Utilize este identificador para referenciar este registo:
https://hdl.handle.net/1822/4833
Título: | A CMOS mixed-signal interface with a RF transmitter for a micromachined soil moisture sensor |
Autor(es): | Morais, Raul Valente, A. Couto, Carlos Correia, J. H. |
Palavras-chave: | Wireless Sigma - Delta Soil-Moisture sensors RF Transmitter |
Data: | 22-Jun-2003 |
Editora: | IEEE |
Citação: | IEEE INTERNATIONAL SYMPOSIUM ON INDUSTRIAL ELECTRONICS, Rio de Janeiro, Brazil, 2003 – “IEEE International Symposium on Industrial Electronics : ISIE’03 : [proceedings]”. New Piscataway : IEEE, 2003. vol. 2. ISBN 0-7803-7912-8. p. 1-4. |
Resumo(s): | This paper describes a CMOS mixed-signal interface with a RF transmitter. This die is assembled in a Multi-Chip-Module (MCM) micro-system together with the micromachined soil moisture sensor to achieve a cost effective solution with accurate and reliable measurements for soil moisture in agriculture. The soil moisture probe, based on Dual-Probe Heat-Pulse (DPHP) method, is fabricated in bulkmicromachining technology. The DPHP method is based on the measurement of the maximum temperature rise at some distance from the heater, after applying a heat-pulse. The measurement of the temperature rise is obtained by subtracting soil temperature from the probe temperature. The mixed-signal interface is based on a pre-amplification stage and first-order sigma-delta modulator. The bit-stream output of the modulator is then applied to a counter as a first order decimation filter thus providing a 12-bit readout sample. Prior to transmission, data is encoded as a pulse width modulated (PWM) signal and then transmitted by means of an amplitude shift-keying (ASK) modulation. The transmitter features a VCO phase locked to the quartz crystal reference of 13.56 MHz to achieve a carrier frequency of 433.92 MHz. A RF power amplifier based on class E topology was chosen. The CMOS mixed-signal interface with a RF transmitter has been implemented in a single-chip using a standard CMOS process (AMI 0.7 µm, n-well, 2 metals and 1poly). |
Tipo: | Artigo em ata de conferência |
URI: | https://hdl.handle.net/1822/4833 |
ISBN: | 0-7803-7912-8 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | DEI - Artigos em atas de congressos internacionais |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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ISIE03.pdf | Documento principal | 643,39 kB | Adobe PDF | Ver/Abrir |