This document specifies the procedures to test implementations
\nof SMV-compatible variable-rate speech codecs either by meeting
\nthe bit-exact implementation, or meeting recommended minimum
\nperformance requirements<\/i>. This speech codec is the Service
\nOption 56 described in TIA-893-1. The Service Option 56 speech
\ncodec is used to digitally encode the speech signal for
\ntransmission at variable data rates of 8550, 4000, 2000, or 800
\nbps. Like some other speech coding standards, this standard
\nprovides a bit-exact method of testing the codec for minimum
\nperformance. In this optional procedure, a given set of test
\nvectors are input to the test codec, and the output vectors from
\nthe test codec must be bit-exact with the output vectors generated
\nfrom the Software Distribution which is part of this standard. If
\nthey are bit-exact, the codec passes the minimum performance
\nrequirement and no further testing is required. The bit-exact mode
\nof testing, however, is only applicable to codecs whose design
\nconforms in all respects to the algorithmic description of the SMV
\nin TIA-893-1, including either of the noise suppression options and
\neither of the voice activity detection options. These options are
\ndescribed in TIA-893-1. The bit-exact SMV validation includes
\nspecific testing of the OEM SMV to the frame erasure processing
\ncharacteristics of the standard SMV. Should the candidate SMV
\ndiffer in any of these components, the codec shall be tested using
\nthe objective and subjective tests prescribed by this standard.
\nThat is, SMV compliance of a "test codec" can be achieved by
\neither:<\/p>\n
\u2022 demonstrating bit-exactness according to the procedure
\ndescribed in Section 3.6, specifically Sections 3.6.5.1 to 3.6.5.4,
\nor<\/p>\n
\u2022 following the objective and subjective testing procedures set
\nforth in Sections 2.1 and 2.2 of this standard, using processes
\nadditionally defined in Section 3.6, specifically Sections 3.6.5.5
\nto 3.6.5.8.<\/p>\n
With the exception of Section 3.6, the remaining text applies
\nonly to implementations that do not satisfy the requirement for
\nbit-exactness.<\/p>\n
Testing the codec is based on two classes of procedures:
\nobjective tests and subjective tests. In the event that the test
\ncodec fails any of the objective or subjective tests, the test
\ncodec fails the compliance test. Objective tests are based upon
\nactual measurements from the speech codec function. Subjective
\ntests are based on listening tests to judge overall speech quality.
\nThe minimum subjective requirement for the test codec is based upon
\nthe ability of the test codec to demonstrate performance equivalent
\nto or better than that of the SMV floating-point master codec
\nwithin a fixed allowable statistical error.<\/p>\n
The purpose of the testing is not only to ensure adequate
\nperformance between one manufacturer's encoder and decoder but also
\nthat this level of performance is maintained with operation between
\nany pairing of manufacturers' encoders and decoders. This
\ninteroperability issue is a serious one. Any variation in
\nimplementing the exact standard must be avoided if it cannot be
\nensured that minimum performance levels are met when
\ninter-operating with all other manufacturers' equipment meeting the
\nstandard. This standard provides a means for measuring performance
\nlevels while trying to ensure proper interoperation with other
\nmanufacturers' equipment.<\/p>\n
The issue of interoperation can only be definitively answered by
\ntesting all combinations of encoder\/decoder pairings. With the
\nnumber of equipment manufacturers expected to supply equipment,
\nthis becomes a prohibitive task; therefore, the objective and
\nsubjective tests rely upon the use of a "master codec". The master
\ncodec is defined as the floating-point implementation of TIA-893-1
\nwritten in the C-programming language.<\/p>\n
The master codec software, described in 3.4, is used as part of
\nthe interoperability testing. The master er codec is available in
\nan associated Software Distribution as part of TIA-893-1.<\/p>\n
By convention in this document, the Courier font is used to
\nindicate C-language and other software constructs, such as file and
\nvariable names.<\/p>\n","protected":false},"excerpt":{"rendered":"
Selectable Mode Vocoder Minimum Performance Specification – Option 56 for Wideband Spread Spectrum Digital Systems<\/b><\/p>\n\n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n TIA<\/b><\/a><\/td>\n 2005<\/td>\n NA<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":0,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2646],"product_tag":[],"class_list":{"0":"post-691964","1":"product","2":"type-product","3":"status-publish","5":"product_cat-tia","7":"first","8":"instock","9":"sold-individually","10":"shipping-taxable","11":"purchasable","12":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/691964","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=691964"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=691964"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=691964"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}