I hope it is not too late to wish all c9h9y9nians a Happy New Year. May the 2009 be a prosperous year for us. Sorry for not actively blogging over the past few couple of months. I hope I can post more frequently in 2009.
06
Nov
Reload ‘n Win Contest
Poster
Ni lagi sekali dikatakan rezeki….tak disangka-sangka, c9h9y9 telah terpilih utk memenangi hadiah saguhati (Touch ‘n Go card bernilai RM 100) utk pertandingan ni…siapa nak bgk..lepas lah tol pegi balik shah alam utk 15 hari…alhamdulillah…
Tak sesia tampal sticker ni…tips utk semua, pastikan sticker ni ditampal di setiap sisi kereta…hahahaha…terima kasih PLUS !!!
Utk senarai pemenang ada kat sini. c9h9y9 di senarai yg ke-149.
From its conception in 1943 by Dr. Rudolf Kompfner in England, and later its development by Kompfner and John R. Pierce at the Bell Laboratories in the United States, the travelling wave tube (TWT) has become the microwave amplifier of choice for many commercial and military systems. Originally developed for communication, these devices have become fundamental to many military applications, including radar, electronic counter measures (ECM) and electronic warfare (EW) systems.
In simple terms all types of TWTs consist of an electron gun, a slow wave structure, magnetic focussing system, RF input and output couplers, and a collector. With operating voltages applied, the electron gun (containing an emitter) produces an electron beam, which is injected into the slow wave structure (SWS).
The magnetic focussing system constrains the electron beam, allowing it to travel longitudinally down the centre of the slow wave structure.
RF power of the appropriate frequency is injected through the input coupler onto the slow wave structure. The electron beam and the RF signal travel down the structure at similar speeds and an interaction between the two results in an energy transfer from the electron beam into the electromagnetic wave, thus achieving an amplification in the RF signal. The collector at the opposite end of the device to the electron gun is designed to collect the spent electron beam and dissipate the remaining energy efficiently.
Sources:
1. Microwave Journal
2. Wikipedia
9M2RPN Calling OR4ISS
Seramai 16 orang pelajar Tahun Empat dari pelbagai sekolah seluruh negara telah dipilih untuk berkomunikasi dengan Richard Garriot menerusi radio amatur selama sembilan minit di stesyen bumi mikrosatelit, 9M2RPN di Planetarium Negara, KL. Program khas tersebut turut disaksikan oleh Mejar Dr. Faiz Khaleed, c9h9y9 dan mike.
Pelbagai soalan diajukan kepada Richard berhubung pengembaraan beliau ke ISS.
Salah satu soalan yang diajukan oleh murid dari Sekolah Jenis Kebangsaan Cina (SJKC) Chi Wen, Labuan, Shaun Ho Ee Farn, adakah beliau berpeluang untuk menikmati kejadian siang dan malam ketika berada di ISS.
Richard menjelaskan, kejadian siang dan malam bertukar sebanyak 16 kali kerana ISS berpusing mengelilingi orbit.
Seorang lagi murid dari SJKC Chung Hwa Kota Kinabalu , Sabah, Nicholas Yeoh, pula ingin mengetahui tempoh perjalanan beliau dari bumi ke angkasa lepas.
Garriott menjawab, perjalanan tersebut sangat singkat yang hanya memakan masa selama lapan minit sahaja.
“Saya hanya mengelap badan sahaja bagi tujuan membersihkan badan selama berada di ISS,” katanya ketika ditanya murid dari Sekolah St Edmund Limbang, Cosmartin Allistair, semasa siaran secara langsung menerusi radio amatur dijalankan di Planetarium Negara.
Selain itu, Garriot turut menyatakan, saiz matahari yang dilihat dari ISS adalah sama seperti melihatnya dari permukaan bumi tetapi ia kelihatan lebih terang jika dilihat dari ISS.
Terdahulu beliau telah diterbangkan ke ISS menerusi roket Soyuz pada 12 Oktober lalu dan pulang ke bumi pada 22 Oktober.
Sumber: Utusan Malaysia
Multiple In, Multiple Out (MIMO) techniques are becoming a popular combination with OFDM radio formats because they offer the possibility of increased spectral efficiency. The first commercially available MIMO system was in WLAN, but the interest has spread to cellular formats including WiMAX and LTE. Each format has adopted slightly different techniques and terminology, sometimes making it a little difficult to be sure what is being discussed.
What is MIMO
MIMO systems also introduce a new dimension in test - that of the cross coupling of signals between hardware transmit and receive paths. This gives rise to new performance measurement techniques to augment the single channel tests that remain the starting point.
Related sites of interest:
1. www.agilent.com/find/MIMO
2. WLAN 802.11n implementation of MIMO
3. WiMAX Implementation of MIMO
4. LTE Implementation of MIMO
