Subscriber unit for wireless digital telephone system

• US 4,994,802 A
• Filed: 10/12/1988
• Issued: 02/19/1991
• Est. Priority Date: 08/07/1986
• Status: Expired due to Term

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: International Mobile Machines Corporation (InterDigital, Inc.)
• Inventors: Johnson, Karle J., Smetana, Bruce A., Paneth, Eric, Avis, Graham M., Yehushua, Moshe, Westling, Gregory L., Earlam, Sandra J. K., Critchlow, David N.
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Young, Brian K.
• Application Number:
  US07/256,579
• Time in Patent Office: 860 Days
• Field of Search: 341/122, 341/123, 341/124, 341/125, 341/155, 341/156, 328/117, 242/465, 364/734
• US Class Current: 341/122
• CPC Class Codes: H03D 2200/005 Analog to digital conversion
• CPC Class Codes: H03D 2200/0052 Digital to analog conversion
• CPC Class Codes: H03D 2200/0058 using a digital filter with interpolation
• CPC Class Codes: H03D 2200/0062 Computation of input samples, e.g. successive samples
• CPC Class Codes: H03D 2200/0082 Quadrature arrangements
• CPC Class Codes: H03D 3/006 by sampling the oscillations and further processing the samples, e.g. by computing techniques H03D3/007 takes precedence
• CPC Class Codes: H03D 3/007 by converting the oscillations into two quadrature related signals H03D3/245 takes precedence
• CPC Class Codes: H03D 7/161 all the frequency changers being connected in cascade
• CPC Class Codes: H03D 7/165 at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002
• CPC Class Codes: H03H 17/0657 where the output-delivery frequency is higher than the input sampling frequency, i.e. interpolation
• CPC Class Codes: H03L 7/095 using a lock detector H03L7/087 takes precedence
• CPC Class Codes: H04B 1/50 using different frequencies for the two directions of communication
• CPC Class Codes: H04L 27/1525 using quadrature demodulation
• CPC Class Codes: H04L 27/2338 using sampling H04L27/2331 - H04L27/2335 take precedence
• CPC Class Codes: H04M 1/72502 with one base station connected to a single line

Abstract

An analog to digital converter system utilizable in a wireless digital telephone network, the system comprising a circuit to produce an analog signal, and a circuit for amplifying this signal, mixing the amplified signal with a signal from a timing circuit and applying the output of the mixer to a sample and hold circuit; the output of the sample and hold circuit being then applied to an analog to digital converter, the output of which is applied to a FIFO, whose output is then available for further processing.

Claims

1. An analog to digital converter system comprising:

means to produce an analog signal;

amplifier means for receiving said analog signal and amplifying the same;

a mixer for receiving the amplified analog signal from said amplifier means and combining it with a timing signal received from a timing means;

a sample and hold circuit for receiving the combined signal from said mixer and applying its output to an analog to digital converter to form a digital signal; and

a FIFO for receiving said digital signal and providing its output for further processing.