Modulation and filtering device

• US 4,003,002 A
• Filed: 08/27/1975
• Issued: 01/11/1977
• Est. Priority Date: 09/12/1974
• Status: Expired due to Term

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Snijders, Wilfred Andre Maria, VAN Gerwen, Petrus Josephus, Verhoeckx, Nicolaas Alphonsus Maria, VAN Essen, Hendrik Arie
• Primary Examiner(s): Kominski, John
• Application Number:
  US05/608,392
• Time in Patent Office: 503 Days
• Field of Search: 325/30, 325/163, 176/66 R, 332/9, 332/9 T, 332/10
• US Class Current: 332/185
• CPC Class Codes: H03C 1/00 Amplitude modulation H03C5/00, H03C7/00 take precedence
• CPC Class Codes: H03H 17/06 Non-recursive filters
• CPC Class Codes: H04L 27/04 Modulator circuits; Transmitter circuits

Abstract

A digital data transmitter is described, whose line carrier frequency need not be an integral multiple of one half the clock frequency of the digital input signal. Use is made of a digital filter for increasing the sampling frequency to a value which is twice the modulator carrier wave frequency.

Claims

1. Modulation- and filtering device for digital signals comprising means for filtering the digital signals and means for modulating the filtered digital signals, on a modulator carrier wave characterized in that signal samples of the digital input signal, which occur at a first sampling frequency are converted in a digital filter to signal samples of a second sampling frequency, which is twice as high as the modulator carrier wave frequency and the signal samples at the second sampling frequency are modulated in the modulator with signal samples of the modulator carrier wave which occur at the same second sampling frequency the digital filter being adapted to have a band-pass filter characteristic.