GPS中C/NO(dB-hZ)是什么意思

allanwang

各位兄弟，谁知道GPS中C/NO(dB-hZ)是什么意思．我搞GPＳ时间不长，所以不怎么了解，希望各位不要见外

jianxinliu

C/No是载波功率和噪声功率之比

allanwang

谢谢这个兄台指点.但是为什么它后面带(dB-hZ).一般都是以dB为单位的,有没有这方面的资料,可以发一点过来看看吗?[/COLOR]

52Gold

dBm 1 milliwatt (.001W), Typical measurement for audio input/output specifications. Also used in low power optical transmitter specifications.

dBm(600) The standard audio reference power level defined by 1 milliwatt measured with respect to a 600 ohm load. This measurement is commonly used in broadcasting, professional audio applications and is a common telephone communications standard.

dBm(50) This standard is defined by 1 milliwatt measured with respect to a 50 ohm load. This measurement is commonly used in RF transmissions/receiving systems.

dBm(75) This standard is defined by 1 milliwatt measured with respect to a 75 ohm load. This standard is common in some RF systems particularly cable TV systems.

dBmW This is the generic form for a 1 milliwatt reference, also written as dBm. This term usually has an inferred load reference, depending on the application.

dBW This is a common form for power amplification relative to a 1 watt reference (usually 50 ohms). Typical applications are found in RF Power Amplifiers and High Power Audio Amplifiers specifications.

dBuV This is a common form for specifying input RF levels to a communications receiver. This is called dB microvolt where 1 microvolt = 1*10E-6V.

dbV While this dB term is defined, it is rarely used in defining communication systems. The dB value is obtained with respect to 1 Volt.

dB/bit This is a common term used for specifying the dynamic range or resolution for a Pulse Coded Modulation (PCM) system such as a CD player. This reference is defined by 20 Log(2)/bit = 6.02dB/bit.

dBi This is dB isotropic . It is used as the reference when defining Antenna Gain.

dB/Hz This is relative noise power in 1-Hz bandwidth. This term is used often in digital communications and in defining a laser's Relative Intensity Noise (RIN). For a laser system, this is an electrical not an optical measurement. A typical1 RIN for a semiconductor laser is -150 dB/Hz.

dBW/K-Hz This is a common term used when analyzing carrier-to-noise (C/N) in a communications link such as a satellite link budget. This value is based on the Boltzmann's constant expressed in dB as 10 Log(1.38*10E-23) = -228.6 dBW/K-Hz.

allanwang

谢谢52Gold的解释,现在有些了解了

[em14]

liufes

由于GPS为扩频调制，信号在噪声以下，不能用SNR来表示。
噪声的能量是正比于带宽的，要用dBm/Hz来表示能量密度。
在频谱分析仪上明显可以看出，RBW每减小10倍，噪底降低10dB。

yxy7826

GPS/WLAN/BT都属于宽带调制，但是也不是不能用SNR来表示GPS信号的衰减程度。

allanwang

有没有这方面的资料?能发过来看看和交流一下吗?[em14]