Pentrix, formed in 1962, was a company that made spectrum analyzer plug-ins for Tektronix oscilloscopes.
Tek-Talk September 1964 said:
TEK NEWSREEL: Acquisition of Pentrix Corporation, Brooklyn manufacturer of spectrum analyzers, was announced in April. The small company became part of Tektronix through transfer of 30,002 shares of Tektronix, Inc. stock. In June 8330 shares were issued. The remaining 21,672 shares will be issued in installments over the next four years, contingent on spectrum analyzer sales. Three Pentrix owners – Arnold Frisch, Larry Weiss and Morris Engelson – joined Tektronix Engineering in June to continue their work on spectrum analyzers.
Pentrix product was designed as a plugin unit for several Tektronix oscilloscopes, converting them to frequency-based instruments. According to market researchers, the spectrum analyzer market is in the neighborhood of $8 – 10 million per year. “Pentrix fits well into Tektronix’ manufacturing and marketing organization and offers new markets for both its present and acquired products,” Bob Fitzgerald (vice-president, Operations) stated when making the announcement.