1、 ANSI/CEA Standard TV Receiving Antenna Performance Presentation and Measurement ANSI/CEA-774-B February 2009 Copyright Consumer Electronics Association Provided by IHS under license with CEA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-NOTICE Consumer Electroni
2、cs Association (CEA) Standards, Bulletins and other technical publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and o
3、btaining with minimum delay the proper product for his particular need. Existence of such Standards, Bulletins and other technical publications shall not in any respect preclude any member or nonmember of CEA from manufacturing or selling products not conforming to such Standards, Bulletins or other
4、 technical publications, nor shall the existence of such Standards, Bulletins and other technical publications preclude their voluntary use by those other than CEA members, whether the standard is to be used either domestically or internationally. Standards, Bulletins and other technical publication
5、s are adopted by CEA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, CEA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard, Bulletin or other technical publication. This CE
6、A Standard is considered to have International Standardization implication, but the International Electrotechnical Commission activity has not progressed to the point where a valid comparison between the CEA Standard and the IEC document can be made. This Standard does not purport to address all saf
7、ety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations before its use. (Formulated under the cognizance of
8、the CEAs R5 Antennas Committee.) Published by CONSUMER ELECTRONICS ASSOCIATION 2009 Technology Phone 800-854-7179; Fax 303-397-2740; Internet http:/; Email IEEE Standards: Institute of Electrical and Electronics Engineers, 445 Hoes Lane, Piscataway, New Jersey 08854-1331 USA; Tel: +1 732 981 0060;
9、Internet http:/www.ieee.org. 2.3 Definitions Antenna Directivity Pattern A plot of the horizontal radiation pattern of an antenna. CEA TV Antenna Selector Map Program A computer program that allows consumers to input their location and receive a listing of receivable terrestrial over-the-air TV sign
10、als along with recommendations for appropriate antennas with which to receive these signals. Consumers may access this program at www.AntennaWeb.org. Front to Back Ratio The ratio of an antennas maximum gain (front, 0) to the highest gain between 90 and 270 (back). Half Power Beam Width In a radiati
11、on pattern plot containing the direction of the maximum of a lobe, the angle between the two directions in which the radiation intensity is one-half the maximum value. Average Gain to Null Ratio The average gain to null ratio is the ratio of the average gain of all lobes within 3 dB of the maximum l
12、obe to the minimum null. 2.4 Symbols and Abbreviations GTEM Gigahertz Transverse Electromagnetic Mode NIST National Institute of Standards and Technology VSWR Voltage Standing Wave Ratio 2.5 Compliance Notation As used in this document “shall” and “must” denote mandatory provisions of the standard.
13、“Should” denotes a provision that is recommended but not mandatory. “May” denotes a feature whose presence does not preclude compliance, and implementation of which is optional. “Optional” denotes items that may or may not be present in a compliant device. 3 Required Antenna Manufacturer Antenna Spe
14、cifications Manufacturers of TV antennas covered under the CEA TV Antenna Selector Map Program, and its logo licensing program, are required to certify that antenna performance meets minimum specifications detailed in CEA-2028-A, Color Codes for Outdoor TV Receiving Antennas, for each antenna produc
15、t. Copyright Consumer Electronics Association Provided by IHS under license with CEA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-CEA-774-B 3For active antennas the following additional specifications are required: Maximum amplifier gain at 200 MHz in dB Maximum
16、 amplifier gain at 650 MHz in dB Noise Figure at maximum gain at 200 MHz in dB Noise Figure at maximum gain at 650 MHz in dB Amplifier type: split band or ultra-wideband FM trap: Yes or No. 4 Manufacturer Antenna Testing When testing TV antennas the reporting methods presented here shall be employed
17、, and the measurement techniques presented here or in IEEE Std 149-1979 shall be employed. 5 TV Test Channels An antenna must have a specification and shall be subject to test on TV channels 2, 4, 6, 7, 9, 11, 13, 14, 20, 26, 32, 38, 44, 50, 56, 62, and 69,iexcept as noted later in this section. If
18、an antenna is designed for less than all channel reception it must have a specification and shall be subject to test on the lowest and highest channels and all test channels included in the bandwidth for which operation is claimed, except as noted later in this section. In the VHF bands, channels up
19、per or lower to those specified above may be used if necessitated by local ambient signal conditions but shall vary by no more than +/- 4 MHz from the center of the channel and shall include the channels 2, 6, 7, and 13. In the UHF band channels upper or lower to the ones referenced above may be use
20、d if necessitated by local ambient signal conditions but shall vary by no more than +/- 10 MHz from the center of the channel and shall include channels 14 and 69.iSingle channel antennas must have a published specification and shall be subject to test on the channel for which operation is claimed.
21、Special purpose limited bandwidth antennas must have a published specification and shall be subject to test on the lowest and highest channels and all test channels included in the bandwidth for which operation is claimed (with the same frequency deviations indicated above for VHF and UHF). 6 Antenn
22、a Performance Presentation It shall be standard to present TV receiving antenna performance by: 1) Antenna Directivity Pattern and Half Power Beam Width 2) Antenna Front to Back Ratio 3) Average Gain to Null Ratio for antennas that employ an electrically steered null 6.1 Antenna Directivity Pattern
23、For multiple channel TV antennas: It shall be standard to show the horizontal (azimuth) directivity pattern for each test channel for which antenna operation is claimed. The pattern should be based on the antennas performance at the center frequency for each test channel. Each pattern shall be clear
24、ly labeled with the half power beamwidth (-3 dB) in degrees. Copyright Consumer Electronics Association Provided by IHS under license with CEA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-CEA-774-B 4For single channel TV antennas: It shall be standard to show th
25、e horizontal (azimuth) directivity pattern for the center frequency of the channel of operation. If further completeness is desired, the directivity pattern may also be shown at the low and high frequency ends of the channel of operation. For both multiple channel and single channel TV antennas: The
26、 vertical (elevation) directivity pattern may be shown for more detailed presentation. In this case, when using the standard procedure for obtaining the horizontal directivity pattern for a given antenna, sufficient points shall be taken so that all major lobes, nulls, and minor lobes of amplitude g
27、reater than -20 dB relative to the maximum lobe are presented. The directivity pattern shall be presented on a 360 polar plot using either an amplitude scale of 0 to 10, or a logarithmic dB scale. The amplitude of the maximum lobe shall be adjusted to equal 10 or the outer ring of a polar plot using
28、 a dB scale. It will be standard to present the directivity pattern using a relative power scale, either linear or logarithmic with a reference level clearly labeled. A deviation of +7/-(any) from the category specification in CEA-2028-A is allowed in this test for half power beam width on channels
29、2-6. A deviation of +5/-(any) from the category specification in CEA-2028-A is allowed in this test for half power beam width on channels 7-69.i6.2 Antenna Front to Back Ratio It shall be standard to present antenna front to back ratio in graphical form or optionally in tabular form showing measurem
30、ents performed at the center of each of the test channels for each TV band for which antenna operation is claimed. With 0 representing the maximum lobe heading, the front to back ratio is defined as the ratio of the maximum lobe (front) to the strongest lobe between 90 and 270 (back). It shall be st
31、andard to use dB units to represent the front to back ratio. If desired, additional units may be shown such as relative voltage or relative power. A deviation of +2 dB/-(any) dB from the category specification in CEA-2028-A is allowed in this test. 6.3 Antenna Gain Relative to Dipole It shall be sta
32、ndard to present antenna gain relative to a dipole in graphical form or optionally in tabular form showing measurements performed at the center of each channel and at the extreme frequencies of each of the test channels for each TV band for which antenna operation is claimed. If the relative gain va
33、riation is greater than 2 dB in any one channel of operation, such variation shall be clearly presented. The channel center gain value will be the recorded gain. It will be standard to use dB units to represent relative gain. If desired, additional units may be shown such as relative voltage or rela
34、tive power. If the graphical presentation is used, the actual measured values shall be clearly marked. A folded dipole or simple dipole resonant at each test channel, and operating at a VSWR of 1.3 or less, shall be used as the standard reference antenna in relative gain measurements. The gain calib
35、ration of the reference antenna shall be traceable to the National Institute of Standards and Technology (NIST). It shall be standard to represent gain in dB compared to a reference dipole (dBd) where the reference dipole has a gain of 0.0 dBd. 6.4 Average Gain to Null Ratio For antennas that use an
36、 electrically steered null to reduce multipath interference it shall be standard to present the ratio of the average gain of maximum lobes to the gain of the minimum null. It shall be Copyright Consumer Electronics Association Provided by IHS under license with CEA Not for ResaleNo reproduction or n
37、etworking permitted without license from IHS-,-,-CEA-774-B 5standard to present antenna average gain to null ratio in graphical form or optionally in tabular form showing measurements performed at the center of each of the test channels for each TV band for which antenna operation is claimed, with 0
38、 representing either the maximum lobe heading or a front heading designated by the manufacturer. The average gain to null ratio is defined as the ratio of the average of all lobes within 3dB of the maximum lobe to the minimum null. The antenna will be placed in an electrical state of the manufacture
39、rs choice to achieve the highest ratio on each test channel. It shall be standard to use dB units to represent the average gain to null ratio. If desired, additional units may be shown such as relative voltage or relative power. Since electrically steered antennas are normally controlled by an assoc
40、iated television receiver using the ANSI/CEA-909-A interface, the antenna manufacturer must supply or be able to describe a readily available means of controlling the antenna state so that the antennas electrical state remains constant as the antenna is tested. The control means must be available to
41、 the test operator in order to optimize antenna performance for each test. For purposes of qualifying for a reception color in CEA-2028-A the Average Gain to Null Ratio (Ga/Nu) will be treated the same as front to back ratio. 6.5 Antenna Impedance Required presentation of antenna impedance is limite
42、d to specifying the antennas desired load impedance as either 75 or 300. If a manufacturer wishes to make a more complete impedance presentation it shall be standard to present the antenna impedance in graphical form or optionally in tabular form showing measurements performed at the center of each
43、channel and at the extreme channels of the test channels for each band for which operation is claimed. Careful and proper matching procedures must be used in order to obtain the impedance data. If graphical presentation is used, the actual measured values shall be clearly marked. 7 Antenna Performan
44、ce Measurements 7.1 Antenna Directivity Pattern and Relative Gain Using either the antenna range or GTEM cell alternative described below the field strength or intensity at the receiving antenna shall be measured by a suitably calibrated commercially available detector operated according to the manu
45、facturers instructions. The calibration shall be traceable to NIST. For purposes of these tests the reference antenna gain shall be that of the maximum lobe when the reference antenna is rotated through 360 (unless the manufacturer of the reference antenna specifies a different approach). The standa
46、rd reference antenna shall be positioned such that its center of radiation coincides with the center of rotation of the test fixture and it shall be in the same location as the radiation center of the antenna under test. For directional antennas, the antenna under test may employ separate mounting p
47、ositions along the direction of the maximum lobe for channels 2-6, 7-13, and UHF in order to place the center of radiation in each band at the center of rotation. Measurement Alternative 1: Using Antenna Range - It shall be standard to mount the lowest portion of the receiving antenna under test at
48、least one wavelength (at the lowest test frequency) above ground. The test fixture shall be capable of rotating the antenna 360 and when testing directional antennas shall have a calibrated indicator of relative antenna pointing accurate to +/- 1. The electromagnetic field at the receiving antenna s
49、hall be homogeneous: that is, movement of a probing antenna (not in excess of one-eighth wave length long at the operating frequency) within an area extending a quarter wave length beyond the extremes in any direction of any operating element of the receiving antenna shall result in a signal variation of less than 2 dB. Special care in the selection of the test site and positioning of the transmitting antenna must be exe
