PROM compensated, digitally controlled vector modulators

Citation metadata

Date: Aug. 1995
From: Microwave Journal(Vol. 38, Issue 8)
Publisher: Horizon House Publications, Inc.
Document Type: Article
Length: 778 words

Document controls

Main content

Article Preview :

The RPU 8500 series vector modulators provide an accurate phase shift at constant amplitude over a broad radio frequency (RF) band using programmable read-only memory (PROM) compensation. This unique merger of RF and digital technology provides a product with good electrical performance at a competitive cost. Figure 1 shows a functional block diagram of the product, including the digital control portion of the circuit and the circuit's RF portion.

The digital control portion of the circuit begins with an eight-bit digital input word, which represents the amount of phase shift that is required. The eight-bit word provides a phase shift resolution of 1.4 [degrees]. The digital input signal is fed through a line receiver in order to provide an accurate and stable signal.

Information in the eight-bit phase control drives two 12-bit PROMs. These PROMs contain the 12-bit control signals that drive the I and Q channels of the vector modulator for each of the 512 possible digital input words.

One of the key elements of the vector modulator is the PROM circuit design. The PROMs contain sufficient memory capacity to allow for the incorporation of nine different compensation values. Through the use of...

Source Citation

Source Citation   

Gale Document Number: GALE|A17405957