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EE Times – 10 Projects Showcasing the Raspberry Pi\’s Versatility.

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10 Projects Showcasing the Raspberry Pi’s Versatility

TechNews 科技新報 – Chromecast 已被破解 核心為特製版 Android.

Chromecast 已被破解 核心為特製版 Android

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Google 新發表的 Chromecast 電視棒以 35 元低廉的價格,讓使用者輕易的插上電視就可以用來播放網路內容的構想,在發表後馬上引發各方消費者的興趣,雖然其功能有所限制,不過在各方努力的逐一挖掘下,發現 Chromecast 的未來各種應用的潛力可能比 Google 所設定的還要多。

 

Google 的 Chromecast 原本的設計是讓使用者在電視串流播放網路內容的產品,是無法播放任何在電腦、平板或手機上的內容,除非先把內容上傳到網路上,而唯一可以同步畫面方式的就只有 Chrome 瀏覽器,因為瀏覽器本來就是觀看網路的內容,因此可以做到如同同步畫面般的功能(其實只是各自同時抓取來自網路的內容)。

不過,現在已有使用者發現,只要在電腦的 Chrome 瀏覽器中先行安裝 Google Cast 這個延伸套件,就可以用來播放存放在電腦中的內容,比如說影片。而且播放過程很簡單,只要把影片所在的路徑貼到 Chrome 中,才按下「Cast this tab to…」就可以播放出去了。

Screen-Shot-2013-07-25-at-8.44.55-AM-650x437

▲透過 Chrome 的延伸套件,Chromecast 也可以播放電腦中的影片

 

對玩家來說,僅僅播放在電腦中是難以滿足的,因此有玩家就直接 Root 進 Chromecast 的核心,並發現 Chromecast 的系統核心並非來自 Chrome OS,反而是接近 Google TV,採用的是特製版的 Android 系統。

由於採用了 Android 系統,因此可以預想得到在經過權限設定與軟體開發的配合下,Chromecast 其實是可以擁有許多的可能,或許可以直接做到如同 AppleTV 一樣直接播放電腦中的影片,而不光只是網路的內容串流。

▲Chromecast 已被 Root,核心為訂製版的 Android,而非 Chrome OS

 

至於 Chromecast 的硬體架構,先前 iFixit 也把它拆精光了,得知其使用了來自 Marvell DE3005-A1 的處理器,這雙核心,時脈為 1.2GHz 的晶片同樣為 ARM 的 A9 架構,以他的效能來看,播放影片的效能應是夠的,加上 512MB DDR3 低電壓記體、2GB 儲存空間,以及 Wi-Fi b/g/n 與 Bluetooth 3.0 的無線傳輸功能,的確有空間可做到一些功能,看來可以預期在未來大概可以看到一堆與 Chromecast 有關的奇妙運用了。

LVfRRZmZ3kMUvPUT.large

▲Chromecast 採用來自 Marvell ARM A9 架構的處理器

 

新聞來源: 

Chromecast Teardown

Google Chromecast Root Released, Opening Up All Kinds Of Possibilities [VIDEO]

Tip: You Can Play Local Video Files Through Chromecast

延伸閱讀:

Chromecast 真的是 AirPlay 殺手嗎?

Certification and Testing – Zhaga Consortium.

Certification and Testing

Certification

Zhaga-certified products are listed in the online Certified Products database, and can be identified by the Zhaga logo. Only certified products are allowed to carry the Zhaga logo.

When you see the Zhaga logo on a product, in a product advertisement, or in a product catalogue, you know that this product is Zhaga-certified. Correct usage of the logo can be confirmed by reference to the Certified Products database.

Zhaga-certified products have all been tested by an independent test lab, listed below, which verifies that the product complies with one of the Zhaga specifications (or “Books").

Certification is managed by the Zhaga Logo License Administrator (Zhaga-LLA). The Zhaga-LLA issues product certificates, authorizes test labs, monitors compliance, and acts against inappropriate use of the Zhaga logo.

Authorized Test Labs

The Zhaga-LLA will only certify products that have been tested by an “Authorized Test Lab”.

Zhaga authorizes test labs by location and by specification. Test labs that operate testing facilities at different locations need a separate authorization for each location. Also, Zhaga has created a family of specifications – known as “Books" – and test labs need separate authorization for each Book. 

Authorizing test labs by location and by specification makes it possible for the Zhaga-LLA to verify that the location is capable of testing compliance with a specification.

The Zhaga-LLA has authorized test labs at the following locations:

Book 2:

  • DEKRA Certification B.V., Utrechtseweg 310, 6812 AR  ARNHEM, The Netherlands
  • VDE Testing and Certification Institute, Merianstrasse 28, 63069 Offenbach, Germany
  • UL LLC. 7036 Snowdrift Road, Allentown, PA 18106

Book 3:

  • DEKRA Certification B.V., Utrechtseweg 310, 6812 AR  ARNHEM, The Netherlands
  • VDE Testing and Certification Institute, Merianstrasse 28, 63069 Offenbach, Germany
  • UL LLC. 7036 Snowdrift Road, Allentown, PA 18106

Book 4:

  • DEKRA Certification B.V., Utrechtseweg 310, 6812 AR  ARNHEM, The Netherlands
  • UL LLC. Via XXV Aprile, 3/B, 20875 Burago di Molgora (MB) Italy
  • VDE Testing and Certification Institute, Merianstrasse 28, 63069 Offenbach, Germany

Book 5:

No test lab authorized yet.

Book 6:

No test lab authorized yet.

Book 7:

  • DEKRA Certification B.V., Utrechtseweg 310, 6812 AR  ARNHEM, The Netherlands
  • UL LLC. Via XXV Aprile, 3/B, 20875 Burago di Molgora (MB) Italy
  • VDE Testing and Certification Institute, Merianstrasse 28, 63069 Offenbach, Germany

Book 8:

  • DEKRA Certification B.V., Utrechtseweg 310, 6812 AR  ARNHEM, The Netherlands
  • UL LLC. 7036 Snowdrift Road, Allentown, PA 18106
  • VDE Testing and Certification Institute, Merianstrasse 28, 63069 Offenbach, Germany

Testing Center Agreements

Authorized Test Labs are governed by the rules in the Zhaga Testing Center Agreement between the Zhaga-LLA and companies that operate one or more test labs. A reference copy of this agreement is available as a public download: 20111213 Interim Zhaga Test Center Agreement – reference copy.pdf

The Zhaga-LLA will sign this Testing Center Agreement with any company that meets the following criteria:

  1. the company is a member of Zhaga
  2. the company owns and/or controls one or more testing facilities that are accredited by an accreditor that is a full member of ILAC MRA.

The Zhaga-LLA has concluded Testing Center Agreements with the following companies:

Test labs owned by companies that signed the Zhaga Testing Center Agreement do not automatically become an Authorized Test Lab. Each test lab must be authorized separately, in accordance with the procedure set out in article 3.1 and Annex C of the Zhaga Testing Center Agreement.

What is an LED light engine? – Zhaga Consortium.

What is an LED light engine?

An LED light engine is a combination of one or more LED modules together with the associated electronic control gear (ECG), also known as an LED driver. An LED module contains one or more LEDs, together with further components, but excluding the ECG.

Zhaga treats an LED light engine as a black box, with defined interfaces that do not depend on the type of LED technology used inside the light engine.

The Zhaga specifications define the interfaces between an LED light engine and an LED luminaire. They do not unecessarily restrict the design of the light engine, or the design of the luminaire.

 

Electronic Control Gear included

Zhaga specifications define the interfaces of an LED light engine, which always includes the elctronic control gear (ECG, or LED driver).

For some Zhaga specifications, the control gear is integrated with the LED module, while for others specifications the control gear is in a separate housing.

Zhaga does NOT specify the interfaces between the LED module(s) and the control gear.

無線傳感器網絡標準之爭—ZigBee與Z-Wave比較分析 @ Kenny 四處走走 :: 隨意窩 Xuite日誌.

雜誌 2007 無線RF測試專題

http://wenku.baidu.com/view/406f970c844769eae009edb8.html

​無線傳感器網絡標準之爭—ZigBee與Z-Wave比較分析

  一、ZigBee與Z-Wave發展狀況

  在無線傳感器網絡(WSN)領域中,多數人看好的是ZigBee,畢竟ZigBee有國際標準IEEE 802.15.4為其技術根基,且目標市場較廣、潛在需求用量較大。相對的,丹麥Zensys公司所提出的Z-Wave技術不僅沒有國際標準為其依靠,應用上也僅止於家庭自動化,不似ZigBee能同時適用在工控、醫療、安全等多種領域。
  就技術標準而言Z-Wave已矮於ZigBee一截,而推廣上,Z-Wave也一樣居於弱勢。Zensys極力避免他人認定Z-Wave是該公司專屬自用的技術,一旦如此認定,勢對Z-Wave的普及推廣產生阻力,所以Zensys發起、成立了Z-Wave Alliance的聯盟機構,期望以機構主導此標準的推廣,讓Z-Wave技術獲得更廣泛的採用。
  雖然Z-Wave Alliance已有100多家業者加入成會員,但仔細觀察會員名單,卻相當缺乏IT、通訊、消費性電子等3C領域的重量級業者來支持,相對的國際級的半導體業者幾乎都支持及參與ZigBee,因此Z-Wave連業者陣容、機構氣勢等方面也一樣不如ZigBee。
  不過,Z-Wave的氣勢低落是2006年1月以前的事,在此之後就風雲突變,首先是通訊設備大廠思科(Cisco)宣布投資Zensys公司(Cisco雖投資與支持Z-Wave,但主要也是將Z-Wave技術用在家庭性的無線應用產品上,此方面屬於Cisco旗下Linksys的業務範疇),並加入Z-Wave Alliance機構,之後在同年6月與Intel的創投單位Intel Capital宣布投資Zensys,且一樣加入Z-Wave Alliance,頓時Zensys、Z-Wave獲得IT、通訊兩大領域的重量級業者的力挺,氣勢大增。
  到了2007年1月,軟件巨頭Microsoft也呼應Z-Wave技術,在其.NET Micro Framework(簡稱:.NET MF)上加入對Z-Wave的支持,並宣布與Z-Wave Alliance中的會員業者Leviton 、ControlThink等共同研發Z-Wave應用,再加上PC外圍大廠Logitech(羅技)也推出使用Z-Wave技術的家庭遙控器,從這種種跡象來看,Z-Wave的發展並沒有想像中的悲觀,並且從單純的家庭自動化應用,擴展延伸到數字家庭的領域中。
  此外,Z-Wave標準與Z-Wave功效技術等在近年來也持續進步中,許多技術細節與支持芯片也都有所強化、提升。
  二、Z-Wave技術更新
  過去,若對Z-Wave有所了解的讀者,必然對Z-Wave的傳輸率表現感到印象深刻,不過這並非是強悍的深刻,反而是低落的深刻,Z-Wave的傳輸率僅有9.6kbps ,雖然WSN本就不強調數據的傳輸速度、傳輸量,但也不至於過低,以ZigBee來相對比較,即便不去談論2.4GHz頻段的250kbps傳輸率,在915MHz頻段上也至少有40kbps,或在868MHz頻段上也還有20kbps,ZigBee的三種速率模式都沒有低至9.6kbps。
  也許Z-Wave陣營已了解到此一弱處,並在之後進行強化改進,新的資料顯示,Z-Wave除了原有的9.6kbps速率外,也另增一個可達40kbps速率的模式,以此拉近與ZigBee之間的差距,如此ZigBee除了在2.4GHz的250kbps速率勝過Z-Wave外,另兩種模式與Z-Wave無太大差異。
  而且,Z-Wave提出的新速率能與原有9.6kbps速率的節點裝置完全兼容互通,即是在同一個Z-Wave網絡內能並存運用9.6kbps的節點與40kbps的節點,如此在佈建的規劃設計與延伸上可更便利。
  在使用頻段方面,Z-Wave也與ZigBee差距不大,Z-Wave雖不像ZigBee能在2.4GHz頻段使用,但也能在868MHz及908MHz(具體而言是868.42MHz及908.42MHz)的頻段工作,且與ZigBee相同的,868MHz頻段在歐洲地區運用,908MHz(ZigBee位於相近的915MHz)頻段則是在美國地區運用。
  至於無線發送的調製,Z-Wave依舊是使用原有的GFSK(Gaussian Frequency Shift Keying)方式。相對的,ZigBee在868MHz與915MHz頻段是使用BPSK(Binary Phase-Shift Keying)調製,而在2.5GHz頻段是使用正交式QPSK(Quadrature Phase-Shift Keying)調製。
  三、歐洲與美國地區的差異
  若更進一步了解,可以發現Z-Wave技術與今日其它新推行的無線技術一樣,經常遭遇到各地區電信法規的不同限制,而必須做出各種的因應與妥協。
  舉例而言,Z-Wave在歐洲所使用的868MHz頻段,在法規上有佔空比不得大於百分之一的限制,也就是說:Z-Wave真正在進行無線信號發送的時間與沒有在發送無線信號的時間,比例是1:99,若將時間刻度放大來解釋,即是發送1秒鐘的無線信號後,必須停止、閒置99秒,之後才能進行第二次發送,且發送時間一樣只能持續一秒,接下來又是長達99秒的等待。很明顯的,此項法規的限制也使Z-Wave不易提升其傳輸率。
  當然,在長達99秒的等待過程中,Z-Wave節點(或稱:裝置)可以進入休眠的省電狀態,藉此來降低功耗、節省用電,此方面Z-Wave已能達0.1 %的佔空比,同樣以時間刻度放大的角度來說明,若一樣以100秒為一個週期單位,Z-Wave可以只工作0.1秒,其餘99.9秒的時間都在休眠。
  雖然Z-Wave在歐洲的868MHz頻段上有佔空比的限制,但相對的在美國908MHz頻段上就沒有這項限制,所以理論上Z-Wave日後可以在908MHz頻段上有更高的速率提升空間。
  不過,美國的908MHz頻段卻也有另一項缺點,即是對發送功率進行限制,其發送功率不得高於1毫瓦,相對的歐洲在這方面的規範反而較寬鬆,只要在25mW內都屬合法使用,發送功率限制的結果也會連帶限制Z-Wave的發送距離、無線覆蓋率。至於ZigBee方面目前的最大發送功率也是在1mW(0dBm)內。
  四、二者間技術上的差異
  既然談及發送距離,那麼也必須比較Z-Wave與ZigBee間的發射差異,Z-Wave的發送距離為100英呎(約30公尺),且要達到如此距離必須在電波的傳送路徑上沒有任何阻擋,然而這並不表示Z-Wave無法進行穿透性傳輸,Z-Wave的無線發送依舊可以穿牆收發,不過穿越阻隔物的代價是減損傳輸距離,目前Z-Wave陣營尚未公佈穿透性傳輸表現的相關信息,只以不同的穿透材質而有不同的距離折損來說明。
  同樣的,ZigBee方面也並未有完整具體的傳輸距離信息,僅有32英呎∼246英呎(10公尺∼75公尺)的概略描述,且一樣表示必須依據實際發送的環境而定。
  Z-Wave與ZigBee之間除了傳輸速度、傳輸距離有別之外,在節點數目、拓樸型態、安全加密上也都各有不同。
  首先是節點數目,此方面Z-Wave並未有所改變,依舊是每個網絡內最多232個節點,若想與更多節點聯繫,就必須使用跨網的橋接(Bridge)技術才行。
  至於ZigBee方面,ZigBee的節點尋址達16-bit,理論上可以達65,536個節點,此遠遠勝過Z-Wave,此外ZigBee還能選用更大範疇的64-bit尋址,如此節點數就不可限量。更進一步的,IETF已擬定讓ZigBee與IPv6接軌整合的6loWPAN(全稱為:IPv6 over Low power WPAN),ZigBee節點將可以廣大Internet結合,這些方面Z-Wave都無法比擬。
  另外在連接拓樸方面,Z-Wave只有一種拓樸型態,即是網狀(Mesh),而ZigBee除了也有網狀拓樸外,也支持星狀(Star)、叢集狀(Cluster)等拓樸。值得注意的是,各節點除了自身所需的信號收發外,也會代為中繼傳遞其它節點的信號,無論是自身需求的收發或轉傳其它節點的信號,該節點都會脫離休眠狀態而進入運行狀態,而經常扮演中繼工作的節點將比其它節點更為忙碌,功耗也會較多,所以在實際佈建時的設計規劃上,也會盡量以非使用電池運行的裝置來擔任忙碌型中繼的角色。
  至於安全加密方面,ZigBee使用128-bit的AES對稱加密,而Z-Wave則是尚未有任何加密的設計,這其實不難想像,在Z-Wave最初只有9.6kbps的傳輸帶寬下,若再進行加密性傳輸,則實質數據的傳遞量將會更少,因此不太可能在9.6kbps中再行加密,不過Z-Wave將速率提升至40kbps後,也應該開始考慮提供加密的措施。
  五、二者間在應用領域的差異
  平心而論,Z-Wave在訂立之初就以家庭自動化應用為目標,而ZigBee則是追求更廣泛應用為目標,兩者各在最初指導思想就有不同的考慮,自然在規格上也有諸多落差,此實不能單就規格數據表現來論斷。
  特別是Z-Wave獲得Cisco、Intel、Microsoft等資通訊大廠的支持後,Z-Wave已從單純的家庭自動化應用,開始擴展延伸到數字家庭領域,甚至是家庭自動化與數字家庭的接軌整合等,加上Z-Wave的各項技術仍在持續提升,從9.6kbps增進到40kbps可說是該陣營的一大鼓舞,同時也是給ZigBee更大的競爭壓力。
  此外,ZigBee原先期望也用於PC外圍或消費性電子的遊戲玩具中,但就目前來看,無論是PC所用的無線鼠標、無線鍵盤,還是Nintendo Wii的無線遊戲控制器、Sony PlayStation 3的無線遊戲控制器,都是使用藍牙而非ZigBee,加上藍牙芯片已多年大量量產,組件的量價均攤已達高度成熟,ZigBee當初設定以更低價格取代藍牙在控制領域應用,此一構想的實現難度也日益增高。
  由此來看,現在最需要擔心的反而不是規格表現偏弱的Z-Wave,反而是追求應用領域最大化的ZigBee,很有可能落入“樣樣通、樣樣松”的結果。Z-Wave佔據家庭(家庭自動化、數字家庭;Bluetooth擁有信息(無線鍵盤/鼠標)、通訊(無線耳機/話筒)、消費性電子(電玩控制器),或許最後最適合ZigBee的將會落在工控、醫療等領域。

松翰 Sonix Technology Co., Ltd.

Sonix Technology Co., Ltd.

SN93300

Wireless multimedia processor


[放大圖]

 

Sonix SN93300 series is a 2.4GHz wireless multi-media processor that target on wireless transmission for video, audio and data applications. It supports at least 3 popular types of 2.4GHz RF transceiver, including Nordic® nRF24L01, AMICCOM® A7121, MuChip® MV400. Within bandwidth limit of 2Mbps, 3Mbps and 4Mbps data rate for each brand RF transceiver, SN93300 supports 1-way video, 2-way audio and 2-way data transmission. SN93300 implements most popular LCD panel interfaces and supports ISP CMOS sensor interface. For PC peripheral applications, it supports USB 1.1 interface and follow UVC/UAC driver-less class compliance of Microsoft® XP® SP2 or VISTA® OS.

 

 

  • Support 2.4GHz ISM band FSK RF transceivers.
  • Firmware protocol base adaptive FHSS (frequency hopping spreading spectrum). Meet telecommunication regulations.
  • FCC 15.247
  • CE ETSI EN 300 328-1
  • Built-in baseband supports antenna diversity for receiver.
  • Built-in PLL for internal clock generation with input crystal frequency of 12MHz.
  • Built-in wake up function for remote power-on/off control.
  • Using external serial flash to store customized code and data.
  • No external SDRAM needed.
  • Path delay from Tx camera to Rx display has less than 0.1 second for video and audio.
  • Remote command delay has less than 0.01 second.
  • Packages of LQFP 48/80/100
  • USB 1.1 interface.
  • USB Video Class 1.1 compliant.
  • USB Audio Class 1.0 compliant.
  • Support ISP CMOS sensor interface with 16-bit YUY2 format.
  • 1/2, 1/4 image scaling function to keep fully view angle for small size panel.
  • Support 1.5X or 2X digital zoom-in function for VGA sensor.
  • For VGA sensor, combined scaling and windowing function provides similar view angle for QVGA/QQVGA output format.
  • Built-in JPEG codec.
  • Built-in TV encoder.
  • Support image DSP technology to eliminate blocking effect.
  • Support digital microphone interface to eliminate MIC interference by RF antenna.
  • Support snapshot function and store images in serial flash.
  • Preview snapshot by
  • LCD panel
  • PC software via USB download
  • Receiver image frame rate
  • Max. 30 frame/sec @ QQVGA
  • Max. 30 frame/sec @ QVGA
  • Max. 15 frame/sec @ VGA
  • Support OSD (On Screen Display).
  • Maximum 128 characters.
  • Each character has 16×16 or 8×8 dot matrix option.
  • Each character has 4 colors, 1 background color and transparency option.
  • Support panel types: TFT/CSTN/LTPS
  • Video output interfaces:
  • UPS051
  • RGB Dummy
  • 8080 IF (CPU IF)
  • Parallel RGB (8 bit x 3)
  • YUV422 (Sensor IF)
  • BT601 (output h-sync, v-sync, 8/16 bit data, 13.5MHz clock)
  • BT656 (output 8 bit data, 27MHz clock)
  • CVBS
  • Video input interfaces:
  • YUV422 (Sensor IF)
  • BT656
  • Built-in 4 of 10 bit, 8K/16K sampling rate ADC for microphone, AD key, battery detection and general purpose analog input.
  • Built-in 10 bit, 8K/16K sampling rate DAC for analog audio output.
  • Support GPIO and PWM pin for local or remote control.
  • PWM pins support stepper motor control.
  • Each GPIO has wakeup capability.
  • Support multiple ID for security.
  • System current assumption:
  • Camera-site : 100mA~200mA (RF+PA+SN93300+Sensor)
  • Monitor-site : 100mA~200mA (RF+PA+SN93300+Panel)

聯陽半導體 ITE Tech. Inc.

ITE Tech. Inc.

IT9500: ccHDtv Transmitter

 

IT9500 is a series of highly integrated transmitter for ccHDtv camera, and other personal, community, or professional digital TV head-end applications. The core of IT9500 is a DVB-T COFDM modulator. The high level of integration of IT9500 significantly decreases the power consumption, board size and cost of modulators in digital TV transmitter. With IT9500, a low cost, low power, compact, reliable, high bandwidth and wireless (or wired) full HD delivery solution is easily achieved.

IT9500 offers very low total bill of materials (BOM) solutions. It includes processing units for forward error correction coding and digital modulation, D/A IQ converter, low-pass filters, and local oscillator for the external mixer. IT9500 series also supports flexible input interfaces, including embedded USB 2.0 interface, and serial/parallel TS interface input/output with built-in de-multiplexer.

IT9500 series is compliant to the non-hierarchical transmission specified in DVB-T (ETSI EN 300 744). A (204,188) Reed-Solomon encoder capable of correcting 8 error bytes is used to generate parity bytes for each input TS packet. The code rates of the punctured convolution encoder include 1/2, 2/3, 3/4, 5/6, and 7/8. Only native interleaving is used in IT9500. The output signal bandwidth is configurable from 2 MHz to 8 MHz. The supported signal constellations include QPSK, 16-QAM, and 64-QAM. FFT modes of 2k and 8k and guard intervals of 1/4, 1/8, 1/16, and 1/32 specified in EN 300 744 are supported. The transmission parameters are register-programmable, and are embedded in the Transmission Parameter Signaling (TPS) information as required by EN 300 744.

A complete set of application programming interface (API) is available, facilitating fast and easy integration into products on Windows Mobile, Windows CE, Windows 8, Windows 7, Windows XP, Vista, Linux, and many other operating systems.Furthermore, a complete set of USB drivers for Windows 8/7/XP/Vista, Windows Mobile/CE, and Linux are providedfor IT9500.

http://www.ite.com.tw/TW/products_kind.aspx?CategoryID=2

nModulator

nETSI, DVB-T/H (EN 300 744 V1.5.1) Compliant baseband transmitter for Digital Terrestrial Television

nConfigurable code rate: 1/2,2/3,3/4,5/6,7/8

nProgrammable QPSK, 16-QAM and 64-QAM Symbol Mapping

nConfigurable support for 2k and 8k FFT

nProgrammable Guard Interval (1/4, 1/8, 1/16, 1/32)

nSupports variable channel band width from 2 MHz to 8 MHz

nZero I/F complex base band I/Q output with integrated DAC and anti-aliasing filter

nMER > 40dB

nCarrier Suppression > 50dB

nSpectrum Shoulders: 55 dB for perfect adjacent-channel operations