free download barcode font excel Figure 91 A heterodyne VHF dual-conversion receiver in Software

Make UPC-A Supplement 2 in Software Figure 91 A heterodyne VHF dual-conversion receiver

Figure 91 A heterodyne VHF dual-conversion receiver
Draw UPC Symbol In None
Using Barcode drawer for Software Control to generate, create UPC Symbol image in Software applications.
Reading UCC - 12 In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
Communications System Design
Universal Product Code Version A Generator In C#.NET
Using Barcode encoder for VS .NET Control to generate, create UPC-A Supplement 2 image in Visual Studio .NET applications.
UPC A Drawer In Visual Studio .NET
Using Barcode creator for ASP.NET Control to generate, create UPC A image in ASP.NET applications.
Communications System Design
GTIN - 12 Creation In VS .NET
Using Barcode creation for .NET framework Control to generate, create GTIN - 12 image in .NET framework applications.
GTIN - 12 Encoder In VB.NET
Using Barcode creation for .NET framework Control to generate, create UPC-A Supplement 2 image in .NET framework applications.
If the receiver is required to operate only within the HF region or below, then both the LNA and BPF2 could be dropped from the receiver design, as noise figure is not as important in this region because of massive natural and artificial noise generation This will decrease sensitivity, but will give more IMD immunity in a crowded HF spectrum MIXER1 will normally be subjected to high amplitude input signals, so a high compression point is mandatory to decrease mixer-generated intermodulation distortion This will generally demand a high-level diode double-balanced mixer (DBM) instead of an active mixer stage in this sensitive location And for decreased IMD generation, the RF signal into the DBM should be at least 10 dB less than that injected into the DBM s LO port Thus, a level 10 mixer could accept a maximum of 0 dBm at its RF input port before excessive IMDs became a problem; 15 to 20 dBm less RF would be even better, and would be needed for higher-quality, lower-distortion receivers DBMs have the added advantage that they suppress even-order LO and RF mixer-generated harmonic products, as well as the RF and LO frequencies themselves, at the IF output Attenuation of these frequencies is far from complete, however The diplexer, placed after the MIXER1 stage, will filter and pass the desired IF but, unlike other filters, it will stop other frequencies from entering the IF s bandwidth by absorption rather than reflection Reflection of the undesired frequencies such as LO harmonics, the sum of the RF and LO, and the IMD products would cause RF power to be sent back into the mixer, which would unbalance its diode ring (causing increased IMD), as well as adversely affecting the mixer s dynamic range and conversion loss Indeed, many viable receiver architectures may simply pad the output of the mixer so that these reflections are attenuated not only as they enter the pad, but also as they are reflected back into the mixer s IF port The pads lower the input/output VSWR by supplying the mixer with an almost pure 50 j0 ohm termination (pads placed at the RF port will, however, reproduce thermal noise, which would have normally been removed by the image filter, at the image frequency) A wideband, high-isolation amplifier may also be used at the mixer s output, as shown for the second IF strip, since this will permit all of the mixing products to pass through this amplifier, and, after filtering from a normal reflective IF filter (such as BPF6), the BPF will bounce much of the undesired signals back toward the sensitive IF port of the mixer However, these reflected signals will have been significantly attenuated by the reverse isolation of this wideband amplifier Nonetheless, the amplifier must have a high P1dB to linearly accept the sometimes high-powered out-of-channel signals that can occur, without producing significant distortion The LOs must generate low phase noise in order to mitigate BER and adjacent channel selectivity degradation This can be difficult in phase-locked loop based LOs, but is relatively easy in properly designed high-Q crystal oscillators (see Chap 4, Oscillator Design ) All oscillator-generated spurious signals must also be as low as possible to minimize receiver spurious responses The LO amplifiers are broadband types used to buffer the local
Encoding DataMatrix In None
Using Barcode generation for Software Control to generate, create Data Matrix ECC200 image in Software applications.
Print EAN-13 Supplement 5 In None
Using Barcode printer for Software Control to generate, create EAN13 image in Software applications.
Downloaded from Digital Engineering Library @ McGraw-Hill (wwwdigitalengineeringlibrarycom) Copyright 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website
Make Code 128C In None
Using Barcode creation for Software Control to generate, create Code 128B image in Software applications.
UPC Symbol Drawer In None
Using Barcode encoder for Software Control to generate, create GS1 - 12 image in Software applications.
Communications System Design
Code39 Encoder In None
Using Barcode maker for Software Control to generate, create ANSI/AIM Code 39 image in Software applications.
GTIN - 128 Maker In None
Using Barcode drawer for Software Control to generate, create GTIN - 128 image in Software applications.
Nine
Monarch Generator In None
Using Barcode generation for Software Control to generate, create Code 2 of 7 image in Software applications.
Bar Code Drawer In VS .NET
Using Barcode creator for ASP.NET Control to generate, create bar code image in ASP.NET applications.
oscillator from the mixer ports to minimize VSWR, and thus mixer-generated IMD, and to increase the oscillator s output power to the nominal levels to maintain the mixer s NF and conversion losses In design of this LO chain, the LO amplifiers can be overdriven for maximum power output and flatness, since the LO signal involves only a single frequency This means that no IMD will be generated, only harmonics, which are easily filtered out Both BPF3 and BPF4 are employed to reduce wideband noise, harmonics, and possibly any subharmonics that will be present in the oscillator s outputs Reduction of generated wideband noise improves the mixer s NF and the receiver s sensitivity, while harmonic suppression prevents a decrease in the mixer second-order intercept point (IP2) and the subsequent generation of increased LO second harmonics The first IF chain of the receiver will furnish some gain and filtering (certain first IFs may supply only filtering), along with delayed AGC of any amplifiers present, before injection into MIXER2 If desired, this first IF filtering of the DIPLEXER and BPF6 will also remove the second image frequency from reaching MIXER2, but the filtering itself must not be so tight as to introduce excessive group delay variations, causing increased BER The filtering is present mainly to provide some channel selectivity and the rejection of spurious signals, since image noise into MIXER2 is not a concern if relatively high gain stages are adopted in the receiver s front end, which is where the NF is set (the noise floor at MIXER2 will be mainly noise amplified by the LNA) The second IF amplifiers and filter stages supply most of the receiver s gain and selectivity, since lower-frequency circuits are cheaper and more stable However, any such high-gain IF stages should be shielded against EMI that may have been emitted from other internal stages, or from external emissions, in order to prevent amplifier oscillations and receiver interference The second IF strip will also increase the receiver s total dynamic range by the use of variablegain amplifiers (VGAs) within an AGC loop This automatic gain control will not only control the gain of the second IF stages but, with many high-end receivers, it will also set the gain of the first IF strip and the LNA The second IF strip will output fOUT into an external modem, or into an internal detector stage
UPCA Generation In Java
Using Barcode creation for BIRT Control to generate, create UPC Code image in BIRT reports applications.
Barcode Creation In Java
Using Barcode generation for Java Control to generate, create barcode image in Java applications.
UPC-A Supplement 5 Maker In None
Using Barcode printer for Microsoft Excel Control to generate, create UPC-A Supplement 2 image in Office Excel applications.
Barcode Recognizer In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
Bar Code Scanner In Visual Basic .NET
Using Barcode Control SDK for .NET framework Control to generate, create, read, scan barcode image in .NET framework applications.
Creating UPC-A In None
Using Barcode generation for Word Control to generate, create UCC - 12 image in Microsoft Word applications.
Copyright © OnBarcode.com . All rights reserved.