖性

To enable this parameter, selectOdd order一世n非线性多项式类型T.一种b and set输出saturation power。

模型例子

使用复杂信号验证IP2 / IP3

使用射频Blockset™电路包络图书馆run a two-tone experiment that measures the second- and third-order intercept points of an amplifier. The model computes the intercept points of the amplifier from the modulated signal power measured on each carrier, verifying the behavior of the RF Blockset system. These values are confirmed using the RF Budget Analyzer app and a measurement testbench.

热噪声对通信系统性能的影响

Use the RF Blockset™ Circuit Envelope library to model thermal noise in a super-heterodyne RF receiver and measure its effects on a communications system noise figure (NF) and bit error rate (BER). A Communications Toolbox™ reference model with parameters computed using Friis equations and a RF Blockset Noise Testbench are used to verify the results.

Compatibility Considerations

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混音器块图标更新

Behavior changed in R2021b

Starting in R2021b, theMixerblock icon has updated. The block icons are now dynamic and show the current state of the noise parameter.

当您打开r2021b之前创建的模型时Mixer块，软件使用R2021B版本替换块图标。

References

[1] Grob，Siegfried和Jürgenlindner。“非线性放大器的多项式模型推导。”Department of Information Technology那University of Ulm, Germany.

也可以看看

一种mplifier|S-Parameters

Introduced in R2010b

Mixer

Description

参数

`转换增益来源`— Source parameter of conversion gain
`可用功率增益`（默认）|`Open circuit voltage gain`|`多项式系数`

`可用功率增益`— Linear gain of mixer
0.`D b`（默认）|标量

依赖性