← Back to Patent Explorer
US3868568A Expired / Lapsed US ⏱️ 0.0 years remaining

Spectrum analyzer

Assignee: Advantest Corp
•
Filing: 1973-06-18
•
Granted: 1975-02-25
•
Expires: 1993-06-18
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A spectrum analyzer of the heterodyne type including a local oscillator having voltage controlled frequency, first mixer means coupled to receive a spectrum of input frequencies and to mix them with said frequency from the local oscillator and produce intermediate frequencies, narrow band filter means coupled to receive said intermediate frequencies and to select substantially one frequency thereof, second mixer means connected to mix said local oscillator frequency and the output of said filter means and deliver an output frequency corresponding with a selected input frequncy, counter means, timed interval gate means operative when actuated to admit cycles of said output frequency of the second mixer means into said counter means, waveform generator means operative to generate series of waveforms including interspersed ramp waveforms and square waveforms, oscillograph means having a first-axis input connected to receive for display components of intermediate frequencies selected by the filter means and having a second-axis input connected to receive said waveforms to sweep the oscillograph means, and said square waveform being coupled to actuate said gate means to admit said selected frequency into the counter means to have its cycles counted for the duration of said interval.

Inventors

  • 👤 Hitoshi Ashida
  • 👤 Kenichiro Yasaka
  • 👤 Motosuke Tanabe
  • 👤 Yuuji Yoshino

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 10:04
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/16; G01R23/165

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 190 words
A spectrum analyzer comprising, a local oscillator having voltage controlled frequency, first mixer means coupled to receive a spectrum of input frequencies and to mix them with said frequency from the local oscillator and produce intermediate frequencies, narrow band filter means coupled to receive said intermediate frequencies and to select substantially one frequency thereof, second mixer means connected to mix said local oscillator frequency and the output of said filter means and deliver an output frequency corresponding with a selected input frequency, counter means, timed-interval gate means operative when actuated to admit cycles of said output frequency of the second mixer means into said counter means, waveform generator means operative to generate series of waveforms including interspersed ramp waveforms and square wave forms, the output of said series of waveforms controlling said voltage controlled oscillator to sweep or fix the frequency thereof, oscillograph means having a first axis input connected to receive for display components of intermediate frequencies selected by the filter means and having a second axis input connected to receive said waveforms to sweep the oscillograph means, and said square waveform being coupled to actuate said gate means.
Claim 2
Dependent Claim 190 words
A spectrum analyzer comprising, a local oscillator having voltage controlled frequency, first mixer means coupled to receive a spectrum of input frequencies and to mix them with said frequency from the local oscillator and produce intermediate frequencies, narrow band filter means coupled to receive said intermediate frequencies and to select substantially one frequency thereof, second mixer means connected to mix said local oscillator frequency and the output of said filter means and deliver an output frequency corresponding with a selected input frequency, counter means, timed-interval gate means operative when actuated to admit cycles of said output frequency of the second mixer means into said counter means, waveform generator means operative to generate series of waveforms including interspersed ramp waveforms and square wave forms, the output of said series of waveforms controlling said voltage controlled oscillator to sweep or fix the frequency thereof, oscillograph means having a first axis input connected to receive for display components of intermediate frequencies selected by the filter means and having a second axis input connected to receive said waveforms to sweep the oscillograph means, and said square waveform being coupled to actuate said gate means.
Claim 3
Dependent Claim 103 words
A spectrum analyzer as set forth in claim 1, including means for extending the frequency range of the analyzer comprising, a second local oscillator, a third mixer means coupled to the second oscillator and interposed at the output of the filter means to receive the selected intermediate frequency and operative to transpose it in one direction by a factor determined by the second oscillator frequency, and a fourth mixer means coupled to said second oscillator and interposed at the output of the second mixer means to receive its output frequency and operative to transpose it by the same factor in the opposite direction.
Claim 4
Dependent Claim 31 words
A spectrum analyzer as set forth in claim 1, wherein said waveform generator is operative to generate a series of waveforms in which said ramp waveform and said square waveforms alternate.
Claim 5
Dependent Claim 32 words
A spectrum analyzer as set forth in claim 1, wherein said waveform generator is operative to generate said ramp waveform with a square waveform interposed within a cycle of the ramp waveform.

References Cited (Backward Citations)

US3045233A Cited
US3110861A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-02-24 1978-08-26 1979-02-25 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-02-24 1982-08-26 1983-02-25 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-02-24 1986-08-26 1987-02-25 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag