Adaptive differential pulse-code modulation (ADPCM) is a variant of differential pulse-code modulation (DPCM) that varies the size of the quantization step, to allow further reduction of the required bandwidth for a given signal-to-noise ratio.

Typically, the adaptation to signal statistics in ADPCM consists simply of an adaptive scale factor before quantizing the difference in the DPCM encoder.^[1]

ADPCM was developed in the early 1970s at Bell Labs for voice coding, by P. Cummiskey, N. S. Jayant, and James L. Flanagan.^[2]

In telephony[link]

In telephony, a standard audio signal for a single phone call is encoded as 8000 analog samples per second, of 8 bits each, giving a 64 kbit/s digital signal known as DS0. The default signal compression encoding on a DS0 is either μ-law (mu-law) PCM (North America and Japan) or A-law PCM (Europe and most of the rest of the world). These are logarithmic compression systems where a 13 or 14 bit linear PCM sample number is mapped into an 8 bit value. This system is described by international standard G.711. Where circuit costs are high and loss of voice quality is acceptable, it sometimes makes sense to compress the voice signal even further. An ADPCM algorithm is used to map a series of 8 bit µ-law (or a-law) PCM samples into a series of 4 bit ADPCM samples. In this way, the capacity of the line is doubled. The technique is detailed in the G.726 standard.

Some ADPCM techniques are used in Voice over IP communications. ADPCM was also used by Interactive Multimedia Association for development of legacy audio codec known as ADPCM DVI, IMA ADPCM or DVI4, in the early 1990s.^[3]

Split-band or subband ADPCM[link]

G.722^[4] is a ITU-T standard wideband speech codec operating at 48, 56 and 64 kbit/s, based on subband coding with two channels and ADPCM coding of each.^[5] Before the digitization process, it catches the analog signal and divides it in frequency bands with QMF filters (quadrature mirror filters) to get two subbands of the signal. When the ADPCM bitstream of each subband is obtained, the results are multiplexed and the next step is storage or transmission of the data. The decoder has to perform the reverse process, that is, demultiplex and decode each subband of the bitstream and recombine them.

Referring to the coding process, in some applications as voice coding, the subband that includes the voice is coded with more bits than the others. It is a way to reduce the file size.

References[link]

1. ^ Ken C. Pohlmann (2005). Principles of Digital Audio. McGraw-Hill Professional. ISBN 978-0-07-144156-8. http://books.google.com/books?id=VZw6z9a03ikC&pg=PA122&dq=adpcm+adaptive+differential+pulse-code+modulation&ei=4KNNSdbVB4fEkATAorS7BA#PPA122,M1. 
2. ^ P. Cummiskey, N. S. Jayant, and J. L. Flanagan, "Adaptive quantization in differential PCM coding of speech," Bell Syst. Tech. J., vol. 52, pp. 1105—1118, Sept. 1973.
3. ^ Recommended Practices for Enhancing Digital Audio Compatibility in Multimedia Systems - legacy IMA ADPCM specification, Retrieved on 2009-07-06
4. ^ ITU-T G.722 page ITU-T Recommendation G.722 (11/88), "7 kHz audio-coding within 64 kbit/s"
5. ^ Jerry D. Gibson, Toby Berger, and Tom Lookabaugh (1998). Digital Compression for Multimedia. Morgan Kaufmann. ISBN 978-1-55860-369-1. http://books.google.com/books?id=aqQ2Ry6spu0C&pg=PA265&dq=G.722+adpcm+subband+split&lr=&as_brr=3&as_pt=ALLTYPES&ei=VqFNSfbxB5CIkATU4LjJCQ. 

Emma Bunton
Bunton at Britains Pride Event 2011
Background information
Birth name	Emma Lee Bunton
Also known as	Baby Spice
Born	(1976-01-21) 21 January 1976 (age 36) Finchley, London, England
Origin	London, England
Genres	Pop, adult contemporary
Occupations	Singer-songwriter TV and radio presenter
Years active	1994–present
Labels	Virgin (1996–2007) Polydor (2003–04) 19 (2004–07) (US) Universal Music (2004–07)
Associated acts	Spice Girls
Website	emmabuntonofficial.com

Emma Lee Bunton (born 21 January 1976) is a British pop singer/songwriter and TV and radio presenter. She was a member of the 1990s girl group, the Spice Girls, in which she was known as Baby Spice as she was the youngest member. In 2010, she joined the judging panel on ITV's Dancing on Ice. She is also the host of Heart FM Saturday afternoon drive-time slot.

Her debut solo album A Girl Like Me was released in the United Kingdom on 16 April 2001 by Virgin Records. The album debuted and peaked at number four on the UK Albums Chart. On 7 September 2001, A Girl Like Me was certified gold by the British Phonographic Industry for sales in excess of 100,000 copies,^[1] ultimately becoming the 147th best-selling album in the UK for 2001.^[2] The album brought the UK number-one "What Took You So Long?" as well as top five hits "What I Am" (a cover of a 1988 song by Edie Brickell & New Bohemians) and "Take My Breath Away" and the top 20 hit "We're Not Gonna Sleep Tonight". The album sold 125,000 copies in the UK.

Bunton's second album, Free Me, was released in 2004 through 19 Entertainment/Universal Records. Four singles were taken from it: "Free Me", "Maybe", "I'll Be There" and "Crickets Sing For Anamaria". The album spent over twelve weeks inside the UK Albums Chart, peaking at number seven and selling over 141,712 copies, earning gold award status. After Free Me and Maybe were released as singles and had success in the American dance charts, the album was released in North America.^{[citation needed]}

Biography[link]

1976–92: Early life and career beginnings[link]

Bunton was born in Finchley, North London, brought up as a Catholic, and grew up in Woodside Park.^[3] Her parents, Pauline, a karate instructor, and Trevor, a milkman, split up when she was 11, after which she stayed with her mother. She has a younger brother, Paul James.^[4] Bunton went to St. Theresa's Primary School in Finchley, then to Sylvia Young Theatre School in Marylebone.^{[citation needed]} She appeared briefly in the BBC series EastEnders in 1992 as a mugger.^[5] In 1993, she appeared in the ITV1 police series, The Bill, and also made a brief appearance as a prostitute in the BBC drama series To Play the King. After appearing on the show she was offered a temporary role as a troubled prostitute trying to kick her drug habit, but she turned it down because she wanted to maintain a wholesome image.^{[citation needed]} Bunton also appeared in a public information film for the British government concerning fire safety.^[6]

1993–2000: Spice Girls[link]

She joined the Spice Girls (then called Touch) in 1993 after Michelle Stephenson left.^{[citation needed]} Bunton was called Baby Spice because she was the youngest, had long blonde pigtails, wore babydoll dresses and had a girly girl personality.^{[citation needed]}

The debut single Wannabe was the first of nine number ones in the United Kingdom for the Spice Girls, and reached the top in 37 countries.^{[citation needed]} As a songwriter, Bunton set the shortest time to achieve six No.1 UK singles, one year and five months from Wannabe to Too Much.^{[citation needed]} In 1999, she presented Emma on VH1. She recorded "(Hey You) Free Up Your Mind" for the film Pokémon: The First Movie.

[edit] 2001–05: A Girl Like Me and Free Me

Her debut solo album A Girl Like Me, released in the United Kingdom on 16 April 2001 by Virgin Records. The album debuted and peaked at number four on the UK Albums Chart, with 21,500 copies sold in its first week. Although initial success was promising, A Girl Like Me fell down the chart quickly. However, singles "What Took You So Long?", "Take My Breath Away", and "We're Not Gonna Sleep Tonight" helped the album stay on the UK Albums Chart for several weeks. On 7 September 2001, A Girl Like Me was certified gold by the British Phonographic Industry for sales in excess of 100,000 copies,^[1] ultimately becoming the 147th best-selling album in the UK for 2001.^[2] Lacklustre sales may be partially explained by the fact that the album was not released in Latin America (except in Brazil, Argentina, and Chile) and North America. The album brought the UK number-one "What Took You So Long?" as well as top five hits "What I Am" (a cover of a 1988 song by Edie Brickell & New Bohemians) and "Take My Breath Away" and the top 20 hit "We're Not Gonna Sleep Tonight". The album sold 125,000 copies in the UK.^{[citation needed]} Disappointing sales led to Bunton's leaving Virgin in 2002.^[7]

Bunton's second album, Free Me, was released in 2003 through 19 Entertainment/Universal Records. Four singles were taken from it: "Free Me", "Maybe", "I'll Be There" and "Crickets Sing For Anamaria". After success in the American dance charts the album was sold in North America.^{[citation needed]} The American edition included remixes and a different cover.^{[citation needed]} The album was the second to follow her 2001 release, A Girl Like Me, and spent over twelve weeks inside the UK Albums Chart, peaking at number seven and selling over 141,712 copies, earning gold award status. The album was widely acclaimed by critics as being the "one of best solo Spice records ever" due to its catchy and fun use of sounds from the Motown and the 1960s era. The album was largely produced by Mike Peden and Yak Bondy, who have produced tracks for S Club 7 and Lucie Silvas, to name a few. Other contributions on the album courtesy of Cathy Dennis, Henry Binns and Puerto Rican singer Luis Fonsi. "One Thing I Know", an unreleased track co-written by Bunton for Free Me, was recorded by another 19 Management act, S Club 8, for their album Sundown. Bunton's original vocals can clearly be heard on S Club 8's version.

The lead single, "Free Me", was released in the spring of 2003. The song immediately picked up airplay, and the single sold well in the UK, peaking at number five on the UK Singles Chart. "Maybe" was released as the second single in the autumn of 2003, and also gained extensive airplay throughout the UK, peaking at number six, one position lower than its predecessor.

In the spring of 2004, the album and its third single, "I'll Be There", were released. The single, like its two predecessors, performed well on the charts, peaking at number seven, one position below "Maybe", and two positions below "Free Me". The album sold more copies in its first week then her debut solo record had, and would ultimately go on to outsell it by 25,000 copies. With this, Bunton became the only Spice Girls member to have sold more copies of her second album than her first in UK. Later in the year, the fourth single, "Crickets Sing for Anamaria", was released. Despite its harder beat and grittier sound, by now the impact of Free Me was beginning to wear off, and the song only came in at number fifteen on the UK Singles Chart, totalling 25,000 copies, and becoming Bunton's lowest-selling single.

In the U.S., both "Free Me" and "Maybe" were dance club regulars, reaching number four and number six on the U.S. Billboard Hot Dance Club Play respectively. In 2005, Bunton filmed guest roles in two Bollywood films: Pyaar Mein Twist and Chocolate: Deep Dark Secrets.^{[citation needed]}

[edit] 2006–08: Life in Mono and return of the Spice Girls

Bunton performing during the return of the Spice Girls tour in 2007

In October 2006, Bunton was a contestant in the BBC programme Strictly Come Dancing, partnered by Darren Bennett. She finished third place in the final.^{[citation needed]}

In November 2006, Bunton released the charity single for the BBC Children in Need appeal, recording Petula Clark's 1960s song "Downtown". It reached number three on the UK Singles Chart and was followed by her third studio album, Life in Mono on 4 December.^{[citation needed]} The album was originally set for a November release in the UK, however it was later pushed back to 4 December 2006. Life In Mono, much like her previous album, Free Me, experimented with elements of 1960s pop music. For this particular album the musical arrangement was more directed towards the '60s French pop music, with some elements of British '60s pop and Motown. The first single taken from the album was a cover of Petula Clark's 1964 hit single "Downtown", released on 13 November. "Downtown" is the 2006 BBC Children in Need official charity single and reached No.3 in the UK singles chart. "All I Need to Know" was released as second single.

Bunton had been working on her third release since winter 2004. The album's title track is a cover version of the hit "Life in Mono" by 1990s trip hop band Mono, best known through its usage in the 1998 film Great Expectations. The track "Take Me to Another Town" contains a sample from Herb Alpert's 1965 "Green Peppers". Due to Emma’s pregnancy all forms of promotion were cancelled after a few months. Rumours of a third single surfaced through sites after Emma stated she was thinking of releasing a third single, however this never came. The songs I Wasn’t Looking (When I Found Love), Perfect Strangers and Take Me To Another Town were rumoured.

Although it sold almost 13,000 copies in its first week, the album was Emma's first not to reach the UK Top 10. It debuted on the UK Albums Chart at No.65 on 10 December 2006 falling to No.75 in its second week and dropped out of the chart the following week. On the whole, the album sold around 60,000 copies in the UK. The album entered the UK Albums Chart at 65, selling 13,000 copies in its first week.^{[citation needed]} The second single from it was "All I Need to Know", on 12 February 2007, intended for Valentine's Day. Bunton shot the video around Old Street in East London, in the week before Christmas 2006.^[8] Entering the UK Singles Chart at 60, "All I Need to Know" became the lowest-charting single of Bunton's solo career.^{[citation needed]}

Bunton has been seen in a television commercial for the supermarket chain Tesco. She also had a cameo role on the Australian soap opera Neighbours on the episode titled "What's a Spice Girl Like You...?", aired on 19 March 2007 in Australia, and on 25 May 2007 in the UK.^{[citation needed]} Bunton returned to US screens with a nationwide commercial for Prego in May 2007.^{[citation needed]}

In July 2008, Bunton stood in as co-presenter alongside Richard Madeley on the UK television show Richard & Judy while Judy Finnigan was recovering from a knee operation. In October 2008, Bunton appeared on the UK series of The X Factor to assist judge Dannii Minogue in choosing the three best over-25s acts to take to the live X Factor finals. In December 2008, Bunton debuted as a member of the panel on Loose Women on ITV.^{[citation needed]}

2009–present: Television and radio work[link]

In February, and again between May and June 2009, she starred as guest presenter on Heart London's Heart Breakfast alongside Jamie Theakston and Harriet Scott.^[9] Bunton began hosting her own pre-recorded Saturday drive time ^[10] radio show on Heart in the Saturday afternoon slot 4pm – 7pm starting on Saturday 13 June 2009.^[11]

In January 2010, Emma joined the "Ice Panel" on ITV dancing show Dancing on Ice replacing former judge Ruthie Henshall. She stepped down from this role on 2 December 2011 in order to pursue new projects.^{[citation needed]} In February 2010, Bunton appeared in a UK National Television campaign first aired during Coronation Street,^[12] showing her in the Heart Radio studios at the start and the end of the advert. In summer 2010, she presented the Five program Don't Stop Believing.

In August 2010 she guest presented GMTV with Lorraine on GMTV. On 8 October 2010,^[13] 19 November 2010 and 7 January 2011,^[14] she guest presented Lorraine on ITV Breakfast. Bunton is providing maternity leave cover for Heart Breakfast co-presenter Harriet Scott from 3 October until 23 December 2011 on Heart London.^[15] On January 2012, Bunton reprised her role as one of fictional PR manager Edina Monsoon's disgruntled clients in a revival of the BBC's Absolutely Fabulous.

Personal life[link]

Bunton's long-term partner since 2000 is former Damage and CherryBlackStone lead singer Jade Jones. Bunton – after being proposed to on 21 January 2011, the day of her 35th birthday – announced her engagement to Jones during an episode of Dancing on Ice on 23 January 2011.^[16] The couple have two sons: Beau Lee Jones born on 10 August 2007 at the Portland Hospital in London,^[17] and Tate Lee Jones born on 6 May 2011.^[18]

Filmography[link]

Film

Television

• ¹: Emma presented the program Richard & Judy while Judy Finnigan was recovering from a knee operation.
• ²: Emma stood in for Fearne Cotton as a team captain as Fearne was absent for the episode.
• ³: Emma stood in for Holly Willoughby as a team captain as Holly was absent for the episode.

Radio

Discography[link]

• 2001: A Girl Like Me
• 2004: Free Me
• 2006: Life in Mono

References[link]

External links[link]

Wikimedia Commons has media related to: Emma Bunton

• Official website
• Emma Bunton at the Internet Movie Database