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14 records (took 0.02 seconds)

    1.
    发明专利
    未知

    公开(公告)号：AT106640T

    公开(公告)日：1994-06-15

    申请号：AT89902567

    申请日：1989-01-17

    Applicant: MOTOROLA INC

    Inventor： GAILUS PAUL HOWE ,  TURNEY WILLIAM JOSEPH ,  YESTER FRANCIS RICHARD

    IPC: H03M3/00 ,  H03M3/02 ,  H03M3/04 ,  H04B1/10 ,  H04B14/06

    Abstract: An improved apparatus and method for a sigma delta converter for bandpass signals is disclosed, suitable for use in mobile radio applications, between the front end and digital signal processing stages, that includes at least one bandpass filter, an n-level quantizer, an n-level digital-to-analog (D/A) converter, and a direct current (DC) feedback network. The sigma delta converter for bandpass signals may be configured in a second order or a fourth order embodiment and achieves analog-to-digital conversion of a signal having a non-zero frequency carrier or suppressed carrier with improved signal-to-noise ratio performance and with minimal quantization error. As a result, the sigma delta conversion occures earlier in a receiver chain and a dynamic range of about 95-98 dB is achieved.

    3.
    发明专利
    未知

    公开(公告)号：AT111288T

    公开(公告)日：1994-09-15

    申请号：AT88906319

    申请日：1988-06-06

    Applicant: MOTOROLA INC

    Inventor： YESTER FRANCIS RICHARD ,  TURNEY WILLIAM JOSEPH ,  GAILUS PAUL HOWE

    IPC: H03J5/02 ,  H04B1/16 ,  H04Q7/00

    Abstract: A low power digital receiver (10) is provided that contemporaneously selects the lowest possible sampling signal frequency (34) (from a plurality of available sampling signals), and received signal level (28) to properly digitize (32) and recover a desired signal. Digitization is performed after the first IF using broadband stages (28, 30, and 32) that are temporarily enabled (44) to rapidly digitize the first IF signal. This, together with the low sampling rate, minimizes the power consumption of the receiver (10) thereby permitting portable and mobile digital receiver embodiments.

    Radio frequency filter having temperature compensated dielectric resonator
    9.
    发明专利
    Radio frequency filter having temperature compensated dielectric resonator 未知

    公开(公告)号：GB2183928A

    公开(公告)日：1987-06-10

    申请号：GB8530190

    申请日：1985-12-06

    Applicant: MOTOROLA INC

    Inventor： GANNON MARK ALAN ,  YESTER FRANCIS RICHARD ,  KOMMRUSCH RICHARD STEPHEN

    IPC: H01P1/213 ,  H01P7/10

    Abstract: An RF filter (100) includes a ceramic resonator (116) sandwiched between first and second dielectric compensating discs (114 and 120) for temperature compensation, low loss mounting and heat sinking of the ceramic resonator (116). The dielectric material of the compensating discs has a frequency/temperature coefficient of opposite polarity to, and a thermal conductivity greater than, that of the resonator. Good thermal contact between the ceramic resonator (116) and discs (114 and 120) is produced by a compressive force applied by the enclosing housing (112, 124, 128). The resonant frequency of the RF filter may be tuned by means of a tuning shaft (102) and ceramic tuning slug (118) which is insertable into a hole in the resonator (116). Input and output signals are coupled to the RF filter via respective probes (122).

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