R&S ZVA
Repairs
1177.5333.02
3.7
E-11
The signal reflected or transmitted by the DUT is fed to the port, coupled out in one of the two couplers
of the two used converters and fed to the receiver section where it is converted to an IF below 500 MHz
by harmonic mixing.
The internal reference frequencies are generated on the frequency reference board. The 128-MHz
reference frequency is generated there as an internal device reference.
The following sections describe the various boards in greater detail.
Reflectometer ZVA8
A reflectometer board comprising a
bridge unit
, a
generator section (Generator)
and a
receiver
section (Receiver)
is incorporated in every port (Port1 to 4). These three components are screwed
together to form a compact unit.
Bridge unit
The bridge unit is a resistive coupler which is used to separate the signal going to the DUT from the
signal coming from the DUT. The reference signal (= measure of the signal to the DUT) is also obtained
from the bridge unit. The reference signal provides a reference for relative measurements.
Generator
The generator contains three broadband amplifier stages which boost the signal coming from the
synthesizer to a level > 20 dBm. Limiter diodes protect the output stage from ESDs. A total of three
adjustable attenuators form the setting element to keep the output level constant and to attenuate it
electronically.
Receiver
The receiver section has two channels (measurement channel and reference channel) and uses single
conversion. Every channel contains a buffer amplifier, for each of the frequency ranges 300 kHz to
4 GHz and 4 GHz to 8 GHz, a mixer with LO amplifiers and an IF amplifier. In the mixer, the input signal
is directly converted to the IF range, approx 15 to 21 MHz. The inputs are protected by limiter diodes.
Reflectometer Unit ZVA24
A reflectometer unit comprising a
coupler unit
, a
generator section (Generator)
and a
receiver
section (Receiver)
is incorporated in every port (Port1 to 4). The Generator and the Receiver are
screwed together to form a compact unit.
Coupler unit
The coupler unit contains a bias-T and two directional couplers. One coupler is used to separate the
signal going to the DUT from the signal coming from the DUT. The reference signal (= measure of the
signal to the DUT) is obtained from the second coupler. The reference signal provides a reference for
relative measurements.
Generator
The generator contains a frequency doubler for the range 8 GHz to 16 GHz, a switchable filter unit, a
second frequency doubler with filter for the range 16 GHz to 24 GHz and a broadband amplifier for the
frequency range 10 MHz to 24 GHz with two adjustable attenuators to keep the output level constant
and to attenuate it electronically.
Summary of Contents for ZVA8
Page 437: ...Documents R S ZVA 1177 5333 02 5 2 E 11 Spare Parts List Mechanical Drawings...
Page 472: ......
Page 473: ......
Page 474: ......
Page 475: ......
Page 476: ......
Page 477: ......
Page 478: ......
Page 479: ......
Page 480: ......
Page 481: ......
Page 482: ......
Page 483: ......
Page 485: ......
Page 487: ......
Page 488: ......
Page 489: ......
Page 490: ......
Page 491: ......
Page 492: ......
Page 493: ......
Page 494: ......
Page 495: ......
Page 496: ......
Page 497: ......
Page 498: ......
Page 499: ......
Page 500: ......
Page 501: ......
Page 502: ......
Page 503: ......
Page 504: ......
Page 505: ......
Page 506: ......
Page 507: ......
Page 508: ......
Page 509: ......
Page 510: ......
Page 511: ......
Page 512: ......
Page 513: ......
Page 514: ......
Page 515: ......
Page 516: ......
Page 517: ......
Page 518: ......
Page 519: ......
Page 520: ......
Page 521: ......
Page 522: ......
Page 523: ......
Page 524: ......
Page 525: ......
Page 526: ......
Page 527: ......
Page 528: ......
Page 529: ......
Page 530: ......
Page 531: ......
Page 532: ......
Page 533: ......
Page 534: ......
Page 535: ......
Page 536: ......
Page 537: ......
Page 538: ......
Page 539: ......
Page 540: ......
Page 541: ......
Page 542: ......
Page 543: ......
Page 544: ......
Page 545: ......
Page 546: ...1145 1078 02 5 38 E 10 Circuit Diagram...
Page 547: ......
Page 548: ......
Page 549: ......
Page 550: ......
Page 551: ......
Page 552: ......
Page 553: ......
Page 554: ......
Page 555: ......
Page 556: ......
Page 557: ......
Page 558: ......
Page 559: ......
Page 560: ......
Page 561: ......
Page 562: ......
Page 563: ......
Page 564: ......
Page 565: ......
Page 566: ......
Page 567: ......
Page 568: ......
Page 569: ......
Page 570: ......
Page 571: ......
Page 572: ......
Page 573: ......
Page 574: ......
Page 575: ......
Page 576: ...1177 5333 02 5 37 E 11 Circuit Diagrams...
Page 577: ......
Page 578: ......
Page 579: ......
Page 580: ......
Page 581: ......
Page 582: ......
Page 583: ......
Page 584: ......
Page 585: ......
Page 586: ......
Page 587: ......
Page 588: ......
Page 589: ......
Page 590: ......
Page 591: ......
Page 592: ......
Page 593: ......
Page 594: ......
Page 595: ......
Page 596: ......
Page 597: ......
Page 598: ......
Page 599: ......
Page 600: ......
Page 601: ......
Page 602: ......
Page 603: ......
Page 604: ......
Page 605: ......
Page 606: ......