* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download 1 - Telecommunications Industry Association
Automatic test equipment wikipedia , lookup
Analog television wikipedia , lookup
Broadcast television systems wikipedia , lookup
Direction finding wikipedia , lookup
Wien bridge oscillator wikipedia , lookup
Amateur radio repeater wikipedia , lookup
Radio direction finder wikipedia , lookup
Resistive opto-isolator wikipedia , lookup
Opto-isolator wikipedia , lookup
Telecommunication wikipedia , lookup
Rectiverter wikipedia , lookup
Analog-to-digital converter wikipedia , lookup
Regenerative circuit wikipedia , lookup
405-line television system wikipedia , lookup
Mathematics of radio engineering wikipedia , lookup
Equalization (audio) wikipedia , lookup
Phase-locked loop wikipedia , lookup
Oscilloscope history wikipedia , lookup
Tektronix analog oscilloscopes wikipedia , lookup
Index of electronics articles wikipedia , lookup
Valve RF amplifier wikipedia , lookup
Radio transmitter design wikipedia , lookup
Spectrum analyzer wikipedia , lookup
Radio broadcasting wikipedia , lookup
Proposed change/modification Document Number: TR-41.9.2-04-02-013-R1 Document Number: TR-41.9.2-02-11-010 STANDARDS PROJECT: TR41.9.2 - TSB31-C, Section 9.16 Non-LADC Metallic Voltage - 4 kHz to 30 MHz updates TITLE: Proposal to revise TSB31-C, Section 9.16 Non-LADC Metallic Voltage 4 kHz to 30 MHz test procedures ISSUES ADDRESSED: Update TSB31-C, Section 9.16. Added to the comments test method for TIA-968-A, sections 4.5.7.3 (Through Transmission from Other Equipment) and 4.5.7.4 (Music on Hold, Out Of Band). SOURCE: Cisco Systems CONTACTS: Tim Lawler, Cisco Systems, e-mail: [email protected] DATE: February 24, 2004 DISTRIBUTION TO: TIA TR-41.9.2 (TSB-31-C working group) KEYWORDS: TIA-968-A Non-LADC Metallic Voltage - 4 kHz to 30 MHz test procedures NOTICE: The contributor grants a free, irrevocable license to the Telecommunications Industry Association (TIA) to incorporate text or other copyrightable material contained in this contribution and any modifications thereof in the creation of a TIA Publication; to copyright and sell in TIA's name any TIA Publication even though it may include all or portions of this contribution; and at TIA's sole discretion to permit others to reproduce in whole or in part such contribution or the resulting TIA Publication. This contributor will also be willing to grant licenses under such copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing a TIA Publication which incorporates this contribution. This document has been prepared by Cisco Systems to assist the TIA Engineering Committee. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on Cisco Systems. Cisco Systems specifically reserves the right to amend or modify the material contained herein and nothing herein shall be construed as conferring or offering licenses or rights with respect to any intellectual property of Cisco Systems other than provided in the copyright statement above. 9.16 Non-LADC Metallic Voltage - 4 kHz to 30 MHz TIA-968-A, 4.5.5.1 9.16.1 Background This requirement ensures that spurious or unintended signals transmitted from terminal equipment at frequencies above voiceband do not interfere with telephone company transmission systems or services that function at such frequencies. The most limiting situations are those that involve subscriber multichannel analog carrier systems. These are systems that are used in the local exchange plant to obtain a wire pair gain advantage. In these systems, the signals to and from several subscribers are multiplexed onto a wire pair using frequency division. Each direction of transmission for each subscriber uses either 4 kHz (single sideband) or 8 kHz (double sideband) of frequency spectrum. Generally, the carrier systems most susceptible to crosstalk are those that use double sideband modulation methods, 8 kHz of spectrum for each direction of transmission per channel. Accordingly, the requirements in TIA-968-A are specified in 8 kHz bands relative to the center frequency of each band. Thus the limits in each band are based on the susceptibility of the affected analog multichannel carrier system, crosstalk characteristics of the wire pair cable facilities, and the characteristic terminating impedance of the cable facilities. The limit is therefore established for each 8 kHz band centered in the frequency specified in the tables up to 270 kHz. The 100-millisecond averaging time for frequencies less than 270 kHz approximates the minimum time necessary for the interfering signal to affect the transmission performance of subscriber analog carrier systems on other cable pairs. For frequencies greater than 270 kHz, a 2-microsecond averaging time is specified. This averaging time is approximately the reciprocal of the Nyquist rate of "T" carrier. It represents the time interval appropriate to interference with the "T" carrier transmission. Such a signal duration will result in pulse interference and consequently transmission errors. One broadband requirement above 270 kHz is adequate. 9.16.2 Purpose To verify that the EUT does not apply excessive out-of-band power to the PSTN. 9.16.3 Equipment (1) Applicable loop simulator SEL# 4. (2) Bandpass filter SEL# 9 (3) Digital sampling storage oscilloscope SEL# 24. (4) Spectrum analyzer SEL# 34 NOTE: Refer to Section 4.3 for equipment details. 9.16.4 Equipment States Subject to Test (1) On-hook. (2) All active operating states. 9.16.5 Procedure NOTE: See comments (1), (2), (3) and (6) before performing tests. (1) Connect the EUT to the test circuit of Figure 9.16-1. (2) Place the EUT in the on-hook state. (3) Select R1 to be 300 ohms. (4) Measure the energy in each 8 kHz band whose center frequency is in the range of 8 kHz to 12 kHz, and record the results. (5) Select R1 to be 135 ohms. (6) Measure the energy in each 8 kHz band whose center frequency is in the range of 12 kHz to 90 kHz, and record the results. (7) Measure the energy in each 8 kHz band whose center frequency is in the range of 90 kHz to 266 kHz and record the worst case result. (8) Place the EUT in each of its off-hook states as specified in TIA-968-A Section 4.5.7.2, and condition the EUT as specified in TIA-968-A Section 4.5.7.3 or 4.5.7.4, as appropriate (see comment 7 and 8). (9) Repeat step (3) through step (7) at minimum and maximum loop currents attainable with the loop simulator, if applicable. (10) Connect the EUT to the test circuit of Figure 9.16-2, and set the passband of the filter to measure broadband energy in the frequency range 270 kHz to 30 MHz (see comment 4 and 5). (11) Condition the EUT to the on-hook state. (12) Set the digital oscilloscope to provide: (a) 2 µs per sample; (b) Trigger at -25 dBV; (c) Accumulate mode; (d) Vertical scale 0 mV to 250 mV full height. NOTE: If the baseline contains 1000 points then a single trace will take 2 ms. (13) Program the oscilloscope to accumulate 10 traces. (14) Record the value of the largest peak measured and convert to V rms by multiplying by 0.707. (15) With the EUT in each of its active operating states as specified in TIA-968-A Section 4.5.7.2, condition the EUT as specified in TIA-968-A Section 4.5.7.3 or 4.5.7.4, as appropriate (see comment 7 and 8). (16) Repeat step (13) and step (14) at minimum and maximum loop currents attainable with the loop simulator, if applicable. 9.16.6 Alternative Method - Broadband Procedure NOTE: See comments (2), (3), and (5). (1) Connect the EUT to the test circuit of Figure 9.16-1. (2) Place the EUT in the on-hook state. (3) Select R1 to be 300 ohms. (4) Set the spectrum analyzer to measure broadband energy in the frequency range 4 kHz to 16 kHz, using the required termination, and record the result. (5) Select R1 to be 135 ohms. (6) Set the spectrum analyzer to measure broadband energy in the frequency range 8 kHz to 94 kHz, and record the result. (7) Set the spectrum analyzer to measure broadband energy in the frequency range 86 kHz to 270 kHz, and record the worst case result. (8) Set the spectrum analyzer to measure broadband energy in the frequency range 270 kHz to 6 MHz, and record the worst case result. (9) Set the spectrum analyzer to measure broadband energy in the frequency range 6 MHz to 30 MHz, and record the worst case result. (10) Place the EUT in each of its off-hook states as specified in TIA-968-A Section 4.5.7.2, and condition the EUT as specified in TIA-968 Section 4.5.7.3 or 4.5.7.4, as appropriate (see comment 7 and 8). (11) Repeat step (3) through step (9) at minimum and maximum loop currents attainable with the loop simulator, if applicable. (12) If the test results obtained in step (4) and step (6) through step (9) do not exceed the maximum limits specified in TIA-968 Section 4.5.5.1, then no further tests are required (see comment 2). 9.16.7 Suggested Test Data (1) Center frequencies. (2) Start and stop frequencies. (3) Measured or calculated signal power values. (4) Equipment state. 9.16.8 Comments When using a detector that measures individual frequency components, the following procedure should be employed. (1) Total the voltages which are within 6 dB of the specified limit in each consecutive band. If the sum of these voltages exceeds the limits, recheck the measurement at a frequency centered over the band with the apparent failure. The total rms voltage can be calculated using the expression: Vt = (V12 + V22 + . . . + Vn2 )0.5 NOTE: This expression assumes that the spectral components have random phase relationships. (2) The broadband measurement procedure may be used for the purpose of economy of measurement. If the value obtained is lower than the most restrictive limit specified for that frequency range, then the signal levels in 8 kHz bands in that range will be lower than that specified for the most restrictive 8 kHz band. However, the main procedure of Section 9.16.5 should be used when the requirements are not met as the signal levels in each band may still be within specified limits. Refer to TIA-968-A Section 4.5.5.1. (3) If a spectrum analyzer is used and it does not have an 8 kHz bandwidth, a 10 kHz bandwidth may be used. Application of a correction factor, additional measurements, or both, may be required to compensate for the wider bandwidth. (4) If a failure condition is noted when a 10 kHz bandwidth is used and the spectral content has uneven distribution, it may be necessary to check that reading, using a higher resolution. (5) The total rms voltage over an 8 kHz band can be calculated using the expression: Vt = (V12 + V22 + . . . + Vn2 )0.5 where Vt is the total rms voltage over any 8 kHz band and V1, V2, V3....Vn are the spectral components within that band that are within 20 dB of the limit for the band in question. NOTE: This expression assumes that the spectral components have random phase relationships. If the spectral content of a band is evenly distributed, then the equivalent rms power in an 8 kHz band can be found by subtracting 1 dB from the measured power using a 10 kHz bandwidth. Since this is a measurement of a metallic (balanced) circuit, the only ground connection should be that of the line cord of the oscilloscope or spectrum analyzer. (6) See TIA-968-A Section 4.5.7.2 through 4.5.7.4 for the conditions that apply for different equipment types. (7) For approved terminal equipment or protective circuits with provision for throughtransmission from other equipment, apply a 1000 Hz signal from a 600 ohm source that results in a power output of -13 dBm delivered into a 600 ohm load at the network interface. (8) The EUT input test levels and frequencies that should be used in testing protective circuits for compliance with all out-of-band frequencies are as follows: (a) For approved data protective circuits, apply a 1000 Hz signal that is 10 dB higher then the overload point. (b) For approved terminal equipment or approved protective circuits with nonapproved signal source input, such as music on hold, apply an input signal (white noise) with a frequency range of 200 Hz to 20 kHz and the level set at the overload point. NOTES: (1) Select the appropriate loop simulator for the interface of the EUT. (2) Loop current is measured with a current meter in series with R2 of the loop simulator. Refer to the figures of Section 1 of TIA-968-A. (3) The resistor shown (R1) is connected in place of R1 as shown in the loop simulator drawing. The resistor has a value of 300 Ohms for frequencies of 4 kHz to 12 kHz and 135 Ohms for frequencies of 12 kHz to 30 MHz. Capacitor C1 of the loop simulator should be capable of coupling the frequencies covered by this test. (4) The spectrum analyzer should provide a balanced input, or an isolation transformer or balun transformer may be used. FIGURE 9.16-1. NON-LADC METALLIC 4 KHZ TO 30 MHZ NOTES: (1) Select the appropriate loop simulator for the interface of the EUT. (2) Loop current is measured with a current meter in series with R2 of the loop simulator. Refer to the figures of Section 1 of TIA-968-A. (3) The resistor shown (R1) is connected in place of R1 as shown in the loop simulator drawing. The resistor has a value of 135 Ohms. Capacitor C1 of the loop simulator should be capable of coupling the frequencies covered by this test. (4) The oscilloscope should provide a balanced input, or an isolation transformer or balun transformer may be used. FIGURE 9.16-2. NON-LADC METALLIC 270 KHZ TO 30 MHZ