CN101006652A - Device for noise reduction - Google Patents
Device for noise reduction Download PDFInfo
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- CN101006652A CN101006652A CN 200580024167 CN200580024167A CN101006652A CN 101006652 A CN101006652 A CN 101006652A CN 200580024167 CN200580024167 CN 200580024167 CN 200580024167 A CN200580024167 A CN 200580024167A CN 101006652 A CN101006652 A CN 101006652A
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Abstract
A device is for reducing noise in a radio receiver, which comprises a transformer (30) having a reference voltage input (20), a radio signal input at a first transformer side, and a radio signal output at a second transformer side, an A/D converter (40) being connected to said second transformer side, wherein a first bandpass filter (50) is connected between said second transformer side and said A/D converter.
Description
Technical field
The present invention relates to be used for radio base station, the radio receiver of (3G) mobile communication system that is used in particular for the third generation.More specifically, the present invention relates to a kind of device that is used for the noise of filter radio signals before conversion from the analog signal to the digital signal.
Background technology
From such as by standard A MPS (Advanced Mobile Phone System, Advanced Mobile Phone System) and NMT (Nordic Mobile Telephone, NMT) the initial analogue system of Ding Yi those begins, in the past few decades, cellular telephone industry has in the world had huge development.In several years in the past, this development almost all concentrates on the standard of digital solutions of cellular radio network systems, for example D-AMPS (for example, defined in EIA/TIA-IS-54-B and IS-136) and GSM (GlobalSystem for Mobile Communications, global system for mobile communications), it is commonly referred to as second generation mobile communication system.
Current, cellular technology is just entering the third generation (also being expressed as 3G).WCDMA (Wideband Code Division Multiple Access, Wideband Code Division Multiple Access (WCDMA)) is 3G air interface (air-interface) technology of extensive employing in new IMT-2000 frequency band up to now.By 3GPP (Third Generation PartnershipProject, third generation partnership projects) and ITU (international TelecommunicationUnion, International Telecommunications Union) standardization, WCDMA has won extensive approval in wireless communication industry.By 2005, estimating will have near 100 WCDMA networks in the world in running.
In WCDMA, user data is propagated on the bandwidth of about 5MHz.Because frequency diversity, wide bandwidth supports high user data rates and performance advantage also is provided.Yet, system user can with the accurate data transmission speed and be not easy the prediction.Mobile network's actual capacity is subjected to influence of various factors, and for example weather condition, current how many users are by public base station communication and most important, the distance between customer mobile terminal and the antenna for base station.In the term of WCDMA, radio base station is known as Node B.
Radio base station comprises the radio receiver that is designed for from being connected to the base station or receiving radio signals with antenna that the base station is integrated together.Before handling the radio signal that is received, radio signal is by from the analog-converted to the numeral.Under the situation of WCDMA, the radio signal of input has the frequency of about 1920-1980MHz.Yet the A/D converter that is used in usually in the radio receiver has quite little bandwidth (usually less than 700MHz).Therefore, before signal is provided to A/D converter, need carry out frequency inverted.For this reason, between radio receiver circuit and A/D converter, adopt front-end circuit, usually with the fixed intermediate frequency that is mixed down under the frequency input signal in the 100-300MHz scope.This intermediate frequency is by being used for providing to the input of A/D converter the transformer conduction of reference voltage.A/D converter has the sample frequency that is lower than intermediate frequency, is generally 30-100MHz.
Partly and schematically show the prior art solution of radio receiver circuit, wherein, receive the radio signal of input from the left side among Fig. 1.Provide reference voltage at 20 places for transformer 30.Transformer 30 is connected to A/D converter 40.In order to eliminate or to suppress the noise such as disturbance or interference from analog radio signal, band pass filter 10 is connected before the transformer usually.Yet although have been found that band pass filter 10, it usually is not enough that noise reduces.
Summary of the invention
General objective of the present invention is, a kind of radio receiver solution with improved inhibition noise ability of comparing with the prior art solution is provided.According to a first aspect of the invention, the device of the noise by being used for reducing radio receiver has been realized this target, and radio receiver comprises: transformer has reference voltage input terminal; The radio signal input is positioned at first transformer side; The radio signal output is positioned at second transformer side; And A/D converter, be connected to described second transformer side, wherein, between described second transformer side and described A/D converter, be connected with first band pass filter.
In one embodiment, second band pass filter is connected to described first transformer side, and the unwanted Nyquist (Nyquist) that is used for suppressing before described transformer from the radio signal that is received is distinguished.
In one embodiment, described first band pass filter is designed to suppress common-mode noise.
In one embodiment, described first band pass filter is designed to suppress differential mode noise.
In one embodiment, described receiver is designed to the frequency inverted of input radio signal is fixing intermediate frequency, and described A/D converter has the sample frequency less than half of described intermediate frequency, and wherein, described first band pass filter has the bandwidth less than half of described intermediate frequency.
In one embodiment, described second transformer side is connected to described A/D converter by two lead-in wires, and wherein, described first band pass filter comprises that the capacitive character between described two lead-in wires connects.
In one embodiment, described first band pass filter comprises that the inductive between described two lead-in wires connects.
In one embodiment, described first band pass filter comprises the resistive load on each bar in described two lead-in wires.
The capacitive character of each bar in one embodiment, described first band pass filter comprises from ground to described two lead-in wires connects.
Description of drawings
With reference to the accompanying drawing description of preferred embodiments, it is more apparent that the features and advantages of the present invention will become, wherein by following
Fig. 1 has schematically shown the prior art solution of the noise reduction that is used for radio receiver;
Fig. 2 shows the block diagram of the embodiment that comprises the band pass filter on the transformer outlet side; And
Fig. 3 shows the embodiment of described band pass filter.
Embodiment
Fig. 2 has schematically shown the embodiment of the device of the noise reduction that is used for radio receiver.The left side of the radio signal that is received from figure is input to first transformer side of transformer 30.Second transformer side outputs to A/D converter 40 with the radio signal of transformation.Transformer 30 is used to A/D converter 40 subsequently that reference voltage is provided, and wherein, reference voltage provides (not shown) at 20 places by voltage source.
According to the present invention, first band pass filter 50 is arranged between second side, outlet side and the A/D converter 40 of transformer 30.Because the bandwidth of the radio signal that need change in A/D converter 40 is usually less than 10MHz, so preferably, filter 50 has the bandwidth less than half of the sample frequency of A/D converter 40, and in one embodiment, the sample frequency of A/D converter 40 is approximately 30-100MH.Have been found that by band pass filter 50 being arranged on the outlet side of transformer and being located immediately at before the A/D converter 40, improved the noise reduction.Reason to this is considered to, by the prior art solutions shown in Fig. 1, and transformer 30 and still can pick up capacitive character that does not need frequency and inductive couplings disturbance in other Nyquist districts to transformer with from the lead-in wire of transformer.And these disturbances can existing common mode have the differential mode characteristic again.Therefore, by band pass filter 50 is set after transformer 30, can be reduced in the disturbance of picking up in the transformer, and by band pass filter 50 is provided with as close as possible A/D converter 40, and by minimizing the lead-in wire that can pick up filter noise afterwards, the noise that obtains to optimize reduces.
In one embodiment, second band pass filter 10 can also be used in transformer 30 fronts, and this optional feature is represented by the chain-dotted line profile of band pass filter among Fig. 2 10.
Fig. 3 has schematically shown the design that is arranged on the band pass filter 50 between transformer 30 and the A/D converter 40, and alternatively, second band pass filter 10 is positioned at before the transformer.Band pass filter 50 receives two barss lead-in wire from transformer 30.Preferably, inductive connection L is set and is connected C1 between two lead-in wires with capacitive character.In addition, two lead-in wires preferably are connected to ground by capacitive character connection C2.Filter 50 can also comprise the resistance element R on the every lead-in wire.
The typical component values of the embodiment of the invention and span are shown in the following table.
| Element | Impedance ranges | Typical impedance |
| C 1 | 5-7pF | 6pF |
| C 2 | 35-45pF | 40pF |
| L | 10-30nH | 22nH |
| R | 45-55ohm | 51ohm |
The invention provides a kind of improved solution that is used for reducing the noise of radio receiver, typically can be applicable in the base station in the WCDMA network, but be not limited to this field.The present invention is only defined by the appended claims.
Claims (9)
1. be used for reducing the device of the noise of radio receiver, described radio receiver comprises: transformer has reference voltage input terminal; The radio signal input is positioned at first transformer side; And the radio signal output, be positioned at second transformer side; A/D converter is connected to described second transformer side, wherein, is connected with first band pass filter between described second transformer side and the described A/D converter.
2. device according to claim 1, wherein, described first transformer side is connected with second band pass filter, is used for before described transformer suppressing the unwanted Nyquist district from the radio signal that is received.
3. device according to claim 1 and 2, wherein, described first band pass filter is designed to suppress common-mode noise.
4. each described device in requiring according to aforesaid right, wherein, described first band pass filter is designed to suppress differential mode noise.
5. each described device in requiring according to aforesaid right, wherein, described receiver is designed to the frequency inverted of input radio signal is fixing intermediate frequency, and described A/D converter has the sample frequency less than half of described intermediate frequency, wherein, described first band pass filter has the bandwidth less than half of described intermediate frequency.
6. each described device in requiring according to aforesaid right, wherein, described second transformer side is connected to described A/D converter by two lead-in wires, and wherein, described first band pass filter comprises that the capacitive character between described two lead-in wires connects.
7. device according to claim 6, wherein, described first band pass filter comprises that the inductive between described two lead-in wires connects.
8. according to claim 6 or 7 described devices, wherein, described first band pass filter comprises the resistive load on each bar in described two lead-in wires.
9. according to each described device in the claim 6 to 8, wherein, the capacitive character of each bar described first band pass filter comprises from ground to described two lead-in wires connects.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52182804P | 2004-07-08 | 2004-07-08 | |
| SE04017950 | 2004-07-08 | ||
| US60/521,828 | 2004-07-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101006652A true CN101006652A (en) | 2007-07-25 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200580024167 Pending CN101006652A (en) | 2004-07-08 | 2005-07-05 | Device for noise reduction |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104807537A (en) * | 2014-01-28 | 2015-07-29 | 恩智浦有限公司 | Noise sensor |
-
2005
- 2005-07-05 CN CN 200580024167 patent/CN101006652A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104807537A (en) * | 2014-01-28 | 2015-07-29 | 恩智浦有限公司 | Noise sensor |
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